Collection of Engineering

The collection is a repository of open access articles where academic achievements of great importance in engineering science and technology can be disseminated and shared. The collection includes new focus, and updates on central issues; heuristic comments and reviews on major issues, articles, and events; research results, in the form of research articles, reviews, perspectives, short communications regarding critical issues, and so on.

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PROGRESSIVE COLLAPSE AND ROBUSTNESS OF FRAMED STRUCTURES: SIMULATION AND DESIGN
M. E., C. A., C. B.M., A. Calvi

Collection of Engineering (2024). 3

Abstract
We present a framework to investigate progressive collapse and robustness of 2D framed structures, subjected to multiple column removals. Progressive collapse is first simulated with an algorithm based on the Discrete Elements. The possible collapse mechanisms emerging from the simulations constitute the input for an analytical model. The model takes into account the dynamics of the response to the sudden initial damage and, under the hypotheses of ideally plastic or perfectly brittle ruptures, provides upper and lower bounds for the collapse loads and for the progressive collapse resistance. Closed form expressions are obtained, that can be valuable for robustness-oriented design. A novel concept of hierarchy in robustness capacity design emerges, which partly conflicts with anti-seismic capacity design. Strategies of compartmentalization and the influence of the position of the initial damage within the frame are discussed, also taking into account the impacts between falling rubble and horizontal floor slabs.
Abstract
We present a framework to investigate progressive collapse and robustness of 2D framed structures, subjected to multiple column removals. Progressive collapse is first simulated [...]
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Structural and Seismic Design of a Steel Staircase using FEM in compliance with Italian Legislation
A. Calvi

Collection of Engineering (2024). 2

Abstract
Structural analysis is conducted by the displacement method for evaluation of the stress-strain state induced by static loads. The analysis is conducted by the modal analysis and acceleration response spectrum method for the evaluation of the stress-strain state induced by dynamic loads (including seismic loads). Structural analysis is carried out using the finite element method. The above method is based on the schematization of the structure into elements connected only at a set number of points called nodes. The nodes are defined by the three Cartesian coordinates in a global reference system. The unknowns of the problem (within the displacement method) are the displacement components of the nodes referred to the global reference system (translations according to X, Y, Z, rotations around X, Y, Z). The solution of the problem is obtained by a system of linear algebraic equations whose known terms consist of the loads acting on the structure appropriately concentrated at the nodes.
Abstract
Structural analysis is conducted by the displacement method for evaluation of the stress-strain state induced by static loads. The analysis is conducted by the modal analysis [...]
- 0
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Automated Detection of Surface Defects on Razor Blades through Video Analysis
L. Chen

Collection of Engineering (2024). 1

Abstract
In the manufacturing process of razor blades, the presence of surface defects directly impacts their quality and lifespan. Manual detection of these defects is not only inefficient but also susceptible to external interference. To achieve real-time and stable detection of blade defects, a method based on video analysis was proposed in this paper. Raw surface images of the blades were captured using a computer vision system, and binarization was performed using Otsu's algorithm. Subsequently, contours were identified and preliminarily analyzed using the CCL algorithm to obtain Regions of Interest (ROI). The ROI was then sorted, and subtle defects were filtered out through morphological analysis. A mask was obtained by comparing the ROI with a background model constructed based on frame averaging. Through mask analysis, defect types were determined, achieving efficient detection of surface defects on razor blades. Experimental results demonstrated that the proposed method enabled real-time detection of multiple defect types simultaneously.
Abstract
In the manufacturing process of razor blades, the presence of surface defects directly impacts their quality and lifespan. Manual detection of these defects is not only inefficient [...]
- 0
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Excavar para restaurar. Cómo piensa un arqueólogo.
J. Torres-Carbonell, . arqueólogo

Collection of Engineering (2022). 1
- 6
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A Method for Accurate and Efficient Propagation of Satellite Orbits: A Case Study for a Molniya Orbit
R. Flores, M. Burhani, E. Fantino

Alexandria Engineering Journal (2021). Alexandria Engineering Journal (2021) 60, 2661–2676

