Block Layout Research Articles

Block Layout Optimization Using the Harmony Search and Particle Swarm Algorithms

Block Layout Optimization Using the Harmony Search and Particle Swarm Algorithms

Investigation on Hydraulic Fracturing and Flexible Anti-Hydrofracturing Solution for Xiaowan Arch Dam

Understanding hydraulic fracturing in concrete super-high arch dams is vital for the implementation of safety measures on the bearing surface. In this study, we conducted tests on hydraulic fracturing for the Xiaowan arch dam (294.5 m) to analyze concrete behavior at cracks under various stress conditions. The risk of hydraulic fracturing near the dam heel was identified without compressive stress. Addressing this, we propose a flexible anti-hydrofracturing system using GB sealing material and a spray polyurea coating. Simulation tests on three schemes: ‘3 mm GB plate + 4 mm polyurea’, ‘1 mm GB glue + 5 mm polyurea’, and ‘7 mm polyurea’ showed effective prevention of hydrofracturing at concrete crack openings of 5 mm, 8 mm, or 10 mm under 300 m water pressure. Field tests supported ‘3 mm GB plate + 4 mm polyurea’ and ‘7 mm polyurea’ as optimal solutions for dam sections. Implementation involves a protective block layout with ‘3 mm GB plate + 4 mm polyurea’ on blocks and ‘7 mm polyurea’ in interval zones and corners. Since 2008, maximum leakage, including rock foundation, has remained minimal at 2.78 L/s under regular water levels. These insights aid similar concrete dams in optimizing safety systems.

A multi-objective optimization framework for designing urban block forms considering daylight, energy consumption, and photovoltaic energy potential

Urban form significantly influences building energy consumption. However, most research has primarily focused on quantifying the relationship between the two factors, with limited exploration of optimizing urban form to enhance building energy performance. Moreover, studies often fail to consider multiple performance objectives simultaneously. This study proposes a multi-objective optimization framework for early urban design stage to improve energy and environmental performance in residential block layouts. The performance objectives include energy consumption, photovoltaic energy potential, and sunlight hours. The framework is implemented using the parametric platform Rhino & Grasshopper, where a parametric model controls the layout of blocks. Ladybug Tools plugin is employed for performance simulation, and Wallacei is used for optimization. An ideal residential block in Jianhu City, China, is taken as a case study. The study generates a total of 1896 valid solutions, including 58 Pareto solutions. The performance of the Pareto solutions demonstrates considerable improvements, indicating the effectiveness of optimizing urban form for enhancing energy and environmental performance. Compared to the initial solution, a typical Pareto solution showcases a 1.5% reduction in energy consumption, a 52.7% increase in photovoltaic energy potential, and a 50% increase in sunlight hours. These findings underscore the pivotal role of urban block morphology in influencing energy consumption, photovoltaic potential, and daylighting. The proposed multi-objective framework in this study enhances and facilitates sustainable block form design, which is expected to provide technical support for energy-efficient or low-carbon urban design.

Optimizing block morphology for reducing traffic pollutant concentration in adjacent external spaces of street canyons: A machine learning approach

Residential blocks located in near-road environments are exposed to traffic-related air pollution that adversely affects the health of residents. Pedestrian height areas in adjacent external spaces (AES) of street canyons are most severely affected by traffic pollutants. In order to find block morphological optimization strategies that can mitigate the concentration of pollutants in the area, machine learning (ML) regression models were investigated to replace the time-intensive computer fluid dynamic (CFD) model. Data from 1000 CFD simulation cases were used to train and test the ML models. The best surrogate model was selected and coupled with optimization algorithms. Both single-objective and multi-objective optimization problems based on regional concentration parameters were discussed. The results showed that the block's standard deviation of building height (BHstd) was an essential morphological parameter that can effectively impact the pollutant concentration. The effect mechanism of the building height at different locations in the block on the concentration of the pollutant in the different regions also varies. The optimum block configuration obtained from the optimizations coupled ML model can facilitate reducing pollutant concentrations. This study provides a framework for residential block design optimization that can help urban designers efficiently evaluate and select block layouts conducive to reducing the impact of traffic pollutants.

