Modular Building Research Articles

Prospective 3D Fat Navigator (FatNav) motion correction for 7T Terra MRI.

Ultra-high field (7T) MRI allows scans at sub-millimetre resolution with exquisite signal-to-noise ratio (SNR). As 7T MRI becomes more widely used clinically, the challenge of patient motion must be overcome. Retrospective motion correction is used successfully for some protocols, but for acquisitions such as slice-by-slice scans only prospective motion correction can deliver the full potential of 7T MRI. We report the first implementation of prospective 3D Fat Navigator ("FatNav") motion correction for the Siemens 7T Terra MRI. We implemented a modular Sequence Building Block for FatNav and embedded it into the vendor's gradient-recalled echo (GRE) sequence. We modified the reconstruction pipeline to reconstruct FatNav images online, coregistering them and sending motion updates to the host sequence online. We tested five registration algorithms for performance and accuracy on synthetic FatNav data. We implemented the best three of these in our sequence and tested them online. We acquired T1 and T2* weighted brain images of healthy volunteers correcting every other image for motion to visualise the effectiveness of online motion correction. Data were acquired with and without head immobilisation. We also tested performance while correcting every measurement for motion. Our implementation uses a 1.23 s 3D FatNav acquisition module and delivers motion updates in less than 3s, which is sufficient for motion updates every few k-space lines in typical scans. Corrected images are crisper with fewer visible motion artefacts. This improved sharpness is reflected quantitatively by an increase in the variance of the image Laplacian which is 1.59 x better for corrected vs uncorrected images. Profiles across the cerebral falx are 33% steeper for corrected vs uncorrected images. Prospective FatNav improves GRE image quality in the brain. Our modular Sequence Building Block provides a simple method to integrate motion correction in 7T MRI pulse sequences.

Improving the Energy Efficiency of the Modular Buildings Drying Room: A Case Study of Construction Site Cabins

Improving the Energy Efficiency of the Modular Buildings Drying Room: A Case Study of Construction Site Cabins

A shape grammar-based design for modular buildings based on the Vitruvian triad: The case of Mächtig Kiosk K67

The kiosk K67 is a known example of mass-produced modular architecture designed in the 60s. Although these modules allow many design solutions, the designer Saša Mächtig did not guide the generation of such designs so that the final composition of elements could fit a specific design purpose. This study has two aims. The first is the development of a shape grammar for the kiosk K67, which enables a deep analysis and synthesis of this paradigmatic design. The study’s second aim is to combine the kiosk K67 shape grammar with design principles to guide the generation of design solutions. To do so, the Vitruvian triad dimensions – firmitas, utilitas and venustas – are combined with the developed kiosk K67 shape grammar to generate design solutions based on specific design briefs. The study identifies how each dimension of the triad can impact architecture and then correlates these impacts with the kiosk K67 shape rules. Finally, shape grammar and design alternatives are presented. Each Vitruvian dimension is taken with different priorities in the design alternatives to test the concept. Such an approach enables us not just to analyse the design of Mächtig but also to use the developed shape grammar in a pedagogical way to explore how balancing design principles and constraints impact design outcomes.

A community effort to optimize sequence-based deep learning models of gene regulation.

A systematic evaluation of how model architectures and training strategies impact genomics model performance is needed. To address this gap, we held a DREAM Challenge where competitors trained models on a dataset of millions of random promoter DNA sequences and corresponding expression levels, experimentally determined in yeast. For a robust evaluation of the models, we designed a comprehensive suite of benchmarks encompassing various sequence types. All top-performing models used neural networks but diverged in architectures and training strategies. To dissect how architectural and training choices impact performance, we developed the Prix Fixe framework to divide models into modular building blocks. We tested all possible combinations for the top three models, further improving their performance. The DREAM Challenge models not only achieved state-of-the-art results on our comprehensive yeast dataset but also consistently surpassed existing benchmarks on Drosophila and human genomic datasets, demonstrating the progress that can be driven by gold-standard genomics datasets.

