Optimal Distribution Research Articles

Sustainability in bridge design—investigation of the potential of topology optimization and additive manufacturing on a model scale

AbstractBridge design represents a typical challenge in civil engineering. The high material usage in combination with the considerable construction effort makes their longevity a strongly desirable property. A mechanically efficient design contributes to optimum load distribution within the structure. Numerical topology optimization represents a valuable tool that can be applied for form finding of load‐appropriate structural layouts within a predefined design‐space. This study takes application of topology optimization to bridge design into focus. Different bridge types are designed using topology optimization considering self‐weight based on a routine that was presented in a previous work. The bridge designs are examined in detail and compared to already existing bridges with regard to the requirements of modern structures. In order to demonstrate manufacturability of the designs, they are realized on a model scale using an additive manufacturing (am) technique in the powder bed. The knowledge gained from this small scale consideration is transferred to the context of civil engineering to highlight the potential of AM in realization of resource efficient construction.

Exploring Asymmetric Lens–Total Internal Reflection (AL–TIR) Optics for Uniform Ceiling Illumination in Interior Lighting

This study presents a significant advancement in LED interior lighting through the development and application of Asymmetric Lens–Total Internal Reflection (AL–TIR) optics, with a focus on enhancing lighting uniformity and indoor comfort by simulating sky-like lighting distribution. AL–TIR technology employs asymmetric lenses combined with total internal reflection to efficiently redirect and spread light, achieving a controlled and even ceiling illumination suitable for various interior applications. This research explored the establishment of ideal luminous intensity curves, devised practical AL–TIR optical designs through numerical calculations, and conducted extensive simulations to assess performance in typical indoor environments. Our findings demonstrated substantial improvements in lighting uniformity, with the AL and AL–TIR systems achieving direct illuminance uniformities of 0.78 and 0.83, respectively, compared to traditional tube LEDs at 0.25. These results, validated in several office rooms, highlight the efficacy of AL–TIR optics in revolutionizing indoor lighting design by balancing optimal lighting distribution with occupant comfort and well-being.

Assessing the bioenergy potential of abandoned cropland in China: Toward an optimal distribution of bioenergy crops

Bioenergy has gained wide attention due to its potential to reduce fossil fuel consumption and greenhouse gas emissions. Abandoned cropland is a promising option for cultivating bioenergy crops, as it does not compete with food production. The vast amount of abandoned cropland in China provides extensive opportunities for the development of bioenergy. However, the bioenergy potential of China's abandoned cropland remains unclear. In this study, we identified abandoned cropland in China for the period of 2000–2020. Based on this, we estimated the bioenergy potential from conventional food crops (maize and wheat), and perennial bioenergy crops (miscanthus and switchgrass), on the abandoned cropland in China. We optimized the planting of conventional food and two perennial bioenergy crops by maximizing crop yield and accounting for water limits. The results show that 29.49 Mha of abandoned cropland was found in the past twenty years. Spatially, it was mainly located in eastern China with relatively high soil quality, in contrast to that in the U.S. and Europe. By optimizing the crop distribution on abandoned cropland, the bioenergy potential primarily shows a spatial distribution of higher potential in the south and lower potential in the north, with a total yield reaching 9.52 EJ. This is approximately 1.43 times higher than that of solely cultivating miscanthus and 8.28 times that of wheat. This potential accounts for 6 % of China's total primary energy consumption in 2022 and 7.66 % of the carbon emission peak target for 2030. It holds significant importance for the national emission reduction strategy. These findings highlight the immense bioenergy potential of abandoned cropland, providing support for the development of bioenergy.