Solar tower CSP plants with transcritical cycles based on CO2 mixtures: A sensitivity on storage and power block layouts

In this work three CO2-based binary mixtures, CO2 + C6F6, CO2 + C2H3N and CO2 + C4F8, are compared as innovative working fluids for closed power cycles in CSP plants. Adopted in transcritical cycles, they lead to cycle efficiencies higher than sCO2 cycles at minimum temperatures above 50 °C, a typical condition for arid regions with high solar radiation. The analysis considers four plant configurations: the first with direct storage, solar salts as HTF and cycle maximum temperatures of 550 °C, while the three other plants adopt sodium as HTF and an indirect storage system, designed for cycle maximum temperatures of 550 °C, 625 °C and 700 °C. Detailed models are used to characterize the solar fields optical performance, the receiver thermal efficiency and the HTF pump consumption, both at design and off-design conditions, for large scale plants located in Las Vegas. Different power block layouts are considered, spanning from the more efficient ones to cycles with a high heat recovery capacity. In addition, the impact of the mixtures on the design of heat exchangers is evidenced, with convincing results with respect to the heat transfer characteristics of CO2. Considering the resulting yearly performances and LCOE of each configuration, the adoption of indirect storage systems is considered a viable solution for high temperature solar plants. The three innovative mixtures allow for a reduction in LCOE with respect to sCO2 cycles (up to 10 $/MWh, depending on the configuration), capacity factors above 70% for the specific location, optimal solar multiples around 2.8 and 12 equivalent hours of TES.

Optimization of holes routing in hydraulic manifold blocks based on simulated annealing algorithm

The design of the hydraulic manifold block is time-consuming, laborious, and prone to make mistakes due to the vertical intersection and dense complexity of its internal oil passage network. The mathematical optimization model of this problem is given based on the comprehensive analysis of the structural characteristics and design rules of the internal orifices of the hydraulic manifold block. Using the integrated circuit layout algorithm for reference, an optimization design method of a multi-wire mesh channel network based on routing sequence optimization is proposed and verified by an example. The research results show that the optimization of the connection order between multiple wire networks at both ends and the routing order between multiple wire networks in a single-wire network can not only achieve the optimal design of the connectivity of the single-wire network but also ensure the optimal connectivity result of the entire hole network. At the same time, as the bottom core algorithm of the integrated block layout optimization design, it can provide a powerful technical guarantee for improving the integrated block design level, quality, and automation.

A sequential space syntax approach for healthcare facility layout design

This paper presents a two-phase approach for solving the facility layout problem in a physical rehabilitation hospital. The first phase solves the block layout problem, where the relative location and size of the departments in the facility are determined. The model used in this phase is based on Space Syntax which offers a series of tools that can be used to analyze and quantify spatial relations that are useful when modeling block layouts. Two Space Syntax-based metrics are introduced to model proximity and ease of access in layout designs, critical qualities in health care settings. A tabu search algorithm based on a novel nested-bay encoding is used to find the block layouts. A set of test cases from a large provider of rehabilitation hospitals shows the ability of this approach to handle healthcare-specific design requirements. An important concern for physical rehabilitation hospitals, where a large portion of the patient population is especially vulnerable to infectious diseases, and which has gained greater attention due to the COVID pandemic, is infection control. The approach herein is more capable of addressing control of infectious disease than existing metrics by providing designers with more granular control of space separation. Results show that the Space Syntax approach provides powerful, but easy to use, modeling capabilities, and that the resulting block layouts are more realistic. The second phase model is a mixed integer program for constructing corridor networks on a block layout that minimize travel distance, number of intersections, and maximum traffic on a turn. Both models are configurable so that facility designers can generate different designs according to their goals by changing the model parameters.