Reusable timber modular buildings, material circularity and automation: The role of inter-locking connections

As sustainability becomes a central concern in construction, the industry witnesses a significant surge in the adoption of material circularity principles, reflecting a new approach to resource management. Although mass timber construction holds significant potential for end-of-life (EoL) material circularity due to its natural materials and prefabrication, conventional connection systems hinder material reuse. Integrating interlocking techniques into modular construction could enhance circularity and enable future autonomous construction. This paper summarises design-for-reuse (DfR) strategies focusing on connection design for rapid assembly and disassembly of Cross-Laminated Timber (CLT) modules. These strategies can promote innovative connections with enhanced material circularity, which were illustrated through a recently proposed conceptual interlocking connections (MOD-IT). Additionally, a comparative cradle-to-cradle Life Cycle Assessment (LCA) evaluates the environmental impact and circularity potential of timber modular buildings using this connection system. The study underscores the pivotal role of strategic connection design in achieving a closed-loop system in timber construction. This advancement fosters sustainability by improving efficiency, adaptability, reusability, and autonomy in the construction process.

Random‐positioned‐sampling effect on probabilistic seismic demand modeling of modularized suspended buildings with free‐standing objects and architectural function regioning

AbstractThe definition of the targeted engineering demand parameters (EDPs) is important to probabilistic seismic demand modeling (PSDM), which produces probability density functions of EDPs conditioned on seismic intensity measure (IM). The targeted EDPs are usually defined at the group level to account for multiple components/units. Thus, they are affected by the considered range of units, i.e., the sample positions. For instance, the maximum peak floor acceleration (PFA) within the whole building differs from the maximum among only the important positions related to seismic loss. Additional uncertainties are induced in the PSDM of PFA if the sample positions vary when architectural function and non‐structural elements change. In this study, the aforementioned influence is termed random‐positioned‐sampling (RPS) effect, and it is investigated by targeting a modularized suspended building, which features the tuning mechanism, multiple major modes, uneven response envelopes, and notable non‐structural‐object‐structure interactions (NSOSI). Results show that the RPS effect lowers the maximum‐based group‐level EDP and increases the dispersion within the EDP sample sets, indicating that conventional PSDMs without considering the RPS effect are biased. The significance of the influence is positively correlated to the position‐wise coefficient of variation of EDP but negatively correlated to the density of sample positions. The combined influence of the NSOSI and the RPS effect is two‐sided for PSDM. The NSOSI amplifies the RPS effect via enlarging position‐wise dispersion of EDP, whereas, the RPS effect waives part of the detrimental scattered contributions from NSOSI. Overall, the IM performance is handicapped, even with IM optimization. However, it can be compensated if architectural function region information is acquired beforehand since the sample positions are restrained.

Experimental and theoretical study on axial compression behaviour of the modular combined column

Between the modular units of the modular steel building, there exists a combination of the adjacent modular columns. Due to the gaps between the modular columns and the lack of horizontal connections, the integrity of the modular steel structure is weak, which limits the use of modular steel structures in high-rise buildings. This paper proposes a kind of modular combined column realized the connection of modular single columns through the connectors and concrete, which can improve the integrity of the modular steel building. The assembly process of this new modular combined column is described. For axial compressive performance tests, four modular combined column specimens were designed, each with different height or different number of connecting plates. The axial compressive bearing capacity, ductility, stiffness, and other mechanical parameters of the specimens were analyzed according to the phenomena and load-displacement curves of the test. Then, the axial compression failure mode of the modular combined column specimens is compared and analyzed in conjunction with the finite element model. The results indicate that the axial compressive performance and ductility of the combined column suggested in this research are exceptional. The connector can enhance the overall mechanical qualities of the combined column by augmenting the restraining impact of concrete. Finally, the theoretical equation of the axial compression bearing capacity of the modular combined column is obtained by employing the superposition principle, and the equation's reliability is confirmed, along with the test results and the results of the numerical analysis.

