Design Considerations Research Articles

Assessing Turbulence Model Performance in OpenFOAM for Natural Convection Simulations

Abstract Natural convection processes are pivotal in various engineering applications, necessitating accurate and reliable computational fluid dynamics (CFD) models for their simulation. This study evaluates the efficacy of different turbulence models implemented in OpenFOAM for a natural convection scenario, aiming to identify the most suitable model for capturing complex thermal and fluid dynamic behaviors. We compared several turbulence models, including the k − ε, k − ω, and k − ω SST, using a benchmark thermal convection case. Our methodology involved setting up the simulations to reflect realistic thermal gradients and boundary conditions, followed by a rigorous analysis of temperature distribution, vertical velocity profiles, and computational efficiency. The results indicate that the k − ω SST achieved the lowest averaged root mean square error (RMSE) values for temperature (0.076) and vertical velocity (0.03) while also requiring the fewest convergence iterations (314) compared to k − ε (411) and k − ω (1474). These findings demonstrate that the k − ω SST model is a suitable compromise between accuracy and computational cost for engineering applications. This study underscores the importance of selecting an appropriate turbulence model in OpenFOAM to enhance the accuracy of natural convection simulations, which can significantly influence design and safety considerations in engineering systems.

Usability, Engagement, and Report Usefulness of Chatbot-Based Family Health History Data Collection: Mixed Methods Analysis.

Family health history (FHx) is an important predictor of a person's genetic risk but is not collected by many adults in the United States. This study aims to test and compare the usability, engagement, and report usefulness of 2 web-based methods to collect FHx. This mixed methods study compared FHx data collection using a flow-based chatbot (KIT; the curious interactive test) and a form-based method. KIT's design was optimized to reduce user burden. We recruited and randomized individuals from 2 crowdsourced platforms to 1 of the 2 FHx methods. All participants were asked to complete a questionnaire to assess the method's usability, the usefulness of a report summarizing their experience, user-desired chatbot enhancements, and general user experience. Engagement was studied using log data collected by the methods. We used qualitative findings from analyzing free-text comments to supplement the primary quantitative results. Participants randomized to KIT reported higher usability than those randomized to the form, with a mean System Usability Scale score of 80.2 versus 61.9 (P<.001), respectively. The engagement analysis reflected design differences in the onboarding process. KIT users spent less time entering FHx information and reported more conditions than form users (mean 5.90 vs 7.97 min; P=.04; and mean 7.8 vs 10.1 conditions; P=.04). Both KIT and form users somewhat agreed that the report was useful (Likert scale ratings of 4.08 and 4.29, respectively). Among desired enhancements, personalization was the highest-rated feature (188/205, 91.7% rated medium- to high-priority). Qualitative analyses revealed positive and negative characteristics of both KIT and the form-based method. Among respondents randomized to KIT, most indicated it was easy to use and navigate and that they could respond to and understand user prompts. Negative comments addressed KIT's personality, conversational pace, and ability to manage errors. For KIT and form respondents, qualitative results revealed common themes, including a desire for more information about conditions and a mutual appreciation for the multiple-choice button response format. Respondents also said they wanted to report health information beyond KIT's prompts (eg, personal health history) and for KIT to provide more personalized responses. We showed that KIT provided a usable way to collect FHx. We also identified design considerations to improve chatbot-based FHx data collection: First, the final report summarizing the FHx collection experience should be enhanced to provide more value for patients. Second, the onboarding chatbot prompt may impact data quality and should be carefully considered. Finally, we highlighted several areas that could be improved by moving from a flow-based chatbot to a large language model implementation strategy.

Motion Artifacts in Dynamic EEG Recordings: Experimental Observations, Electrical Modelling, and Design Considerations

Despite the progress in the development of innovative EEG acquisition systems, their use in dynamic applications is still limited by motion artifacts compromising the interpretation of the collected signals. Therefore, extensive research on the genesis of motion artifacts in EEG recordings is still needed to optimize existing technologies, shedding light on possible solutions to overcome the current limitations. We identified three potential sources of motion artifacts occurring at three different levels of a traditional biopotential acquisition chain: the skin-electrode interface, the connecting cables between the detection and the acquisition systems, and the electrode-amplifier system. The identified sources of motion artifacts were modelled starting from experimental observations carried out on EEG signals. Consequently, we designed customized EEG electrode systems aiming at experimentally disentangling the possible causes of motion artifacts. Both analytical and experimental observations indicated two main residual sites responsible for motion artifacts: the connecting cables between the electrodes and the amplifier and the sudden changes in electrode-skin impedance due to electrode movements. We concluded that further advancements in EEG technology should focus on the transduction stage of the biopotentials amplification chain, such as the electrode technology and its interfacing with the acquisition system.