A bottom-up multi-objective optimisation approach to dynamic facility layout planning

Dynamic facility layout planning (DFLP) involves determining an appropriate arrangement scheme of the elements making up the production system for each time period into which the planning horizon is divided. When formulating the problem as an optimisation model, using the traditional top-down approach is usual, which firstly determines the block layout (BL) and then the detailed layout (DL) of each work cell. However by this approach, the BL generates area constraints in the detailed phase, which sometimes limit its implementation. In this context, the present paper presents a multi-objective mixed integer non-linear programming (MOMINLP) model that allows the problem to be addressed by considering an alternative approach, known in the literature as the bottom-up approach. The proposed model, called bottom-up mDFLP, considers three objective functions: (1) minimise the total material handling cost (TMHC) and the total rearrangement cost (TRAC); (2) maximise the total closeness rating (TCR) between departments; (3) maximise the area utilisation ratio (AUR). The original MOMINLP is transformed into a more computationally efficient multi-objective mixed integer linear programming (MOMILP) model. The proposed model is applied and validated in a case study of a company in the metal-mechanic sector with 12 departments for three 4-month periods.

Layout Redesign to Eliminate Stagnation Using Blocplan to Increase Production Efficiency

The rapid growth of the automotive industry was also followed by growth in subsidiary companies. One of the subsidiary companies is a company that produces auto parts such as wheels. Sales volume in 2021 increased to more than 2 million products while for 2022 to April it was more than 1 million products. High demand is not accommodated due to inadequate production capacity, one of which is the machining area. This study aims to increase efficiency by redesigning the layout of the factory which is considered to increase production results in the machining area. The method used in this research is Block Layout Overview with Computerized Planning using Logic and Algorithm (Blocplan). The results showed that the redesign of the machining area could reduce stagnation by adding 1 unit of multi drill machine. Relayout in the machining area can reduce 93” time stagnation for the K2SA rear ABS type which can produce 2 outputs at once. The delay in the machining area can be reduced from 4,863 seconds to 0 seconds.

ANALYSIS OF NEW TECHNICAL SOLUTIONS FOR THE RITM-200 REACTOR PLANT IN THE PROJECT 22220 OF UNIVERSAL NUCLEAR ICEBREAKERS

The project 22220 of a new two-stage universal nuclear icebreaker involves the construction of 5 similar icebreakers to work in the Arctic. At the same time, two icebreakers of this project are already in operation. RITM-200 reactor installations are installed on icebreakers. The main feature of these reactor installations (RI) is the monoblock layout of the main equipment. This type of layout should gradually replace existing since 1975 and a positively proven block layout of the reactor installation. To date, the development of new reactor installations is small and it is too early to talk about the practical results of their operation, but it is possible to discuss new technical solutions in the project. At the same time, there is a long experience in the operation of previous projects of nuclear icebreakers (10520, 10521, 10580) with a total operating time of about 400 reactor years. The received comprehensive information on the creation and operation of these facilities is a solid basis for comparing the technical solutions used on new universal nuclear icebreakers, including on the reactor installations. A methodology for comparing already known technical solutions for existing installations with new ones proposed by the designer is proposed in the paper. In this situation, the author acts as an independent expert with an assessment of the relative positivity of new technical solutions. At the same time, the assessment is carried out according to 6 comparison criteria developed on the basis of the analysis of the accompanying technical documentation on reactor installation developed by the Afrikantov OKBM. Six most important new integrated technical solutions for the modernization of the reactor installation for universal nuclear icebreakers are considered. Such an analysis is also important because an optimized power unit for low-power floating nuclear power plants is being developed on the basis of the design experience gained. As an energy source, two RHYTHM-200M steering wheels are used here. In addition, the RITM-400 reactor plant with a thermal capacity of 315 MW for the leader icebreaker with a capacity of 120 MW is conceptually similar to the RITM-200 and the differences are mainly due to increased thermal power and an increased number of energy loops while maintaining dimensions. The analysis has showed that the complexes of technical solutions mainly have a high relative positivity and take into account the latest scientific achievements and technology development.