Experimental study on the seismic performance of two-storey UHPC modular building structure

Ultra-high performance concrete modular building is a new structural system in which the module units made by the factory with UHPC materials are transported to the site for assembly. To study the seismic performance of UHPC module building structures, a two-story full-scale module building structure made by UHPC is designed in this study. Lateral cyclic loading tests are performed to investigate the seismic performance of the module building structures. The bearing capacity, failure mode, stiffness degradation, hysteretic performance, residual deformation, and strain skeleton curve are analyzed. Results indicate that the specimen undergoes three stress stages: elasticity, yield, and ultimate under lateral cyclic loading. At ultimate load capacity, the maximum inter-story drift ratio reached 1/57, and the load-bearing capacity was approximately 1.20 times the yield strength. The average ductility factor of the specimens was 3.42. The cracks mainly appear at the bottom and top of the walls of the module unit, and initial cracks occur at the top of the wall of the upper module unit. The specimen exhibits excellent seismic performance, full hysteretic curves, good dissipation capacity and ductility. The four corners between module units are connected by grouting sleeves in a reliable way to transfer force, which can ensure the overall deformation requirements of the structure.

Passive Ventilation of Residential Buildings Using the Trombe Wall

The article explores passive systems for regulating microclimates in residential settings, with a focus on modular constructions. It investigates the use of the trombe wall system for passive ventilation to ensure comfort and hygiene. The study examines building designs that enable effective air circulation without using mechanical systems. Furthermore, the effectiveness of the passive system of using solar energy with the trombe wall as a ventilation device in modular houses has been experimentally confirmed. Although the research confirms the effectiveness of this solar system in modular homes, there is limited documentation regarding its overall efficiency, particularly concerning the impact of the surface pressure coefficient on ventilation. The study establishes the correlations governing the thermosiphon collector’s effectiveness at varying air layer thicknesses. Optimal parameters, such as maximum air consumption (L = 120 m3h−1), are identified at an air layer thickness (δ) of 100 mm and outlet openings area (F) of 0.056 m2. These findings pave the way for improving passive systems aimed at maintaining optimal thermal and air conditions in modern homes. The findings suggest the potential for more efficient and sustainable housing solutions. Further research is essential to understand how factors like building design and wind speed affect ventilation system efficacy.

Axial and eccentric compressive behavior of partially encased channel–concrete composite columns with bolted connections in modular buildings

This paper introduces a novel partially encased channel–concrete composite (PECC) column for modular buildings, aiming to eliminate the need for cast-in-place concrete and facilitate rapid assembly. The PECC column consists of two prefabricated modules connected by high-strength bolts. To evaluate the column's viability, six slender specimens—one bare steel column and five composite columns—were tested under axial and eccentric compression. Variables considered included the presence of concrete, the type of transverse connections, bolt spacing, and load eccentricity ratio. The compression performance of the PECC columns was analyzed by examining their failure patterns, load–deformation responses, initial stiffness, compressive capacity, and ductility. Test results revealed that the PECC columns failed due to global buckling, concrete spalling, and crushing. The bolted connections effectively prevented module separation, enabling the PECC columns to exhibit favorable compressive behavior. The reinforced concrete encased in the channel delayed the column's buckling failure, increasing its initial stiffness and compressive capacity by 98% and 198%, respectively. Using perforated steel plates instead of transverse links between the concrete and the channel enhanced the column's initial stiffness by 20% but had little effect on its compressive capacity. Reducing the bolt spacing improved the column's initial stiffness and compression resistance by 50% and 5%, respectively. Additionally, a finite element model for the PECC columns was developed and validated against test results. Finally, simplified formulas derived from Eurocode 4 were proposed to estimate the resistance of PECC columns under axial and eccentric compression.