Enhancing Flexibility and Reliability in Smart Distribution Networks: A Self-Healing Approach

This paper presents a pioneering approach that integrates a Self-Healing System through a Smart Distribution Network, which employs a two-step implementation of a comprehensive Energy Management algorithm and a multi-agent system with an autonomous distributed regeneration method. The novel method improves network operation through optimized management of local microgrids, which include diverse components comprising renewable energy sources, electric vehicle charging infrastructure, and energy storage systems. The first phase concentrates on minimizing network operation costs by adhering to system utilization restrictions and optimal load distribution, while the second phase addresses the optimization of regeneration processes, which decreases discrepancies between recoverable priority loads and switching operations. The evaluation introduces a stochastic programming approach to model and manage uncertainties, and utilizes the Kantorovich method and the roulette wheel mechanism to improve reliability. ...

Dynamic Energy Management and Control of Networked Microgrids based on Load to Grid Services and Incentive-Based Demand Response Programs: A Multi-Agent Deep Reinforcement Learning Approach

This study has presented the energy management paradigm in a networked microgrid structure based on L2G services and considering incentive-based load response (IBDR) programs and energy market requirements to reduce operating costs, control and restore voltage and frequency index, providing the benefits of subscribers and distribution system operators. In this study, multi-objective functions such as optimal operation based on IBDR structure and energy market requirements, risk assessment, and L2G service approach are configured in the framework of central and local controllers. Optimal operation and risk assessment are analyzed by a multi-task learning algorithm based on multi-objective function and L2G service policies are evaluated based on multi-agent deep reinforcement learning. Control policies are sent by the communication system to the components affecting the optimal power distribution as well as the voltage and frequency controllers. L2G services have been evaluated in different scenarios such as plug-and-play operating conditions, load fluctuations, and operating in island mode. The results of optimal operation based on L2G services show that the IBDR program implementation reduces the total operation cost by 21%. Also, the total operating cost of the proposed framework is 13.97% less than the RL method and 27.8% less than the ANN method.

Predicting the Potential Distribution of the Endangered Pyrethrum tatsienense in China Using an Optimized Maxent Model Under Climate Change Scenarios.

Climate change can significantly impact the ecological suitability and diversity of species. Pyrethrum tatsienense, a critically endangered species in China, requires a thorough understanding of its habitat distribution and the environmental factors that affect it in the context of climate change. The Maxent algorithm was used to examine the key factors influencing the distribution of P. tatsienense in China, using data from 127 species occurrences and environmental variables from the Last Interglacial (LIG), Last Glacial Maximum (LGM), Mid-Holocene (MH), current, and future scenarios. The Maxent model was optimized utilizing the R package ENMeval, providing the most accurate predictions for suitable habitats across various scenarios. Results show that suitable regions for P. tatsienense encompass approximately 15.02% (14.42 × 105 km2) of China, predominantly on the Qinghai-Tibetan Plateau. The mean UV-B of the highest month (UVB3: 39.7%), elevation (elev: 28.7%), and the warmest season of precipitation (Bio18: 17.4%) are the major limiting factors for suitable habitat. The optimal species distribution ranges are identified as > 7500 J m-2 day-1 for UVB3, 2700-5600 m for elev, and 150-480 mm for Bio18. Predictions for the historical climate indicate the presence of refugia at the junction of Sichuan, Tibet, and Qinghai. The MH predictions show an increase in climatic suitability for P. tatsienense compared to the LIG and LGM, with an expansion of suitable areas westward. Future climate change scenarios indicate that the potential suitable habitat for P. tatsienense is expected to increase with increasing radiative forcing, with higher latitude regions becoming new marginally suitable habitats. However, predicted environmental changes in western Tibet may drive the loss of highly suitable habitats in the future. These findings enhance our understanding of how environmental factors impact the habitat suitability of P. tatsienense and provide valuable insights for developing effective management and conservation strategies for this important species.