Monitoring Ambient Parameters in the IoT Precision Agriculture Scenario: An Approach to Sensor Selection and Hydroponic Saffron Cultivation.

The world population is on the rise, which demands higher food production. The reduction in the amount of land under cultivation due to urbanization makes this more challenging. The solution to this problem lies in the artificial cultivation of crops. IoT and sensors play an important role in optimizing the artificial cultivation of crops. The selection of sensors is important in order to ensure a better quality and yield in an automated artificial environment. There are many challenges involved in selecting sensors due to the highly competitive market. This paper provides a novel approach to sensor selection for saffron cultivation in an IoT-based environment. The crop used in this study is saffron due to the reason that much less research has been conducted on its hydroponic cultivation using sensors and its huge economic impact. A detailed hardware-based framework, the growth cycle of the crop, along with all the sensors, and the block layout used for saffron cultivation in a hydroponic medium are provided. The important parameters for a hydroponic medium, such as the concentration of nutrients and flow rate required, are discussed in detail. This paper is the first of its kind to explain the sensor configurations, performance metrics, and sensor-based saffron cultivation model. The paper discusses different metrics related to the selection, use and role of sensors in different IoT-based saffron cultivation practices. A smart hydroponic setup for saffron cultivation is proposed. The results of the model are evaluated using the AquaCrop simulator. The simulator is used to evaluate the value of performance metrics such as the yield, harvest index, water productivity, and biomass. The values obtained provide better results as compared to natural cultivation.

Перспективы применения и отработка технологии беспроводной передачи электрической энергии между космическими аппаратами

The purpose of the study was to examine the state and possible fields of short-and-long term application of technology for spacecraft-to-spacecraft wireless transmission of electrical energy. The paper focuses on a space experiment on the transmission of electrical energy from the Russian Segment of the International Space Station to the Progress transport cargo ship in the laser channel and introduces an experiment scheme that provides the required duration of sessions, a given distance of energy transmission, as well as the fulfillment of the safety requirements for the station crew. The paper describes the scientific equipment “Pelican”, developed for the space experiment, specifies its features, gives its main characteristics and layout of blocks, and shows the ways to improve the equipment’s performance to ensure wireless transmission of energy in space.

Flexural behavior of hollow interlocking compressed stabilized earth-block masonry walls under out-of-plane loading

The present study aims to investigate the out-of-plane flexural behavior of hollow interlocking compressed stabilized earth block (ICSEB) masonry walls reinforced with bamboo and steel bars. The effect of grouting, channel block and reinforcement layout (vertical and mesh type) was assessed. A total of thirty masonry walls were fabricated using fibre reinforced blocks and categorized into five groups: two groups of ungrouted and grouted (without bamboo or steel reinforcement) masonry wall specimens and three groups of grouted masonry wall specimens reinforced with bamboo splints and steel bars. All the specimens were subjected to a constant pre-compression load while lateral load parallel to bed joints was gradually applied until failure. In addition, the experimental moment capacity of reinforced masonry walls was compared with the MSJC-11 formulations to assess the applicability. A statistical regression analysis was then performed on the test results to predict the ultimate moment and deformation capacity of all wall specimens. Test results suggest that grout alone has significantly contributed to the load carrying capacity of wall specimens but with a marginal improvement in deformability. While, channel blocks has no significant effect on load carrying capacity of reinforced grouted masonry wall specimens. Bamboo splints and steel bars as internal reinforcements are very effective in preventing the sudden failure and also enhancing the flexural resistance of masonry walls. Steel mesh showed the highest load carrying capacity, lateral deformation and energy absorption capacity. The addition of bamboo or steel reinforcement combined with grout improved the ultimate load carrying, deformation capacity and energy absorption of walls by 114.88%–260.55%, 19%–35.52% and 168.25%–489.28% respectively.The MSJC-11 code overestimated the moment capacity of reinforced masonry walls; whereas the regression models developed accurately predicted the moment capacity and lateral deformation of the masonry walls.

