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"Design criteria"
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Biochar imparted constructed wetlands (CWs) for enhanced biodegradation of organic and inorganic pollutants along with its limitation
The remediation of polluted soil and water stands as a paramount task in safeguarding environmental sustainability and ensuring a dependable water source. Biochar, celebrated for its capacity to enhance soil quality, stimulate plant growth, and adsorb a wide spectrum of contaminants, including organic and inorganic pollutants, within constructed wetlands, emerges as a promising solution. This review article is dedicated to examining the effects of biochar amendments on the efficiency of wastewater purification within constructed wetlands. This comprehensive review entails an extensive investigation of biochar’s feedstock selection, production processes, characterization methods, and its application within constructed wetlands. It also encompasses an exploration of the design criteria necessary for the integration of biochar into constructed wetland systems. Moreover, a comprehensive analysis of recent research findings pertains to the role of biochar-based wetlands in the removal of both organic and inorganic pollutants. The principal objectives of this review are to provide novel and thorough perspectives on the conceptualization and implementation of biochar-based constructed wetlands for the treatment of organic and inorganic pollutants. Additionally, it seeks to identify potential directions for future research and application while addressing prevailing gaps in knowledge and limitations. Furthermore, the study delves into the potential limitations and risks associated with employing biochar in environmental remediation. Nevertheless, it is crucial to highlight that there is a significant paucity of data regarding the influence of biochar on the efficiency of wastewater treatment in constructed wetlands, with particular regard to its impact on the removal of both organic and inorganic pollutants.
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Journal Article
Automatic Design of Robot Swarms under Concurrent Design Criteria: A Study Based on Iterated F‐Race
Automatic design is an appealing approach to realizing robot swarms. In this approach, a designer specifies a mission that the swarm must perform, and an optimization algorithm searches for the control software that enables the robots to perform the given mission. Traditionally, research in automatic design has focused on missions specified by a single design criterion, adopting methods based on single‐objective optimization algorithms. In this study, we investigate whether existing methods can be adapted to address missions specified by concurrent design criteria. We focus on the bi‐criteria case. We conduct experiments with a swarm of e‐puck robots that must perform sequences of two missions: each mission in the sequence is an independent design criterion that the automatic method must handle during the optimization process. We consider modular and neuroevolutionary methods that aggregate concurrent criteria via the weighted sum, hypervolume, or l2 $l^{2} $ ‐norm. We compare their performance with that of Mandarina, an original automatic modular design method. Mandarina integrates Iterated F‐race as an optimization algorithm to conduct the design process without aggregating the design criteria. Results from realistic simulations and demonstrations with physical robots show that the best results are obtained with modular methods and when the design criteria are not aggregated. The study explores a novel approach to the automatic design of robot swarms using a bi‐criteria optimization method called Mandarina. It compares Mandarina with other methods, focusing on performance across sequential tasks. The results highlight Mandarina's effectiveness in generating robot behavior that balances multiple design criteria without needing human intervention, showcasing its potential for complex missions.
Journal Article
Smoke Control Strategy and Design Criterion in Tunnel Fire Hazards Using Point Extraction Ventilation: Experimental Analysis and Theoretical Modeling
The hot and toxic smoke is a major reason for deaths and injuries in tunnel fire hazards, therefore, it is of vital importance for safe evacuation to effectively control the smoke. This paper proposed a smoke control strategy, i.e., completing smoke extraction, and developed the design criterion of exhaust rate based on small-scale experiments and theoretical analysis. The heat release rate (HRR), damper length, and interval were considered. Experimental results showed the critical exhaust rate for completing smoke extraction rose with the increase in HRR and declined with a growing damper interval. Besides, it first rapidly decreased and then turned to be smooth with rising damper length. Subsequently, the ratio of the suction force, Fd to the force, Fs was adopted to determine the completing smoke extraction using force analysis. The results illustrated that the HRR and damper interval barely affect the relative magnitude between the suction force, Fd, and the force, Fs. It was linearly dependent on the dimensionless damper length and then exponentially grew. The critical length of the damper was 0.1 m. Finally, a prediction model was established, and the evaluated results deviated from the experimental data within 15%.
Journal Article
Multi-Objective Optimal Design of Detention Tanks in the Urban Stormwater Drainage System: Framework Development and Case Study
Detention tank plays an important role in the flooding control in the downstream areas of the urban stormwater drainage system (USDS) during the wet weather seasons. For complex watersheds with specific local flooding control policies, the conventional optimization and design methods are found to be not sufficient for effectively and optimally locating and sizing appropriate detention tanks any more. This paper investigates the optimal design of detention tanks under the constraints of local flooding control criteria, with the aim to develop an efficient and robust method and framework for the design of detention tank network. Coupled with the SWMM-based hydraulic simulation, a modified particle swarm optimizer is adopted to find out non-dominated solutions to minimize both the engineering cost and flooding risks by taking the local design criteria into consideration for the more realistic local engineering application. To validate the proposed method, a real-life case in SA city in China is taken for example to obtain optimal layout and sizes of the detention tank network under different construction factors and design conditions. Different rainfall return periods are also tested to guarantee the robustness of the optimal solutions. The results of this study confirm the feasibility and validity of the proposed methodological framework for multi-objective optimal design of detention tanks in the USDS.