Abstract
Fast and precise propagation of satellite orbits is required for mission design, orbit determination and payload data analysis. We present a method to improve the computational performance of numerical propagators and simultaneously maintain the accuracy level required by any particular application. This is achieved by determining the positional accuracy needed and the corresponding acceptable error in acceleration on the basis of the mission requirements, removing those perturbation forces whose effect is negligible compared to the accuracy requirement, implementing an efficient and precise algorithm for the harmonic synthesis of the geopotential gradient (i.e., the gravitational acceleration) and adjusting the tolerance of the numerical propagator to achieve the prescribed accuracy level with minimum cost. In particular, to achieve the optimum balance between accuracy and computational performance, the number of geopotential spherical harmonics to retain is adjusted during the integration on the basis of the accuracy requirement. The contribution of high-order harmonics decays rapidly with altitude, so the minimum expansion degree meeting the target accuracy decreases with height. The optimum degree for each altitude is determined by making the truncation error of the harmonic synthesis equal to the admissible acceleration error. This paper presents a detailed description of the technique and test cases highlighting its accuracy and efficiency.
Abstract
Fast and precise propagation of satellite orbits is required for mission design, orbit determination and payload data analysis. We present a method to improve the computational [...]
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Long-Term Orbit Dynamics of Decommissioned Geostationary Satellites
S. Proietti, R. Flores, M. Pontani

Acta Astronautica (2020). AA 8423

Abstract
In nominal mission scenarios, geostationary satellites perform end-of-life orbit maneuvers to reach suitable disposal orbits, where they do not interfere with operational satellites. This research investigates the long-term orbit evolution of decommissioned geostationary satellite under the assumption that the disposal maneuver does not occur and the orbit evolves with no control. The dynamical model accounts for all the relevant harmonics of the terrestrial gravity field at the typical altitude of geostationary orbits, as well as solar radiation pressure and third-body perturbations caused by the Moon and the Sun. Orbit propagations are performed using two algorithms based on different equations of motion and numerical integration methods: (i) Gauss planetary equations for modified equinoctial elements with a Runge-Kutta numerical integration scheme based on 8-7th-order Dorman and Prince formulas; (ii) Cartesian state equations of motion in an Earth-fixed frame with a Runge-Kutta Fehlberg 7/8 integration scheme. The numerical results exhibit excellent agreement over integration times of decades. Some well-known phenomena emerge, such as the longitudinal drift due to the resonance between the orbital motion and Earth’s rotation, attributable to the J2 term of the geopotential. In addition, the third-body perturbation due to Sun and Moon causes two major effects: (a) a precession of the orbital plane, and (b) complex longitudinal dynamics. This study proposes an analytical approach for the prediction of the precessional motion and show its agreement with the (more accurate) orbit evolution obtained numerically. Moreover, long-term orbit propagations show that the above mentioned complex longitudinal dynamics persists over time scales of several decades. Frequent and unpredictable migrations toward different longitude regions occur, in contrast with the known effects due only to the perturbative action of J2
Abstract
In nominal mission scenarios, geostationary satellites perform end-of-life orbit maneuvers to reach suitable disposal orbits, where they do not interfere with operational [...]
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An Automatic Tree Search Algorithm for the Tisserand Graph
D. Sangra`, R. Flores

Alexandria Engineering Journal (2020).

Abstract
The Tisserand graph (TG) is a graphical tool commonly employed in the preliminary design of gravity-assisted trajectories. The TG is a two-dimensional map showing essential orbital information regarding the Keplerian orbits resulting from the close passage by one or more massive bodies, given the magnitude of the hyperbolic excess speed and the minimum allowed pericenter height for each passage. Contours of constant populate the TG. Intersections between contours allow to link consecutive flybys and build sequences of encounters en route to a selected destination. When the number of perturbing bodies is large and many excess velocity levels are considered, the identification of all the possible sequences of encounters through visual inspection of the TG becomes a laborious task. Besides, if the sequences are used as input for a numerical code for trajectory design and optimization, an automated examination of the TG is desirable. This contribution describes an automatic technique to explore the TG and find all the encounter paths. The technique is based on a tree search method, and the intersections between contours are computed using the regula-falsi scheme. The method is validated through comparisons with solutions available in the open literature. Examples are given of application to interplanetary mission scenarios, including the coupling with a trajectory optimizer.
Abstract
The Tisserand graph (TG) is a graphical tool commonly employed in the preliminary design of gravity-assisted trajectories. The TG is a two-dimensional map showing essential [...]
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Reduction of Saturn Orbit Insertion Impulse using Deep-Space Low Thrust
R. Flores