An extensible multi-block layout warehouse routing optimization model

As a special Traveling Salesman Problem, the order picking problem is theoretically challenging and practically significant. Therefore, it has received the attention of many scholars for many years. Compared with a single block layout with parallel picking aisles, the optimal solution for a multi-block layout is much more difficult to find due to the increase in cross-aisles. In this paper, two mathematical optimization formulations are proposed to deal with the multi-block layout problem. One takes the picking position as a unit, and the other takes the picking aisle as a unit. Since picking aisles are connected to each other through specific cross aisles, different picking configurations, access modes, and constraints are introduced. The distance between picking positions is divided into horizontal distance and vertical distance, forming different parts in the objective function. On this basis, two mathematical planning models for the single picker routing problem are constructed. The scale and solution time of the two models are independent of the number of cross aisles, so they have good overall performance when compared with other optimization algorithms through numerical experiments. These models can be expanded to include important features of modern inventory systems, such as scattered storage.

Measuring the effect of track count and wire segment length on the layout area of switch blocks for tile-based FPGAs

Switch block flexibility is an important design metric in FPGA architectural research. A switch block with high flexibility can provide better routability for implementing digital applications, which can lead to better performance and logic density. Flexibility, however, does come at the cost of an increase in the layout area of switch blocks, which can lower performance and logic density. Consequently, it is important to accurately estimate the layout area of increasing switch block flexibility in order to better design FPGA architectures. This work focuses on the popular disjoint switch block design and evaluates the accuracy of the traditional active-based area estimation models based on realistic layouts. We found that the current active-based area models are inaccurate in estimating the true area cost of increasing switch block flexibility. This inaccuracy is due to the inability of the current models to consider the full effect of routing track count and wire segment length, two important flexibility parameters, on the layout area of switch blocks. We found that by including wiring area into the estimation of FPGA switch block layout area, one can significantly improve the accuracy of predicting the true area cost of these flexibility parameters. These results allow FPGA architects to better optimize future FPGA designs for routability and consequently for performance and logic density.

Effect of mooring mode and internal mass block layout on eccentric rotating wave energy converter model

Reliability and energy conversion ability are the most concerned performance indexes of Wave Energy Converter Eccentric Rotating Wave Energy Converter (ERWEC) with closed shell can protect energy conversion unit away from seawater, which has shown excellent reliability. However, energy conversion ability of Eccentric Rotating Wave Energy Converter is poor and the method to improve performance of ERWEC is still not clear. The objective of this work is to improve mooring security, motion attitude stability and energy conversion ability of ERWEC. In this paper, experimental model of ERWEC was developed, and energy conversion mechanism was clarified. Experiments on various mooring modes and various internal mass block layouts were carried out. Besides, breaking coefficient, instability coefficient and energy conversion coefficient were calculated to evaluate performance of ERWEC. The result showed that the effect of mooring mode on mooring security, motion attitude stability and energy conversion ability was coupled to the effect of internal mass block layout on those three indexes. Furthermore, under determined mooring mode condition, internal mass block layout was optimized by multi-objective genetic algorithm. This paper provides basis for conceptual design of mooring mode and real-time control of mass block layout to achieve better mooring security, motion attitude stability and energy conversion ability of ERWEC.

The cooling effect of high geothermal tunnel construction environment: A case of ice and spray method in an extra-long tunnel