Enhancing Hematopoietic Stem Cell Transplantation Success: The Crucial Role of Architectural Design in Transplant Units and Hematology Departments

Aim: This paper aims to explore the critical role of architectural design in Hematopoietic Stem Cell Transplantation (HSCT) procedures, focusing on how various aspects of design influence patient outcomes, staff efficiency, infection control, and overall safety. The study seeks to understand how the physical environment impacts both the immediate and long-term recovery of patients undergoing HSCT and to advocate for design principles that enhance patient and caregiver experiences. Discussion: Hematopoietic Stem Cell Transplantation (HSCT) has emerged as a vital therapeutic modality for a diverse spectrum of hematological disorders and malignancies. As medical and technological advancements continue to evolve, the significance of the physical environment in which HSCT procedures are conducted becomes increasingly evident. This paper delves into how architectural design affects patient well-being, staff efficiency, and infection control, emphasizing the importance of creating environments that support psychological well-being. It examines the impact of design on infection prevention, safety during emergencies, and the overall efficiency of healthcare delivery. The discussion also highlights the role of sustainability and green design principles in minimizing the environmental footprint while promoting patient recovery. Conclusions: The paper concludes that architectural design plays a transformative role in enhancing patient experiences and healthcare outcomes in HSCT settings. It underscores the need for a patient-centric approach to design that integrates wellness-focused elements and advanced technology. The study advocates for a collaborative effort among healthcare institutions, architects, designers, and policymakers to create supportive, efficient, and sustainable healthcare environments. By prioritizing these design considerations, healthcare environments can significantly improve the HSCT journey and contribute to the broader realm of healthcare excellence.

Design and construction of the cylindrical drift chamber for the COMET Phase-I experiment

COMET is an experiment at J-PARC that searches for the charged lepton flavor violating process of neutrino-less muon-to-electron conversion (μ→e conversion) in a muonic atom. The COMET Phase-I experiment, which represents the first stage of its staged approach, utilizes the cylindrical drift chamber (CDC) as the main detector to measure the momentum of electrons emitted from μ→e conversion in a 1 T magnetic field. The CDC is designed for optimal performance to achieve the best momentum resolution and effectively separate the μ→e conversion electron signal from background signals. This design entails adapting He:i-C4H10 (90:10) as its chamber gas and employing an all-stereo wire configuration. This document provides a comprehensive overview of the CDC detector, encompassing design considerations, mechanical structure, construction methodologies, and results of performance evaluations conducted using cosmic-rays.

Quarry rock reef design features influence fish assemblage structure across a systematically heterogenous restoration reef

To restore an area of temperate rocky-reef degraded by sedimentation, scour, and burial, a large quarry rock reef, the Palos Verdes Restoration Reef (PVR), was built with a heterogenous design including high relief elements intended to increase fish biomass productivity and support a diverse reef community. The replicated design features provide a unique opportunity to study the effects of reef design on fish habitat use patterns. To determine how submodule scale habitat features are associated with variation in the assemblage structure of eleven focal fish species on the PVR we conducted diver-operated stereo-video surveys on all 18 PVR modules 9–13 months after construction. The highest mean densities of most focal fish species and highest total fish densities were observed on high and medium-relief reef submodules and their adjacent ecotones positioned on the offshore sides or ends of modules. These included the most abundant species on the PVR, the zooplanktivorous Blacksmith (Chromis punctipinnis), as well as the fishery species Kelp Bass (Paralabrax clathratus) and California Sheephead (Bodianus pulcher). On the inshore side of parallel modules, the reef and ecotone transects on low and medium relief submodules exhibited the lowest total mean fish densities, and consistently lower mean focal fish species densities. Focal fish species assemblages also differed between the reef and sand-rock ecotone transects. Reef-resident planktivorous fishes likely contribute to reef primary and secondary productivity through consumer mediated nutrient transport and are an important consideration in restoration reef design. Future reef restoration designs should consider incorporating replicated heterogeneous design features including the placement of higher relief elements relative to shore and current patterns as a special consideration for providing habitat for planktivorous reef-resident fishes.

