The goal was to evaluate the hysteresis performance of segmented buckling resistant braces with low yield point steel LYP160, the monotonic tensile and cyclic loading tests of LYP160 were conducted and the corresponding laws have been obtained. According to the load-displacement curves of the specimen, the low yield point steel was characterized by good ductility and energy absorption ability. With the consideration of Chaboche model on the materials, the cyclic loading was simulated by ABAQUS and the cyclic hardening parameters of low yield point steel were obtained. On this basis, the hysteretic properties of buckling resistant braces under cyclic loads were simulated and analyzed. After the analysis and comparison of buckling resistant braces specimens with isotropic core plate and segmented variable section core plate, it can be found that: When the buckling resistant braces with isotropic core plate was loaded to L/100, the lateral deformation of BRB would reach 17mm and the seriously squeezed would observe on lateral constraint members. The buckling resistant braces would fail due to the accumulation of deformation on lateral constraint members at both ends of BRB. When the segmented buckling resistant braces was applied, the core plate with variable section would yield first in the middle part, other parts could still continue to consume energy due to the action of the limit plate. It would avoid the phenomenon that other parts could not continue to consume energy after the core plate failed at one point first. Under the action of cyclic loads, the stiffness of the segmented buckling resistant brace was constant and the better ability to consume energy was reflected.

The purpose of this study is to investigate the annual degradation rates of photovoltaic (PV) systems composed of PV modules based on recent crystalline silicon (c-Si) PV technologies. We investigated the annual degradation rates of four PV systems composed of different c-Si PV technologies, comprising p-type multi-crystalline silicon with a passivated emitter rear cell, n-type silicon heterojunction, p-type single-crystalline silicon with an aluminum back surface field, and n-type single-crystalline silicon solar cell technologies. These systems were located in Gunma Prefecture in Japan and were measured over six years. Furthermore, the effects of soiling on the annual degradation rates of these PV systems were examined by partially surface cleaning the PV arrays two times. The results obtained indicate that the apparent annual degradation rates of the PV strings before surface cleaning were 0.8, 1.6, 1.4, and 1.2%/year, respectively, because of optical losses due to dust particles. However, the inherent annual degradation rates of the PV strings after surface cleaning were 0.1, 0.6, 0.0, and 0.3%/year, respectively. These low degradation rates indicate that the PV systems composed of the recent c-Si PV technologies all offered reasonably stable performance that was reduced by 3.6, 5.5, 7.3, and 4.8%, respectively because of the effects of surface soiling, although the surfaces of the PV arrays had been washed by plentiful rainfall under their humid subtropical climatic operating conditions.

The Weizhou X low-permeability reservoir is an offshore reservoir, with a permeability ranging from 0.58×10 -3μm 2 to 470.05×10 -3μm 2, showing strong heterogeneity. In the subsequent water injection development, good results were not always obtained. The main problem was that during the water injection process, the injection pressure increased significantly, resulting in low water injection volume and low water injection efficiency, which could not maintain long-term effective effects on production. Improvement, it is difficult to replenish energy in the formation. Through the analysis of pore-throat structure, water quality compatibility and sensitivity, it is clear that pore-throat blockage is the main reason for low water injection efficiency. Aiming at the present situation that the scaling matter is mainly calcium carbonate, a solution to soil acidification and plugging removal was proposed, and the water injection damage of the actual reservoir was simulated. The indoor acidification experiment was carried out, which showed that the effect of acidification on the transformation of the reservoir was good, and the average rate of transformation is 129.21%. Suggestions are put forward for the effective development of Weizhou X low-permeability reservoirs, the economic benefits of development are improved, and guidance is given for the enhanced injection measures of low-permeability oilfields.

A probabilistic limit equilibrium framework combining empirical load transfer factor and anisotropy of soil cohesion is developed to conduct pile-reinforced slope reliability analysis. The anisotropy of soil cohesion is determined conditioned on that the thrust force direction is parallel to the major principal direction and it is easily combined with load transfer factor, which are related with soil parameters, and pile parameters. The proposed method is illustrated against a homogeneous soil slope. The sensitivity studies of pile parameters on FS (calculated at respective means of soil parameters) and β demonstrated that the anisotropy of soil cohesion tends to pose significant effect on reliability index β than on FS. The effect of anisotropy of soil cohesion on FS is found to be slightly different under different pile locations, whereas its effect on β is observed to be least if piles are drilled at the middle part of slope and more significant effect is observed when piles are drilled at the lower and upper part of slope. The plots from the sensitivity studies provide an alternative tool for pile designs aiming at the target reliability index β. The proposed method contributes to the pile-reinforced slope stability within limit equilibrium framework.