With the tunnel construction is moving towards the direction of “deep, large and long”, high geothermal and its heat damage occurs frequently, and pure mechanical ventilation cannot meet the temperature requirements of the tunnel construction environment. In this paper, through on-site monitoring and numerical simulation methods, we conducted an in-depth study on ice block cooling and spray cooling auxiliary methods, revealing their effects on the tunnel temperature and comparing the impact of key parameters such as different shapes and layout of ice blocks, different flow rates and temperatures of spray and different positions of nozzles on the cooling effect. Results show that the fresh airflow will be heated by the surrounding rock, resulting in the worse cooling effect of the tunnel section the further away from the working face. Compared with pure mechanical ventilation, ice blocks, and spray cooling methods cooled the tunnel by 0.5–2.5 °C and 2–5 °C respectively. For the ice block cooling method, the flaky shape and double-sided arrangement is the fastest cooling design scheme, and the further away from the working face, the faster the cooling speed increases. The role played by the ice blocks is mainly to cool the fresh airflow heated by the surrounding rock and maintain its temperature. For spray cooling method, the tunnel environment can be controlled in the ideal condition by setting the nozzle flow rate and droplet temperature to 0.02 kg/s and 20 °C under the conditions of the tunnel cross-section of about 28 m2, fresh airflow of 25 °C, and return airflow velocity of about 2.1 m/s.

Steiner TSP based on aisle as a unit for order picking

The picker routing problem (PRP) is one of the most crucial problems in warehouse management. It is also defined as the Steiner Traveling Salesman Problem (Steiner TSP). We deal with the Steiner TSP for a low-level picker-to-parts order picking system within a multi-block warehouse, which is much more complicated to be solved compared with those in a single block layout. After a series of preprocessing, such as reducing the vertices, transforming picking aisles and limiting the connections between vertices, we construct a Steiner graph with flexible nodes based on aisle as a unit. Different picking access modes as well as restrictions on connections for picking aisles are introduced. Then, a mixed integer linear programming model for Steiner TSP based on aisle as a unit is presented. We compare the numerical computation on the benchmarks in exiting literatures. Our Steiner graph can greatly reduce the scale of vertices and arcs without losing characteristics of the original problem. And the model has good overall performance, especially in large scale cases.

A mixed-integer linear programming formulation for the modular layout of three-dimensional connected systems

Given the considerable complexity of process plants, there has been a great deal of research focused on aiding the design of plant layout through mathematical optimisation, i.e. optimising the positioning of the equipment in the plant for space and cost efficiency. Recently, the use of modular approaches within the construction industry, whereby work is performed off-site before being assembled on-site, has become a popular and powerful way of reducing build schedules and costs. Modular approaches have many other real applications where items must be packed to minimise the connections between them (e.g. piping, wiring, modular office and factory layouts) and consider the modular layout of the system.In this paper, we provide a formulation of the problem that, in addition to the standard layout problem, considers a modular block layout to allow modular construction and transportation of the plant. The problem is represented as a directed network, with the aim to pack the items into predefined containers and minimise the rectilinear distance between the connected items. We propose mixed-integer linear programming (MILP) models for the 2-dimensional and 3-dimensional problems and solve them using the state-of-the-art mathematical programming solver, Gurobi. Because of the combinatorial nature of the problem, solutions involving a large number of items may not converge and a suboptimal solution must be considered. However, our results suggest that even in the case of optimising a large number of items, the suboptimal solutions found after a reasonable number of iterations where deemed, by a domain expert, to be a good enough starting point to continue the design process, especially in the early concept phase.

Investigation of optimal natural ventilation in residential complexes design for temperate and humid climates

Renewable energies have been discussed as the main efficient solution for solving many issues regarding climate change. Statistics said that the share of the building sector is very high in excessive use of fossil fuels. This study aimed to utilize the natural wind to create optimal natural ventilation to achieve thermal comfort of the indoor environment through the best layout and placement of residential blocks, creating proper distance between blocks and orienting blocks properly inside a residential complex site in a summery humid climate. Also, some strategies for achieving indoor thermal comfort are proposed based on the climatic need calendar of hot and humid Anzali port. The study of wind flow across blocks and within buildings was performed by the computational fluid dynamics (CFD) simulation method. Results showed that the proper orientation for the blocks was provided by rotation of +20° till +30° to the southeast, which would receive the prevailing summer wind from the northeast and lead it into the interior environment and when the distance between blocks is equal to the height (h) of buildings (±%25 h) can create the maximum wind velocity. Also, to reach this high wind velocity in the buildings the size of outlet openings should be larger than the inlet openings.