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This is a high-level study into the validation of a unified electric power and communications architecture for modern spacecraft systems. We leverage from blending the European Cooperation for Space Standardisation (ECSS) SpaceWire and the IEEE 802.3 Power over Ethernet (PoE) standards for a common onboard power and communications interface. The focus of the work has been communication performance. The requirements from the protocols of both standards were analysed and combined to create a full protocol stack for SpaceWire PoE. The stack is implemented on an embedded platform represented as a proof-of-concept SpaceWire PoE system. The results of functional testing demonstrate SpaceWire PoE as a valid solution that meets the requirements of both protocols. For the 100 Mb/s links, the... |
In this study, timber column–sill joints strengthened with carbon fiber-reinforced plastic (CFRP) plates using bonds and screws were subjected to loading tests. Twelve joint specifications were considered depending on different combinations of the CFRP plate surface finish and thickness and the type of bond, and the corresponding effects on the load–displacement behavior of the joints were investigated. Three failure modes were observed in addition to the peeling of the CFRP plate. The specimens that failed owing to screw tear out and screw head pull-through in the CFRP plate or splitting of the sill showed load–displacement curves of a similar shape. |
The paper industry manufactures corrugated cardboard packaging, which is unassembled and stacked on pallets to be supplied to its customers. Human operators usually classify these pallets according to the physical features of the cardboard packaging. This process can be slow, causing congestion on the production line. To optimise the logistics of this process, we propose a visual recognition and tracking pipeline that monitors the palletised packaging while it is moving inside the factory on roller conveyors. Our pipeline has a two-stage architecture composed of Convolutional Neural Networks, one for oriented pallet detection and recognition, and another with which to track identified pallets. |
Since the nineteenth century, reinforced concrete was evolved as a crucial material for construction. This popular composite material is broadly used in different building typologies. However, the decaying of steel rebar due to corrosion is identified as a hindrance that can affect the quality of reinforced concrete structures. In reference to this, the glass fiber-reinforced polymer (GFRP) bar is essential because of corrosion-resistant properties. The researchers performed various tests and numerical analysis to know the response of GFRP-reinforced flexural members in shear and bending. Based on studies over the last decade, this study critically analyzes the response of flexural member reinforced using glass fiber-reinforced polymer (FRP) bars. Understanding the behavior of the F... |
The collaborative robots (cobots) are increasingly being utilized in industries due to the advancement in the field of robotic technology and also due to the increase in labor costs. The cobots on the assembly line can be utilized to complete the tasks independently or assist the workers to complete the tasks. This study considers the U-shaped assembly line balancing problem with cobots, where several cobots with different purchasing costs are selected under the budget constraint. Three mixed-integer programming models are formulated to optimize the cycle time, and the built models are capable of solving the small-sized instances optimally. |
The construction industry is plagued with significant construction and demolition waste (C&DW) generated during various phases of construction projects. This waste has created a universal, pervasive, and enduring problem globally. To propose practical solutions to resolve this consequential issue, this research adopted a quantitative approach in two stages. The first stage involved an online survey, administrated to 360 methodically selected construction organisations working in Egypt, to evaluate the impact of six main factors on C&DW reduction (C&DWR). The six main factors are as follows: (1) materials procurement measures (MPMR); (2) materials procurement models (MPMO); (3) green building practices (GBPR); (4) legislation (LG); (5) culture and behaviour (CB); and (6) awareness (A... |
In order to demonstrate the relevance of considering Vortex-Induced Vibrations (VIV) in the structural design of marine structures, this study proposes an alternative experimental and analytical approach in wet conditions to measure the fluid–structure interaction in the near field and quantify the viscous damping with measured structural and 3D hydrodynamic accelerations. It was demonstrated that VIV caused and incremented 5.00% of the structural damping coefficient, and the extreme wind loading increased 74% of the offshore monopile’s structural damping, demonstrating the relevance of the high non-linear hydrodynamics effects during selecting parameters into the structural design in offshore applications. |
It is still a challenge to achieve large-area preparation of robust superhydrophobic surfaces with strong mechanical stability. Here, a simple and low-cost method to prepare robust decoupling superhydrophobic coatings on aluminum (Al) alloys substrate has been presented. The superhydrophobicity and robustness of decoupling coatings are realized by structuring surfaces at two different length scales, with nanostructures for superhydrophobicity and microstructures for robustness. This prepared decoupling coating shows promising superhydrophobicity, with water contact angle (CA) of ∼158.4° and roll off angle (RA) of ∼3°. |
A data-driven algorithm is proposed for flow reconstruction from sparse velocity and/or scalar measurements. The algorithm is applied to the flow around a two-dimensional, wall-mounted, square prism. To reduce the problem dimensionality, snapshots of flow and scalar fields are processed to derive POD modes and their time coefficients. Then a system identification algorithm is employed to build a reduced order, linear, dynamical system for the flow and scalar dynamics. Optimal estimation theory is subsequently applied to derive a Kalman estimator to predict the time coefficients of the POD modes from sparse measurements. Analysis of the flow and scalar spectra demonstrate that the flow field leaves its footprint on the scalar, thus extracting velocity from scalar concentration measur... |
This paper focuses on the dynamical analysis of the motion of a new three-degree-of-freedom (DOF) system consisting of two segments that are attached together. External harmonic forces energize this system. The equations of motion (EOM) are derived utilizing Lagrangian equations, and the approximate solutions up to the third order are investigated using the methodology of multiple scales. A comparison between these solutions and numerical ones is constructed to confirm the validity of the analytic solutions. The modulation equations (ME) are acquired from the investigation of the resonance cases and the solvability conditions. The bifurcation diagrams and spectrums of Lyapunov exponent are presented to reveal the different types of the system’s motion and to represent Poincaré maps.... |