The lossless video coding framework based on HEVC is consisted of prediction and entropy coding, which directly determine the lossless coding efficiency. The initial residuals with large absolute values are directly coded by the lossy coefficient coding techniques in HEVC, which may compromise the lossless coding efficiency. In this paper, an optimized scheme based on transformation and quantization techniques for the HEVC Intra lossless coding is proposed as an additional mode. In the proposed scheme, an initial residual block is divided into two parts: the coefficient block and the second residual block. The coefficient block is derived by the lossy transformation and quantization technics in HEVC. The second residual block is made up with residuals of small absolute values. Both the coefficient block and the second residual block can be efficiently coded by the existing coefficient coding scheme in HEVC. Rate-distortion optimization is employed to choose between the proposed scheme and the transform bypass scheme to achieve the best coding performance for each block. The proposed scheme is implemented into the HM 12.1 software. Experimental results show that the proposed scheme achieves 3.36 percent bit-rate saving on average and up to 12.29 percent compared with the HEVC lossless coding under the Intra main configuration.

In recent years, penetration testing (pen-testing) has emerged as a crucial process for evaluating the security level of network infrastructures by simulating real-world cyber-attacks. Automating pen-testing through reinforcement learning (RL) facilitates more frequent assessments, minimizes human effort, and enhances scalability. However, real-world pen-testing tasks often involve incomplete knowledge of the target network system. Effectively managing the intrinsic uncertainties via partially observable Markov decision processes (POMDPs) constitutes a persistent challenge within the realm of pen-testing. Furthermore, RL agents are compelled to formulate intricate strategies to contend with the challenges posed by partially observable environments, thereby engendering augmented computational and temporal expenditures. To address these issues, this study introduces EPPTA (Efficient POMDP-Driven Penetration Testing Agent), an agent built on an asynchronous RL framework, designed for conducting pen-testing tasks within partially observable environments. We incorporate an implicit belief module in EPPTA, grounded on the belief update formula of the traditional POMDP model, which represents the agent’s probabilistic estimation of the current environment state. Furthermore, by integrating the algorithm with the high-performance RL framework, Sample Factory, EPPTA significantly reduces convergence time compared to existing pen-testing methods, resulting in an approximately 20-fold acceleration. Empirical results across various pen-testing scenarios validate EPPTA’s superior task reward performance and enhanced scalability, providing substantial support for efficient and advanced evaluation of network infrastructure security.

The increasing number of private cars, public transportation vehicles, and pedestrians, as well as the absence of adequate space for these ground amenities, are the primary causes of traffic congestion and accidents in the Kathmandu Valley. Investigations have indicated that the Kathmandu Valley has the greatest traffic accidents despite the heavy presence of government and its agencies there. Most teens and young adults suffer injuries while using motor vehicles. The study’s primary objective is to foresee and prevent such complications by planning for sufficient subsurface infrastructure for the Kathmandu valley’s transportation network. Overlying pressure, lateral earth pressure, live load, uplift pressure, and live surcharge are some of the forces acting on the tunnel, creating unique stress and moment zones. The tunnel meets the following geometric requirements: a) each of the tunnel’s two cells has a clear span of 10 meters and a clear height of 5.5 meters. The side walls, inner walls, top slab, and bottom slab are all 700 mm thick. Soil has built up to a height of 4m over the tunnel’s roof. Construction sequencing, the application of various loads during construction, and expected service life are all taken into account during the design process. Analytical and computer software (SAP 2000) are both used in the tunnel segment’s analysis. Furthermore, the designed tunnel has been evaluated for stability, considering the deflection and shear resistance. The analysis indicates that the tunnel meets the stability requirements, as the checks performed for deflection produce satisfactory results. This implies that the structure is capable of withstanding the applied forces without excessive deflection.

This paper proposes a hierarchical distributed voltage control (HDVC) scheme for active distribution networks (ADNs) with high penetration of photovoltaics based on distributed model predictive control (DMPC) and alternating direction method of multipliers (ADMM). The reactive power outputs of several photovoltaic clusters (PVCs) and photovoltaic (PV) units within each PVC are optimally coordinated to keep PV terminal voltages and the voltages of all critical buses of ADNs within the feasible range and mitigate voltage fluctuations. In the ADN layer, a distributed reactive power control scheme based on DMPC is designed for the PVC, which regulates the voltages of all critical buses to be closed to the rated value and mitigates the reactive power variations. In the PVC layer, the reactive power outputs of PV units are optimized based on ADMM to minimize the voltage deviation of each PV terminal and track the reactive power reference from the PVC control. The proposed HDVC scheme requires communication only between neighboring PVC controller, while each PV controller only communicates with the corresponding PVC controller. This regulates the voltages in a completely decentralized manner and effectively reduces the computation burden of the PVC and PV controllers. A modified Finnish distribution network with 10 PVCs was used to validate the control performance of the proposed HDVC scheme.