STRUCTURAL DESIGN AND ANALYSIS OF A 20-STORY MIXED-USE HIGH-RISE RESIDENTIAL AND COMMERCIAL BUILDING IN DHAKA: SEISMIC AND WIND LOAD CONSIDERATIONS

This study, conducted in the Department of Civil Engineering at Stamford University Bangladesh, focuses on the structural design and analysis of a 20-story mixed-use high-rise building in Dhaka, accommodating both residential and commercial functions. The objective of the study is to gain insights into the design and analysis of an intermediate moment-resisting frame that addresses the specific challenges posed by seismic and wind loads in a dense urban environment. A commercial building, defined as a structure primarily dedicated to business activities, requires specialized design considerations that extend beyond residential construction, including the need for larger beams, increased floor space, and accommodation for various commercial functions. In high-density urban areas, like Dhaka, the design of multi-story commercial buildings, such as shopping malls and office complexes, presents additional challenges related to space constraints, vertical shopping preferences, and the high cost of land. The study emphasizes the importance of creating a structural design that balances rentable space, aesthetics, cost, safety, and comfort, while addressing the lateral forces caused by wind and seismic activity. This analysis aims to assist engineers and architects in meeting the growing demand for multifunctional high-rise structures, ensuring both safety and functionality in the face of complex environmental and structural factors.

Artificial Intelligence-Powered Technologies For Independent Living Among Older Adults: A Review

Abstract Background The ageing populations in Ireland and around the world has led to an increased focus on technologies that support independent living for older adults. Artificial intelligence (AI) has emerged as a promising solution, with various AI-powered technologies being proposed to assist their daily lives. This review aims to synthesize the findings of studies exploring AI-powered technologies for independent living among older adults. Methods A systematic literature search was conducted using relevant databases, including PubMed, IEEE Xplore, and Google Scholar. The search terms included “artificial intelligence” and “independent living”. Studies published between 2009 and 2023 that investigated AI-powered technologies for independent living among older adults were included in the analysis. Results The included studies investigated various AI-powered technologies including tablets, wearable devices like smartwatches, web portals for carers, Internet of Things (IoT) solutions, user-centered design considerations, the integration of AI with sociology and healthcare, smart home technology, and ambient information systems. The pooled results indicated that AI-powered technologies can improve independent living outcomes for older adults. Benefits included real-time monitoring and health deterioration recognition, fall detection, personalised care, cognitive assistance and reduced isolation. User-centered design approaches and the integration of AI with sociology and healthcare were also found to be essential factors in the successful implementation of these technologies. Conclusion This analysis provides evidence supporting the effectiveness of AI-powered technologies in promoting independent living among older adults. IoT solutions and smart home technology appear to be particularly promising. However, the successful implementation of these technologies requires a multidisciplinary approach, incorporating user-centered design and the integration of AI with sociology and healthcare. Further research is needed to explore the long-term impact of AI-powered technologies on the well-being and autonomy of older adults.

Banked Primary Progenitor Cells for Allogeneic Intervertebral Disc (IVD) Therapy: Preclinical Qualification and Functional Optimization within a Cell Spheroid Formulation Process.

Background/Objectives: Biological products are emerging as therapeutic management options for intervertebral disc (IVD) degenerative affections and lower back pain. Autologous and allogeneic cell therapy protocols have been clinically implemented for IVD repair. Therein, several manufacturing process design considerations were shown to significantly influence clinical outcomes. The primary objective of this study was to preclinically qualify (chondrogenic potential, safety, resistance to hypoxic and inflammatory stimuli) cryopreserved primary progenitor cells (clinical grade FE002-Disc cells) as a potential cell source in IVD repair/regeneration. The secondary objective of this study was to assess the cell source's delivery potential as cell spheroids (optimization of culture conditions, potential storage solutions). Methods/Results: Safety (soft agar transformation, β-galactosidase, telomerase activity) and functionality-related assays (hypoxic and inflammatory challenge) confirmed that the investigated cellular active substance was highly sustainable in defined cell banking workflows, despite possessing a finite in vitro lifespan. Functionality-related assays confirmed that the retained manufacturing process yielded strong collagen II and glycosaminoglycan (GAG) synthesis in the spheroids in 3-week chondrogenic induction. Then, the impacts of various process parameters (induction medium composition, hypoxic incubation, terminal spheroid lyophilization) were studied to gain insights on their criticality. Finally, an optimal set of technical specifications (use of 10 nM dexamethasone for chondrogenic induction, 2% O2 incubation of spheroids) was set forth, based on specific fine tuning of finished product critical functional attributes. Conclusions: Generally, this study qualified the considered FE002-Disc progenitor cell source for further preclinical investigation based on safety, quality, and functionality datasets. The novelty and significance of this study resided in the establishment of defined processes for preparing fresh, off-the-freezer, or off-the-shelf IVD spheroids using a preclinically qualified allogeneic human cell source. Overall, this study underscored the importance of using robust product components and optimal manufacturing process variants for maximization of finished cell-based formulation quality attributes.