Research on Internal Flooding Analysis of Small Modular Reactors Based on Particle Method

Abstract The analysis of internal water flooding in nuclear power plants is a necessary part of safety review in the approval process of nuclear power plant construction projects. According to relevant regulations, it is necessary to conduct water flooding spread analysis on pipelines, water tanks, or pools filled with liquid in nuclear power plant buildings, analyze the spread path and water flooding height. This article analyzes and calculates the flow characteristics of water in a nuclear power plant building using a fluid calculation method based on the Lagrangian method (particle method). Taking the small modular reactor JR building as a case study, it analyzes the spread and height of four water flooding sources inside the building. According to the simulation time of 1800S, the results show that the flooding caused by the No. 2 water source is the most severe, with a flooding height of 1.367m. Drainage or preventive measures need to be taken to prevent the pipeline from breaking accidents; The flooding sources 1, 2, and 4 have a relatively mild impact, resulting in a lower flooding height and will not have a significant impact on important safety equipment, with little impact on the safety of nuclear power plants. The CFD analysis method was used to conduct water flooding analysis for nuclear power plants, which has the characteristics of strong adaptability and good visualization. It can dynamically simulate the entire process of water flooding analysis and better guide the design of water flooding protection for nuclear power plants.

Life cycle assessment of seismic resistant prefabricated modular buildings

Prefabricated Volumetric Modular Buildings (PVMB) have the potential to transform the construction industry and make a significant contribution to reaching sustainable development goals. Nevertheless, it is crucial to carefully evaluate the tangible benefits of implementing these systems, especially in buildings that require seismic calculations. This article compares three innovative PVMB structural systems, two reinforced concrete and one steel, with a conventional system, focusing on the economic and environmental aspects of a high seismic hazard zone. An end-to-end life cycle analysis was performed, and the results were used as quantitative criteria for a two-dimensional sustainability assessment. Five multi-criteria decision-making methods were used to identify the optimal alternative, resulting in a ranked list of solutions. The modular steel alternative is the most favorable option due to its balanced performance across all evaluation criteria despite being the most expensive. The conventional reinforced concrete alternative comes in second place, followed closely by the reinforced concrete modular alternative with dry connections. The modular reinforced concrete alternative with wet connections is the least favorable regarding environmental impact due to the extensive use of concrete and reinforcing steel. This study contributes significantly to sustainable construction research by establishing the tangible benefits of innovative systems compared to traditional methods. It offers specific insights into overcoming barriers to their more widespread adoption.

Optimal Location for Tower Crane and Dynamic Trailer Parking in High-Rise Modular Building Construction Project

Optimization of tower crane positioning is essential in precast building construction to ensure that a crane is in the right position to offer the best value for placing precast elements. The first goal is the optimization of transportation distances made by tower cranes, which will address the issues of efficiency and cost. This is done in a way that provides for minimization of the distances that lie between the trailer parking where elements are parked, the tower crane, and the construction installation point. However, current research fails to address the dynamic movement efficiency of trailers, especially when handling multiple trailers and several models of tower cranes, making this scenario an optimization problem that is classified as NP-hard due to the likelihood of causing a combinatorial explosion. This work endeavors to present a new mathematical model that has been applied to the Genetic Algorithm (GA). The ideal demand-generated model is designed to solve the optimal model and position of tower cranes and the prospective positioning of trailers for parking. The feasibility and applicability of the method exploited in the study are also established through a project case study. When adopting the proposed planning model compared to the earlier planning scale, comparisons highlight a small yet significant saving of 6% in time and cost when lifting elements instead of providing them from the trailers by setting up a new on-site stockyard. In addition, a great deal of enhancement is also observed in the final solution aspects, where the developed GA has even reduced the operational time and cost by half a percent each. The results of this research offer best-practice approaches to the position analysis of tower cranes in precast building construction to bring scalability and cost optimization to bear on the construction business.

Evaluating energy efficiency and environmental sustainability in fiberglass prefabricated modular structures