Journal Article
Design method and driving optimization of origami-inspired single-layer truss structures for parabolic cylindrical mesh reflector antennas
Deployable parabolic cylindrical antennas with lightweight and high deploy/fold ratio are a research hotspot in aerospace. Most of the deployable structures of parabolic cylindrical antennas are double-layer truss structures, which are heavy and oversized in folded volume. The 2D origami-inspired structure is a typical single-layer deployable structure, including multiple origami configurations that provide various strategies for designing single-layer deployable structures. This study proposes a design method for origami-inspired single-layer truss structures applied to deployable parabolic cylindrical mesh reflector antennas. Unlike the widely researched thick-panel origami structure, we adopt the strategy of equating the creases in the origami model as links with constant length, and the vertices are regarded as hinges. The design criteria for an origami-inspired single-layer truss structure are researched and summarized by analyzing the engineering issues during design. Based on this design method, a single-layer deployable truss applied to a parabolic cylindrical antenna is presented. An optimization model of the antenna driving components is established to ensure that the antenna can deploy appropriately on the basis of the co-simulation of MATLAB and finite element software Abaqus. The optimization results are validated through software simulation and prototype test. The work presented in this paper can broaden the application of origami-inspired structures and provide a reference for the design of parabolic cylindrical antennas or curved surface mechanisms.
Journal Article
Protecting larval fish at water intakes: hydraulic and biological evidence for the effectiveness of modern fish-protection screens
Water intakes entrain large numbers of fish larvae in waterways where drift coincides with large-scale extraction. While modern fish-protection screens can reduce these losses, many are not designed for larvae and were developed or evaluated primarily for juveniles and adults. This study evaluated the effectiveness of Australia's fish screen design criteria (which specify a maximum approach velocity of 0.1 m s−¹ and slot widths of 2–3 mm) for protecting drifting larval Murray cod (Maccullochella peelii). Larvae were tested in a large flume under combinations of approach velocity (0.1 or 0.2 m s−¹), slot width (2 or 3 mm), and proximity. Entrainment rose sharply with velocity; slot size had a smaller interactive effect. The most protective combination (0.1 m s−¹ and 2 mm) reduced entrainment by up to 94% relative to unscreened conditions. Three-dimensional flow measurements helped explain how velocity vectors interact to influence larval fate. The results demonstrate that Australia's current standards, although developed for juveniles, can provide strong larval protection when strictly followed, but that even modest departures can sharply increase risk. More broadly, since the criteria tested here are less conservative than those adopted in many other countries, where empirical evidence on larval behaviour does not exist, targeted research could determine whether existing guidelines warrant revision.
Journal Article
Nonspherical photonic scatterers and design criterion for efficient passive daytime radiative cooling
Passive daytime radiative cooling (PDRC) exhibits efficient cooling performance to reduce global fossil energy consumption and has attracted enormous interest. An efficient PDRC technology for achieving daytime subambient cooling is supposed to exhibit ultra-high solar reflectivity and infrared emissivity within atmospheric windows, among which ultra-high solar reflectivity is the principal property. In most PDRC technologies, spherical particles are selected as scatterers to achieve high solar reflectivity because the Mie scattering effect of spherical scatterers can provide a high scattering efficiency. However, the weak backward scattering of spherical scatterers remains a drawback. In this study, several nonspherical scatterers with strong backward scattering are introduced and researched systematically. The numerical analysis results indicate that pyramidal scatterers provide the strongest backward scattering and square/circular scatterers exhibit the highest scattering efficiency. Besides, by considering scattering efficiency and asymmetry factor comprehensively, a dimensionless evaluation parameter is proposed, which can be employed as a quantitative design criterion to achieve the optimal-object-oriented designing of superior scatterers. This work can provide an innovative strategy for designing efficient passive daytime radiative cooling materials.
Journal Article
A Systematic Approach towards the Integration of Initial Airworthiness Regulatory Requirements in Remotely Piloted Aircraft System Conceptual Design Methodologies
The regulatory framework of Remotely Piloted Aircraft Systems (RPASs) has recently experienced an extraordinary evolution. This article seeks to improve the integration of certification considerations in RPAS conceptual design approaches so as to enhance the safety, certifiability and competitiveness of their resulting designs. The first part of the research conducts a two-stage analysis of contemporary regulations related to an RPAS’s initial airworthiness. In the first stage, the broad international regulation paradigm is evaluated attending to a set of criteria that are tightly related to both airworthiness and design considerations. The second stage keeps the most promising documents from a design–integration standpoint, which are assessed according to their applicability considering both design and operational aspects. The results of this analysis provide insights regarding the main issues in airworthiness design criteria extraction and integration in design methodologies. To aid the designer in surmounting these challenges, a flexible procedure named DECEX is developed. Considering the documents and findings from the survey, and attending to the scope of the design methodology being developed, it aids in establishing a complete regulatory document corpus and in comparing and extracting the applicable airworthiness design criteria. Two case studies for different RPAS types are conducted to demonstrate its application.
Journal Article
Rigid-Body Dynamics Modeling and Core Functional Component Selection for Heavy-Duty Industrial Robots
The selection and design of core functional components are a primary task in the engineering design of heavy-duty industrial robots, in which joint constraint forces and moments act as essential indicators for component selection. This paper proposes a general inverse rigid-body dynamics model for serial kinematic chains that explicitly incorporates joint constraint forces and moments. On this basis, a rigid-body dynamics model for heavy-duty industrial robots is established, which fully considers inertia, gravity, and balancing forces of the balance system, and is verified through dynamic simulations. Corresponding selection and design criteria are then formulated for joint motors, RV reducers, and balance systems. Simulation analyses and prototype full-load tests jointly confirm that the robot meets the 1000 kg load capacity requirement and validate the effectiveness of the proposed selection and design criteria. This study provides a reliable theoretical and engineering reference for the design and development of heavy-duty industrial robots.
Journal Article