Research on energy interactive operation optimization strategy of multi-energy network with integrated energy based on cooperative game

Abstract Integrated energy includes multi-energy networks such as electricity, gas, cold, and heat. Horizontal multi-energy coordination and vertical source network storage load interaction can effectively support large-scale new energy consumption. In this paper, a multi-energy flow model of the integrated energy multi-energy network is constructed, an optimization model of energy sharing and mutual benefit of the multi-energy network is established based on Nash negotiation, and then the model is solved to obtain the optimal distribution scheme of cooperation benefits. Finally, a numerical example is given to verify the proposed energy sharing and mutual benefit method. The results show that the total power generation cost of each park is reduced by 27%, and the profit distribution of each park is more reasonable.

The output flexibility optimization control of load-side wind turbine considering client demand response

Abstract This study focuses on optimizing the output flexibility control of load-side wind turbines considering client demand response. Considering the potential and role of client demand response, a load-side wind turbine output objective function was constructed, client demand response constraints were designed, and a two-layer model for flexible optimization control of load-side wind turbine output was constructed. The top is the power allocation hierarchy, and the core objective of this layer is to achieve power optimization distribution of wind turbines under various constraint conditions. The lower layer is the frequency control layer, which optimizes and controls the dynamic frequency of load-side wind turbine output. The experimental results show that the optimized control strategy not only enhances the efficiency of wind turbines, but also effectively reduces energy loss and enhances the stability and reliability of the power grid. Through precise calculation and real-time adjustment of the double-layer model, we can more accurately predict and control the output of wind turbines, thereby ensuring the supply-demand balance of the power grid and reducing potential risks caused by frequency fluctuations and power offsets.

A Recursive Optimization Approach for Buffer Allocation in Large Production Lines

Buffer allocation is a critical issue in the design stage of manufacturing systems, as buffer capacities may have a great impact on system performance. In this paper, we consider the problem of minimizing the total buffer capacity of a flow line to achieve a desired production rate. A recursive optimization approach is proposed to solve the problem in large production lines. Instead of optimizing a long line directly, the proposed approach decomposes it into two sub-lines, optimizes them recursively, and combines their solutions to find the optimal buffer distribution of the original line. Two different recursive algorithms are developed and their performance is demonstrated by comparing them with a gradient search algorithm. The numerical results show that the recursive algorithms are almost as accurate as the gradient algorithm, but much more efficient, especially for large production lines.

Novel PCA-Based Lower-Dimensional Remapping of the Solution Space for a Genetic Algorithm Optimization: Estimating the Director Distribution in LC-Based SLM Devices

This work introduces a novel computational approach based on Principal Component Analysis (PCA) for dimensionality reduction of the solution space in optimisation problems with known linear interdependencies among solution variables. By creating synthetic datasets with deliberately engineered properties and applying PCA, the solution space’s remapping significantly reduces its dimensionality, leading to faster computation and more robust convergence in optimisation processes. We demonstrate this method by integrating it with a Genetic Algorithm (GA) for solving the optimal director distribution in liquid crystal (LC) devices, specifically addressing 2D and complex 3D spatial light modulator (SLM) structures such as twisted nematic liquid crystals (TN-LC) and parallel-aligned liquid crystal on silicon (PA-LCoS), respectively. The phase profiles obtained from the director vector distributions for horizontal and vertical high-frequency binary phase gratings closely match the theoretical values derived from minimising the traditional elastic Frank–Oseen functional via Euler–Lagrange equations. Beyond this specific application, our method offers a general framework for reducing computational complexity in optimisation problems by directly reducing the dimensionality of the solution space. This approach is applicable across various optimisation scenarios with well-known linear interdependencies among solution variables, enabling significant reductions in computational costs and improvements in robustness and convergence.