At present, the main way to deal with the gas well effusion is to use the over-effusion prediction model to calculate the critical fluid carrying velocity and other factors, which provides data support and theoretical basis for the drainage process, so as to achieve the effect of bringing the effusion out of the wellbore. When the prediction results of the hydrops prediction model are biased, hydrops will be generated at the bottom of the wellbore, resulting in a decrease in gas well productivity. Aiming at the problem that the drag coefficient of the wellbore droplet movement model changes greatly in the process of natural gas production, which leads to the error of the wellbore effusion prediction, the commonly used droplet models and the common drag coefficient models are analyzed and evaluated. Considering that the fitting method of the commonly used drag model has different applicability for each Reynolds number region, the literature review, calculation and verification methods are used. The area with the highest fitting accuracy of each method is divided and sorted, and the model is selected. Compared with the model obtained by the partition and the existing drag model and the experimental value, it is found that the model can effectively reduce the average error rate between the calculated results and the experimental value, and can be better applied to the turbulent area and the highly turbulent area, and is more consistent with the actual working condition.

Off-grid solar systems provide clean and affordable energy.Adoption of off-grid solar energy is becoming increasingly popular in Kenya as a source of renewable energy,with an estimated 6 million people now using off-grid solar power systems.However, the rising off-grid solar systems technology uptake comes with a growing amount of solar e-waste, which can have harmful environmental and health effects if not managed properly.Current data on the exact amount of solar e-waste being generated in Kenya is unavailable and this amount will continue to rise with the expiry of many of these off-grid solar systems lifespans.This study through stakeholder's workshop engagement and document analysis approaches,established that the country has robust general waste policy,legal and institutional framework but there is no specific policies and regulations on off grid-solar electronic waste management,just like it is the case in many developing countries. In addition, there is a lack of awareness on hazardous nature of off-grid solar systems e-waste to both consumers and institutions of governance.Furthermore,there is little enforcement of the general regulations in addition to inadequate management infrastructures.This calls for development of effective off-grid solar e-waste management policies and regulations within the backdrop of the rising uptake of off-grid solar energy systems in Kenya.

High-pressure natural gas pipeline transportation has the advantages of large gas transmission capacity, low transportation cost, whereas physical explosion of the pipeline may cause casualties and property losses. Based on the theory of conversion of physical explosion energy and TNT equivalent of high-pressure natural gas pipeline, this research uses HyperMesh software to build a physical explosion model of high-pressure natural gas pipeline. The crater generated by physical explosion of pipeline was simulated and analyzed using LS-DYNA software. It can be concluded that the crater building process was completed in 0.038 s, forming spindle shaped cavity crater (9.27 m×4.86 m×3.0 m). The overpressure value of the shock wave at the center of the ground burst is 6.64 MPa according to the simulation of the generation and attenuation process of the physical explosion shock wave. Based on Sadovsky’s research conclusion on shock wave attenuation, the minimum distance required for shock wave attenuation on the ground to the safe overpressure value (0.02 MPa) is 33 m. The research conclusion is of great significance to the prediction of the consequences of physical explosion damage of high-pressure natural gas pipeline and the determination of the safe laying scheme.

In this paper, the vector extension operation is proposed to replace the de Boor-Cox formula for a fast algorithm to B-spline basis functions. This B-spline basis function based on vector extending operation is implemented in the class and shape transformation (CST) parameterization method in place of the traditional Bezier polynomials to enhance the local ability of control and accuracy to represent an airfoil shape. To calculate the k-degree B-spline function’s nonzero values, the algorithm can improve the computing efficiency by 2k+1 times.

Compared with traditional technology, bonding technology is more suitable for civil structure reinforcement because of its cost-efficiency and superior mechanical properties. As one of the simplest forms of adhesive joints, numerous studies have been conducted on the performance of single-lap joints (SLJs). However, research on the long-term performance of SLJs requires better organization and comprehension. This paper aims to investigate the long-term performance and optimization design of SLJs. The main factors influencing the long-term performance of SLJs from both material and component levels are discussed. The moisture diffusion mechanisms of bulk adhesives and the degradation mechanisms of SLJs are explored. Moreover, the optimization design of SLJs focuses on evaluating the overlap length, adhesive layer thicknesses, and changes in adhesives along the overlap length based on available literature. This paper can be employed to improve the shear strength and long-term performance of SLJs and to provide insights into their challenges and prospects.