Fiberglass (FG) modular buildings are gaining increasing attention in the construction industry due to their adaptability, and potential for cost and time savings. This study compares the FG modular, house-like cubicles to concrete counter parts with respect to the environmental impacts and cost. The scope of the study encompasses the production and operational phase, especially air conditioning (AC) systems in hyper-arid climates. The effectiveness of insulation, quantified through R-value calculations, is evaluated across varying insulation thicknesses using Life Cycle Assessment (LCA). The results indicate that AC energy requirements significantly contribute to the climate change impact (CCH), accounting for 77 % and 90.5 %, in concrete and FG modules respectively. FG modules exhibit significantly higher environmental impacts compared to concrete modules in agricultural land occupation (+142.7 %), terrestrial ecotoxicity (+80.6 %), and urban land occupation (+66 %). Employing Net Present Value (NPV), the annual cost for FG and concrete modules was USD 963.9 and USD 550.8 per year, respectively. Sensitivity analysis indicates that increasing insulation (+5.00 cm) in FG modules reduces that annual cost due to cooling by 16.55 %, reduces CCH by 59.47 % but increases metal depletion by 130 %. This signifies the importance of incorporating the use phase when evaluating innovative building materials and methods.

Assessing operational resilience in food supply chains: a discrete-event simulation approach based on a framework for integrated decision-making

ABSTRACT Food supply chains (FSCs) play a critical role in ensuring food security but face increasing vulnerabilities to disruptions. With the objective to mitigate these challenges, this study focuses on assessing operational resilience within the Austrian dairy supply chain during sudden demand spikes. For this purpose, we introduce a novel framework for integrated decision-making which encompasses strategic, tactical, and operational perspectives, augmented with modular building blocks for FSC modelling and simulation. Based on this framework, we develop a discrete-event simulation model to assess and quantify the impact of strategic, tactical, and operational interventions on operational resilience. Our analysis reveals the effectiveness of upstream buffer stocks, adapted reordering strategies, and operational adjustments in response to demand increases. However, no single intervention consistently outperforms others across all performance metrics, emphasising the importance of tailored intervention selection. Hence, the major contributions, i.e. (1) the framework for integrated decision-making and (2) the quantification of potential interventions to enhance operational resilience, are useful for improving the operational resilience of FSCs and increase their ability to supply essentials in the short term despite disruptions. The results assist FSC actors in making more informed decisions to enhance operational resilience.

Extended end-of-life carbon assessment and savings: A case study of steel-framed modular buildings in Hong Kong

Modular construction (MC) advances conventional approaches such as material efficiency, shorter construction time, and reduced onsite waste, leading to lower carbon emissions in some stages. However, the End-of-Life (EoL) carbon has never been made explicit, particularly for MC, and there remains a lack of evidence on how much carbon emissions are generated and reduced from the EoL stage of modular buildings. To address the gaps, the present study proposes an EoL carbon estimation model for MC based on the life cycle assessment (LCA) method. The developed model was empirically validated through a case study of a typical high-rise steel-framed modular residential building in Hong Kong. The results reveal that net carbon emissions during the EoL stage could be −764.40 kg CO2 eq./m2, presenting the great carbon savings potential of MC. Compared to those in traditional on-site construction areas, steel modular components have far greater capabilities to mitigate carbon emissions, as most of them can be reused. Nevertheless, an average of 41.56 kg CO2 eq./m2 of carbon is still released in the EoL stage, most of which is contributed by transportation, followed by waste disposal, demolition, and waste processing. This study makes an original contribution to understanding the extent of EoL carbon emissions and the potential of carbon savings in steel modular buildings. Also, these findings unveil the practical significance of reusing modules for EoL carbon mitigation and provide useful suggestions for demolition contractors and policymakers to mitigate carbon emissions to further promote the transition towards carbon neutrality.

Therapeutic applications of RNA nanostructures.

RNA-based therapeutics have gained wide public interest in recent years. RNA is a versatile molecule that exists in many forms including mRNA, siRNA, miRNA, ribozymes, and other non-coding RNAs and is primarily applied for gene therapy. RNA is also used as a modular building block to construct RNA nanostructures. The programmable nature of RNA nanostructures enables the generation of simple, modulable, and multi-functional RNA-based therapeutics. Although the therapeutic application of RNA may be limited due to its structural instability, advances in RNA nanotechnology have improved the stability of RNA nanostructures for greater application. Various strategies have been developed to enhance the stability of RNA nanostructures enabling their application in vivo. In this review, we examine the therapeutic applications of RNA nanostructures. Non-immunogenic RNA nanostructures can be rationally designed with functional RNA molecules to modulate gene expression for gene therapy. On the other hand, nucleic acids can be sensed by cellular receptors to elicit an innate immune response, for which certain DNA and RNA motifs can function as adjuvants. Taking advantage of this adjuvant potential, RNA nanostructures can be used for immunotherapy and be designed for cancer vaccines. Thus, we examine the therapeutic application of immunogenic RNA nanostructures for cancer immunotherapy. RNA nanostructures represent promising platforms to design new nanodrugs, gene therapeutics, immunotherapeutic adjuvants, and cancer vaccines. Ongoing research in the field of RNA nanotechnology will continue to empower the development of RNA nanostructure-based therapeutics with high efficacy and limited toxicity.