An Automated Computational Fluid Dynamics Workflow for Simulating the Internal Flow of Race Car Radiators

In this article, we present a software tool developed in Python, named T-WorkFlow. It has been devised to meet some of the design needs of Tatuus Racing S.p.a., a leading company in the design and production of racing cars for the FIA Formula 3 Regional and Formula 4 categories. The software leverages the open-source tools OpenFOAM and FreeCAD to fully automate the fluid dynamics simulation process within car radiators. The goal of T-WorkFlow is to provide designers with precise and easily interpretable results that facilitate the identification of the geometry, ensuring optimal flow distribution in the radiator channels. T-WorkFlow requires the radiator’s geometry files in .stp and .stl formats, along with additional user inputs provided through a graphical interface. For mesh generation, the software leverages the OpenFOAM tools blockMesh and snappyHexMesh. To ensure uniform mesh quality across different configurations, and thus, comparable numerical results, various pre-processing operations on the specific geometry files are needed. After generating the mesh, T-WorkFlow automatically defines a control surface for each radiator channel to monitor the volumetric flow rate distribution. This is achieved by combining the OpenFOAM command topoSet with specific geometric information directly obtained from the radiator’s CAD through FreeCAD. During the simulation, the software provides various outputs that automate the main post-processing operations, enabling quick and easy identification of the configuration that ensures the desired performance.

Mechanical behavior analysis of sandwich composite structures with different core geometries under three-point bending

This study presents a comprehensive investigation into the mechanical behavior of sandwich composite structures featuring six distinct core geometries under three-point bending conditions. Through detailed finite element analysis (FEA), the research examines the performance characteristics of I-shaped, traditional honeycomb (NIDA), O-shaped, X-shaped, semi-circular, and modified core geometries. The analysis focused on stress distribution patterns, displacement responses, and overall structural integrity. Results demonstrate that the semi-circular core geometry exhibits superior mechanical properties, achieving an 84.66% improvement in positive stress resistance and 74.79% enhancement in negative stress resistance compared to the traditional honeycomb reference model. The study revealed consistent linear elastic behavior across all models within the tested displacement range, with the semi-circular configuration showing optimal stress distribution and minimal core deformation. Using aluminum for facings and core materials, the research evaluated mechanical responses through displacement-controlled loading conditions, measuring stress concentrations at critical points and analyzing deformation patterns. This research provides valuable insights into the relationship between core geometry and mechanical performance, offering practical implications for engineering applications requiring high strength-to-weight ratios and enhanced flexural resistance in modern structural design.

Fiber morphological characteristics of bamboo Ferrocalamus strictus culms from different geographical distribution regions

The fiber index including fiber length, width, wall thickness and lumen diameter of Ferrocalamus strictus culms (1, 2, and ≥ 3 years) from Jinping, Mojiang and Lvchun counties of Yunnan Province was determined and the elemental content of the soil was also determined to analyze the fiber characteristics. The average relative fiber index measured for F. strictus culms were fiber length (1.30 mm), width (21.57 μm), slenderness ratio (60.79 μm), wall thickness (4.21 μm), lumen diameter (7.22 μm), and runkel ratio (1.22 μm), which belonged to the range of middle and long fibers. The fiber length increased with the culm age. The proportion of long fiber increased while short fibers decreased along with culm maturing. The fiber morphology did not show a specific trend with the culm height. Fiber length reached the maximum in the bottom portions of the culms. There is a correlation between fiber morphology and soil elements, the content of organic matter, total potassium, total sulfur, total aluminum, total zinc, total iron, total boron, alkali-hydrolyzed nitrogen and available silicon in the soil affects fiber morphology. The content of organic matter, total boron and alkali-hydrolyzed nitrogen in the soil from Mojiang County was largest. Comparatively, the culm fiber in Mojiang County had the best fiber index performance for utilization, since the greatest proportion of medium and long fibers and the optimal distribution of fiber length frequency was obtained from the culms in Mojiang County. This study can provide a theoretical basis for large-scale bamboo forest cultivation and the development and utilization of bamboo culm fiber.