Journal of Guidance, Control, and Dynamics (2020). 43(4): 729-740

Abstract
Orbit insertion at Saturn requires a large impulsive manoeuver due to the velocity difference between the spacecraft and the planet. This paper presents a strategy to reduce dramatically the hyperbolic excess speed at Saturn by means of deep-space electric propulsion. The interplanetary trajectory includes a gravity assist at Jupiter, combined with low-thrust maneuvers. The thrust arc from Earth to Jupiter lowers the launch energy requirement, while an ad hoc steering law applied after the Jupiter flyby reduces the hyperbolic excess speed upon arrival at Saturn. This lowers the orbit insertion impulse to the point where capture is possible even with a gravity assist with Titan. The control-law algorithm, the benefits to the mass budget and the main technological aspects are presented and discussed. The simple steering law is compared with a trajectory optimizer to evaluate the quality of the results and possibilities for improvement.
Abstract
Orbit insertion at Saturn requires a large impulsive manoeuver due to the velocity difference between the spacecraft and the planet. This paper presents a strategy to [...]
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Facing Challenges Together
Z. Zhong, R. Reddy

Engineering (2016).
- 15
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The General Design and Technology Innovations of CAP1400
M. Zheng, J. Yan, S. Jun, L. Tian, X. Wang, Z. Qiu

Engineering (2016). Vol. 2

Abstract
The pressurized water reactor CAP1400 is one of the sixteen National Science and Technology Major Projects. Developed from Chinas nuclear R&D system and manufacturing capability, as well as AP1000 technology introduction and assimilation, CAP1400 is an advanced large passive nuclear power plant with independent intellectual property rights. By discussing the top design principle, main performance objectives, general parameters, safety design, and important improvements in safety, economy, and other advanced features, this paper reveals the technology innovation and competitiveness of CAP1400 as an internationally promising Gen-III PWR model. Moreover, the R&D of CAP1400 has greatly promoted Chinas domestic nuclear power industry from the Gen-II to the Gen-III level.
Abstract
The pressurized water reactor CAP1400 is one of the sixteen National Science and Technology Major Projects. Developed from Chinas nuclear R&D system and manufacturing capability, [...]
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The Shandong Shidao Bay 200 MWe High-Temperature Gas-Cooled Reactor Pebble-Bed Module (HTR-PM) Demonstration Power Plant: An Engineering and Technological Innovation
Z. Zhang, Y. Dong, F. Li, Z. Zhang, H. Wang, X. Huang, H. Li, B. Liu, X. Wu, H. Wang, X. Diao, H. Zhang, J. Wang

Engineering (2016). Vol. 2

Abstract
After the first concrete was poured on December 9, 2012 at the Shidao Bay site in Rongcheng, Shandong Province, China, the construction of the reactor building for the worlds first high-temperature gas-cooled reactor pebble-bed module (HTR-PM) demonstration power plant was completed in June, 2015. Installation of the main equipment then began, and the power plant is currently progressing well toward connecting to the grid at the end of 2017. The thermal power of a single HTR-PM reactor module is 250 MWth, the helium temperatures at the reactor core inlet/outlet are 250/750 °C, and a steam of 13.25 MPa/567 °C is produced at the steam generator outlet. Two HTR-PM reactor modules are connected to a steam turbine to form a 210 MWe nuclear power plant. Due to Chinas industrial capability, we were able to overcome great difficulties, manufacture first-of-a-kind equipment, and realize series major technological innovations. We have achieved successful results in many aspects, including planning and implementing R&D, establishing an industrial partnership, manufacturing equipment, fuel production, licensing, site preparation, and balancing safety and economics, these obtained experiences may also be referenced by the global nuclear community.
Abstract
After the first concrete was poured on December 9, 2012 at the Shidao Bay site in Rongcheng, Shandong Province, China, the construction of the reactor building for the worlds [...]
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Health in an Aging World: What Should We Do?
Y. Wen

Engineering (2016). Vol. 2
- 12
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Sustainable Management of Water Resources
Y. Qian

Engineering (2016). Vol. 2
- 26
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Design and R&D Progress of China Lead-Based Reactor for ADS Research Facility
Y. Wu