Epilepsy is a condition that disrupts normal brain function and sometimes leads to seizures, unusual sensations, and temporary loss of awareness. Electroencephalograph (EEG) records are commonly used for diagnosing epilepsy, but traditional analysis is subjective and prone to misclassification. Previous studies applied Deep Learning (DL) techniques to improve EEG classification, but their performance has been limited due to dynamic and non-stationary nature of EEG structure. In this paper, we propose a multi-channel EEG classification model called LConvNet, which combines Convolutional Neural Networks (CNN) for spatial feature extraction and Long Short-Term Memory (LSTM) for capturing temporal dependencies. The model is trained using open source secondary EEG data from Temple University Hospital (TUH) to distinguish between epileptic and healthy EEG signals. Our model achieved an impressive accuracy of 97%, surpassing existing EEG classification models used in similar tasks such as EEGNet, DeepConvNet and ShallowConvNet that had 86%, 96% and 78% respectively. Furthermore, our model demonstrated impressive performance in terms of trainability, scalability and parameter efficiency during additional evaluations.

The main challenge faced by many mechanical engineering educators is the implementation of real solutions during their courses. One alternative can be a project-based learning, where the students can be engaged in the development and analysis process currently applied in the industry. This kind of teaching process not only can be used to improve the quality of teaching-learning process but also the students can have opportunities to solve real engineering problem. This paper therefore reports a project-based learning implemented in mechanical engineering courses given in bachelor´s and master’s degree. The component under evaluation has been selected considering the student’s interest, this criterion was also taken to involve several students into a real project process to their learning development. During the semester have been delivered activities to solve the same problem using different approaches based on student´s skills. This procedure can be replicated for students and teachers by following steps. To begin this process, the first step is present the theoretical basis for modal analysis. The second step is to apply theorical knowledge to structure a numerical finite element model. Then, it is used Hypermesh, Optistruct and HyperView software to solve and simulate. The final step was to perform experimental using a three-dimensional scanning vibrometer on 60 samples. It is well noted that the implementation of engineering software commonly used at the industry would increase students’ confidence. This allows students to perform real problem-solving activities to develop outcomes as establish goals, plan task, meet deadlines. Therefore, this paper shows an engineering solution process to provide a learning alternative to teach the modal finite method solutions correlation with experimental solutions.

Engineering systems have been designed to facilitate society. These systems can be seen everywhere in our daily lives ranging from electrical systems to mechanical systems, and from bio-medical systems to industrial systems. With tight coupling with information and communication technology (ICT), these engineering systems can be even controlled and monitored remotely. These systems are supported massively with sensors through which they capture enormous data, which is then used to improve the performance of the systems. Moreover, complex processes are involved in the overall functioning of these engineering systems. The management of data and processes within these engineering systems has been done through traditional ways such as database management systems or spread sheets, however, involvement of multiple parties makes these engineering systems more complex to operate, track, and audit. Blockchain technology has the potential to replace traditional database systems and offers a level of trust in an untrusted environment. With features of immutability, traceability, transparency, availability, and decentralization, blockchain technology is a good match for engineering systems. Blockchain technology can help in supply chain in these engineering systems, but it can also be used to facilitate data, process, and parties. Considering enormous applications of blockchain technology in engineering systems, this Special Issue in Wiley Engineering Reports invited for the original scientific and technical contributions.

Current study examined the magnetohydrodynamic (MHD) Prandtl nanofluid of a thermal double-diffusive flow through an exponentially vertical surface in association with heat generation, and thermophoresis effect. The novelty of this study is due to the analysis of Prandtl nanofluid model with Soret mechanism and chemically responding fluids. The fluid flow phenomenon is characterized by nonlinear coupled differential equations involving two or more independent variables. A suitable numerical technique is used to handle the set of governing equations along with a stability and convergence analysis. According to recent study, the fluid velocity increases since all the parameters are set to higher levels. For the various parametric values, isotherms and streamlines have been explored. This suggested model is beneficial since it can significantly advance the domains of thermal and industrial engineering. For instance, thermal radiation is crucial in designing sophisticated energy-transformed systems that operate at high temperatures. On the other hand, the phenomenon of Soret is useful in separating isotopes in chemical engineering. These studies have several applications in the manufacturing and biomedical fields, petrochemical industries, automobiles, medical sciences, and various production processes in industries.

Bilge and oily water (BOW) during vessel’s operation are the most large-tonnage type of waste and for their treatment all ships, in accordance with regulatory requirements [14], have to be equipped with special equipment – oily water separators. At sea vessel’s operating conditions three main directions of BOW cleaning are now used: physical, chemical and biological. The analysis of BOW separation methods based on these three directions has shown that it is very difficult to obtain secondary petrochemical products. In the article authors offer a new method for BOW separation which is based on the use of a hydrodynamic process of supercavitation with artificial ventilation of the cavitational cavern. With local origin in the flow of a supercavitating cavern, there will always be saturated water vapor inside of it. The process of permanent water vapor selection from the cavern will ultimately contribute to the production of highly concentrated mixture of secondary petroleum products from initial mixture of BOW. During the study of BOW separation process it was found that decreasing of the working pressure inside the working chamber of the cavitation separator have to be always compensated by an increase in the temperature of the processed multiphase flow.