Variation Characteristics of Actual Evapotranspiration and Uncertainty Analysis of Its Response to Local Climate Change in Arid Inland Region of China

Exploring the variation characteristics of actual evapotranspiration (ETa) and its response to climate change in the arid inland region of China is of great significance for strengthening regional water resources management and maintaining ecological environment security and stability. Taking the Dulan River Basin as the research area, based on the meteorological data from the Wulan Station and hydrological data from the Shanggaba Station from 1981 to 2020, the variation characteristics of ETa at the annual scale were analyzed. The ETa estimation model and joint distribution model of P and potential evapotranspiration (ET0) was constructed based on climate factors, and the uncertainty of ETa response to climate change was explored with the water balance method, multiple linear regression, marginal distribution function, Copula function, and Monte Carlo algorithm. The results showed that the multi-year mean value of ETa in the study area was 261.6 mm, and the interannual process showed an insignificant upward trend, and had no abrupt change during the period. There were two obvious main cycles, which were 19-year periodic changes on the 30-year time scale and 6-year periodic changes on the 9-year time scale. The ETa estimation model based on precipitation (P) and ET0 had good simulation accuracy. The optimal marginal distributions of P and ET0 were Pearson-III (P-III) distribution and Generalized Extreme Value (GEV) distribution, respectively. The Copula joint distribution probability density of P and ET0 was a symmetric saddle-shaped distribution. ETa showed an inverted ‘S’ distribution with the change in joint guarantee rate of P and ET0, ranging from 116.9 mm to 498.6 mm. ETa was an interval range under a certain joint guarantee rate. The research results can provide support for the assessment of ETa, and help to further understand the driving mechanism of climate change on ETa in the arid inland region of China.

Application of the Clark–Wright Method to Improve the Sustainability of the Logistic Chain

The incessant consumption of goods and materials underscores the need to address the growing problem of waste generation and its profound impact on environmental sustainability. The problem of waste removal can be approached in different ways, whether it is the routing of vehicles, the work of drivers, the optimal distribution of waste bins, or other matters in the entire waste process. The aim of this study is to investigate the possibilities of optimizing waste collection processes in the region using a slightly modified Clark–Wright method. Optimal waste collection routes are defined with a focus on cost reduction and overall optimization of logistic chain processes. The established mathematical model for the capacitated vehicle routing problem includes the principles of sustainability and environmental friendliness. The results indicate that the largest messenger of all the newly proposed routes are the routes containing the surrounding settlements. Newly designed routes lead to significant reductions in fuel consumption and vehicle maintenance, which has a positive impact on financial and environmental resources. The conclusion indicates that by applying the Clark–Wright method, we have achieved a reduction in the number of routes of twenty fewer routes. This study provides regions with a detailed plan to improve waste management practices, contributing to a future of increased sustainability and environmental awareness.

Subterranean termites (Coptotermes formosanus [Blattodea: Rhinotermitidae]) colonies can readily intercept commercial inground bait stations placed at label-prescribed distance

Abstract The Formosan subterranean termite, Coptotermes formosanus Shiraki, is both an economically impactful pest and a successful invader. One method of subterranean termite control is baiting. According to the label, baits are installed surrounding the structure at a uniform interval distance of ≈3 m. However, homeowners and pest control professionals are often concerned that termites may bypass bait stations and have access to the structure. To address this concern, we experimentally duplicated field conditions using a large planar arena (3.6 m × 1.1 m) to study the optimal distribution of bait stations based on colony-wide foraging activity. We installed 2 bait stations 3 m apart as per label instructions and introduced C. formosanus colonies to allow them to explore the arena by tunneling through the sand. In this real-scale arena, all termite colonies intercepted a bait station in an average of 21 (± 8 SD) days. We assumed that termites could find bait faster if there were more bait stations by overlaying additional hypothetical baits closer than per label instruction, but the improvement was incremental, requiring 4 times more stations (0.45 m interval) to obtain a significant difference. We also revealed the characteristic behavior after intercepting bait stations, termites created a burst of tunnels that radiated from the bait station. These branching tunnels averaged 16 cm in length, suggesting immediate interceptions of additional auxiliary stations placed within 16 cm of an active station. These findings contribute to our understanding on how subterranean termites intercept inground bait stations.