Geopolymer-based insulated wall incorporating construction and demolition waste: Experimental assessment of thermo-physical behavior

The benefit of the application of geopolymers in the building sector is nowadays undisputed. In addition to good structural characteristics, these are characterized by interesting thermophysical properties, obtained through a production process, that reduces CO2 emissions and could incorporate recycled material, thus responding to environmental sustainability. However, it is noted the lack of studies regarding the in-field thermal performance. Thus, the aim of the present study is to investigate the thermal performance, under real conditions, of an innovative geopolymer-based insulated wall. It incorporates over 70% of net weight of Construction and Demolition Waste materials. The wall is conceived within the European project called “Green INSTRUCT” aimed to realize modular prefabricated building elements, for retrofitting and new construction of buildings. Two wall prototypes are analysed, which differ for the type of lightweight aggregate of geopolymer matrix, 3% by weight: expanded polystyrene or extruded polystyrene. The study refers to almost one year of continuous monitoring within a full-scale test room located in southern Italy. The method developed consists of 5 different phases and it involves also a normative-insulated reference wall. The results show higher insulation level of the proposed wall package, with a reduction of the heat flux of about 66% and more stable indoor thermal conditions, compared to the reference wall. Also the inertial properties are satisfactory, showing an experimental decrement factor equal to 0.05 and a time-shift of decrement factor higher than 6 h. All told, the experimental results can provide valuable insights into the real impact of innovative technology on energy efficiency and indoor thermal comfort.

Damage mitigation strategies for progressive collapse of modular steel buildings following sudden corner module removal

AbstractThis study evaluates gravity‐induced progressive collapse performance and damage mitigation strategies in modular steel buildings (MSBs) A typical three‐dimensional six‐story structure was modeled and analyzed using the finite element method, focusing on the instantaneous removal of a corner module. The study includes a parametric evaluation of the influence of beam moment capacity on progressive collapse and investigates the effect of using concrete as an infill for square hollow section columns. Additionally, the effectiveness of short K‐shaped braces in limiting gravity‐induced collapse was assessed. A response/damage index (DI) was proposed to quantify the overall structural response. The findings indicate that semirigid beam‐column connections outperform fully rigid connections. Both concrete‐filled columns and K‐shaped braces mitigate structural damage, with K‐shaped braces proving more effective in preventing collapse. Although increasing the beam moment‐resisting capacity reduced the DI, improvements were marginal beyond 50% of the fully rigid connection capacity. Higher beam moment capacities reduced local vertical displacement at the corner joint but led to undesirable lateral deformations. Reducing beam rigidity/capacity by 25% mitigated global structural deformations. The optimal beam moment capacity was identified as 75% of the total section capacity when using concrete‐filled columns. K‐shaped braces applied at the column midpoint entirely prevented progressive gravity‐induced collapse and no lateral deformations were observed in braced structures with fully rigid beam‐column connections, unlike unbraced structures. Concrete‐filled columns offer a cost‐effective solution for preliminary production of MSBs, while K‐shaped braces are suitable for retrofitting existing buildings. Further research is necessary to address other parameters influencing the mitigation of progressive collapse in MSBs.

Seismic Performance of Fully Modular High-Rise Buildings with Superelastic Tendon Restrained Rocking

Seismic Performance of Fully Modular High-Rise Buildings with Superelastic Tendon Restrained Rocking