Engineering (2016). Vol. 2

Abstract
In 2011, the Chinese Academy of Sciences launched an engineering project to develop an accelerator-driven subcritical system (ADS) for nuclear waste transmutation. The China Lead-based Reactor (CLEAR), proposed by the Institute of Nuclear Energy Safety Technology, was selected as the reference reactor for ADS development, as well as for the technology development of the Generation IV lead-cooled fast reactor. The conceptual design of CLEAR-I with 10 MW thermal power has been completed. KYLIN series lead-bismuth eutectic experimental loops have been constructed to investigate the technologies of the coolant, key components, structural materials, fuel assembly, operation, and control. In order to validate and test the key components and integrated operating technology of the lead-based reactor, the lead alloy-cooled non-nuclear reactor CLEAR-S, the lead-based zero-power nuclear reactor CLEAR-0, and the lead-based virtual reactor CLEAR-V are under realization.
Abstract
In 2011, the Chinese Academy of Sciences launched an engineering project to develop an accelerator-driven subcritical system (ADS) for nuclear waste transmutation. The China [...]
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The Progress and Grand Challenge of Urbanization in China
X. Kuangdi

Engineering (2016). Vol. 2
- 327
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HPR1000: Advanced Pressurized Water Reactor with Active and Passive Safety
J. Xing, D. Song, Y. Wu

Engineering (2016). Vol. 2

Abstract
HPR1000 is an advanced nuclear power plant (NPP) with the significant feature of an active and passive safety design philosophy, developed by the China National Nuclear Corporation. On one hand, it is an evolutionary design based on proven technology of the existing pressurized water reactor NPP, on the other hand, it incorporates advanced design features including a 177-fuel-assembly core loaded with CF3 fuel assemblies, active and passive safety systems, comprehensive severe accident prevention and mitigation measures, enhanced protection against external events, and improved emergency response capability. Extensive verification experiments and tests have been performed for critical innovative improvements on passive systems, the reactor core, and the main equipment. The design of HPR1000 fulfills the international utility requirements for advanced light water reactors and the latest nuclear safety requirements, and addresses the safety issues relevant to the Fukushima accident. Along with its outstanding safety and economy, HPR1000 provides an excellent and practicable solution for both domestic and international nuclear power markets.
Abstract
HPR1000 is an advanced nuclear power plant (NPP) with the significant feature of an active and passive safety design philosophy, developed by the China National Nuclear Corporation. [...]
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Responding to Global Changes as a Community of Common Destiny
X. Du

Engineering (2016). Vol. 2
- 16
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Fitting on the Earth: Challenges of Carbon and Nitrogen Cycle to Preserve the Habitability of the Planet
R. Socolow

Engineering (2016). Vol. 2
- 30
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Informatics: The Frontier of Innovation in Health and Healthcare
M. Coye

Engineering (2016). Vol. 2
- 13
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Human-Centered Mobility: A New Approach to Designing and Improving Our Urban Transport Infrastructure
D. Mitchell, S. Claris, D. Edge

Engineering (2016). Vol. 2
- 762
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PROGRESSIVE COLLAPSE AND ROBUSTNESS OF FRAMED STRUCTURES: SIMULATION AND DESIGN

Structural and Seismic Design of a Steel Staircase using FEM in compliance with Italian Legislation

Automated Detection of Surface Defects on Razor Blades through Video Analysis

Excavar para restaurar. Cómo piensa un arqueólogo.

A Method for Accurate and Efficient Propagation of Satellite Orbits: A Case Study for a Molniya Orbit

Long-Term Orbit Dynamics of Decommissioned Geostationary Satellites

An Automatic Tree Search Algorithm for the Tisserand Graph

Reduction of Saturn Orbit Insertion Impulse using Deep-Space Low Thrust

Facing Challenges Together

The General Design and Technology Innovations of CAP1400

The Shandong Shidao Bay 200 MWe High-Temperature Gas-Cooled Reactor Pebble-Bed Module (HTR-PM) Demonstration Power Plant: An Engineering and Technological Innovation

Health in an Aging World: What Should We Do?

Sustainable Management of Water Resources

Design and R&D Progress of China Lead-Based Reactor for ADS Research Facility

The Progress and Grand Challenge of Urbanization in China

HPR1000: Advanced Pressurized Water Reactor with Active and Passive Safety

Responding to Global Changes as a Community of Common Destiny

Fitting on the Earth: Challenges of Carbon and Nitrogen Cycle to Preserve the Habitability of the Planet

Informatics: The Frontier of Innovation in Health and Healthcare

Human-Centered Mobility: A New Approach to Designing and Improving Our Urban Transport Infrastructure

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