Manifold geometry optimization and flow distribution analysis in commercial-scale proton exchange membrane fuel cell stacks

The manifold structure in high-power Proton Exchange Membrane Fuel Cell (PEMFC) stacks critically influences airflow distribution, thereby affecting stack performance, temperature uniformity, and longevity. Therefore, this paper explores how manifold geometry affects fluid distribution within the manifold of a fuel cell stack. In addition, a new step-shaped manifold structure is established to improve the manifold flow field structure and enhance the uniformity of gas flow distribution in each single cell. In our study, each cell within the stack is modeled as a porous medium. We examine how varying the height at different positions within the manifold impacts the uniformity of gas flow distribution, focusing on different length ratios and heights. Our results demonstrate that adjusting the manifold shape improves airflow uniformity, with length ratios having a more pronounced impact than height variations. Specifically, the mass flow coefficient of variation decreased by 22.62 % and 23.07 % for cases 9 and 12, respectively. Similarly, the velocity inhomogeneity coefficient in the inlet manifold decreased by 21.22 % and 21.34 % for cases 9 and 12, respectively. Additionally, pressure distribution in case 9 showed greater uniformity. Our findings indicate that a manifold shape with a length ratio of 2/3 and a height of 2.5 mm delivers optimal performance.

Optimum fluoride distribution - and a free sample.

Optimum fluoride distribution - and a free sample.

Influence of Glass Granular Class on the Compressive Strength of Glass-Sand Mortar

This study examines the effect of glass particle size and color on the compressive strength of mortars made from glass, sand, and cement. A range of water-to-cement (W/C) ratios was applied, and tests were conducted to measure density and compressive strength at both 2 and 7 days. The glass, available in green, brown, and white, was introduced as both fine and coarse particles. The findings reveal that incorporating glass significantly enhances compressive strength compared to traditional mortars without glass, regardless of its color. Brown glass, especially in its coarse form, exhibited the best mechanical performance. With a W/C ratio of 0.48, mortars containing coarse brown glass particles reached a peak compressive strength of 34.78 MPa, showing a relative increase of 134.52% compared to mortars without glass. Fine brown glass particles also demonstrated strong compressive strength, though lower than the coarse ones. The density analysis showed a positive correlation between density and compressive strength, suggesting that denser mortars perform better mechanically. The superior performance of coarse glass particles is likely due to their optimal granular distribution, which enhances the bonding between cement and glass particles, leading to greater overall strength. Keywords: Compressive strength – Particle size – Recycled glass – Mortar – Density

Using kanban board for forming social time management skills of future IT specialists

For the professional development of students studying in information technology areas, it is important to develop social time management skills, i.e. skills in organizing well-coordinated teamwork and optimal distribution of responsibilities between team members with minimal time to achieve a common goal. The article aims to substantiate and elaborate methodological recommendations for developing social time management skills using kanban technology in organizing team activities of future IT specialists. Criteria for assessing the development of social time management skills are proposed. The article points out the necessity of including kanban project management technology not only as training content but also as a way to optimize time resources when performing team training projects.The article describes an experiment on teamwork organization of Nizhny Tagil State Socio-Pedagogical Institute (branch) of Russian State Vocational Pedagogical University students. At the initial stage, the determination of the level of formation of social time management skills among 2nd year students in the process of completing a project assignment on software product development was carried out within the discipline “High-level methods of informatics and programming” without the use of time management technologies. The results of this stage showed the need to develop time management skills of future IT specialists in the process of teamwork. Recommendations for organizing student teamwork when using project time management technologies using a kanban board were formulated, which will allow students to develop social time management skills.The next stage of the experiment was the organization of students’ teamwork using flexible project management methodology (kanban technology): taking into account the proposed recommendations in the experimental group, without the use of time management technologies in the control group. The results of the pedagogical experiment showed the expediency of following the proposed methodological recommendations.