Design considerations and preliminary hydrodynamic analysis of an offshore decentralised floating wind-hydrogen system

Despite the number of works on the techno-economics of offshore green hydrogen production, there is a lack of research on the design of floating platforms to concomitantly support hydrogen production facilities and wind power generation equipment. Indeed, previous studies on offshore decentralised configuration for hydrogen production, implicitly assume that a floating platform designed for wind power generation (FOWT) can be also suitable as a floating wind hydrogen system (FWHS). This work proposes a novel design for an offshore decentralised FWHS, and analyses the effects of the integration of the hydrogen facilities on the platform's dynamics and how this in turn affects the performances of the wind turbine and the hydrogen equipment. Our findings indicate that despite the reduction in platform's stability, the performance of the wind turbine is barely affected. Regarding the hydrogen system, our results aim at contributing to further assessment and design of this equipment for offshore conditions.

Simulation-Based Hybrid Energy Storage Composite-Target Planning with Power Quality Improvements for Integrated Energy Systems in Large-Building Microgrids

In this paper, we present an optimization planning method for enhancing power quality in integrated energy systems in large-building microgrids by adjusting the sizing and deployment of hybrid energy storage systems. These integrated energy systems incorporate wind and solar power, natural gas supply, and interactions with electric vehicles and the main power grid. In the optimization planning method developed, the objectives of cost-effective and low-carbon operation, the lifecycle cost of hybrid energy storage, power quality improvements, and renewable energy utilization are targeted and coordinated by using utility fusion theory. Our planning method addresses multiple energy forms—cooling, heating, electricity, natural gas, and renewable energies—which are integrated through a combined cooling, heating, and power system and a natural gas turbine. The hybrid energy storage system incorporates batteries and compressed-air energy storage systems to handle fast and slow variations in power demand, respectively. A sensitivity matrix between the output power of the energy sources and the voltage is modeled by using the power flow method in DistFlow, reflecting the improvements in power quality and the respective constraints. The method proposed is validated by simulating various typical scenarios on the modified IEEE 13-node distribution network topology. The novelty of this paper lies in its focus on the application of integrated energy systems within large buildings and its approach to hybrid energy storage system planning in multiple dimensions, including making co-location and capacity sizing decisions. Other innovative aspects include the coordination of hybrid energy storage combinations, simultaneous siting and sizing decisions, lifecycle cost calculations, and optimization for power quality enhancement. As part of these design considerations, microgrid-related technologies are integrated with cutting-edge nearly zero-energy building designs, representing a pioneering attempt within this field. Our results indicate that this multi-objective, multi-dimensional, utility fusion-based optimization method for hybrid energy storage significantly enhances the economic efficiency and quality of the operation of integrated energy systems in large-building microgrids in building-level energy distribution planning.

Fast machine-learning-enabled size reduction of microwave components using response features

Achieving compact size has emerged as a key consideration in modern microwave design. While structural miniaturization can be accomplished through judicious circuit architecture selection, precise parameter tuning is equally vital to minimize physical dimensions while meeting stringent performance requirements for electrical characteristics. Due to the intricate nature of compact structures, global optimization is recommended, yet hindered by the excessive expenses associated with system evaluation, typically conducted through electromagnetic (EM) simulation. This challenge is further compounded by the fact that size reduction is a constrained problem entailing expensive constraints. This paper introduces an innovative method for cost-effective explicit miniaturization of microwave components on a global scale. Our approach leverages response feature technology, formulating the optimization problem based on a set of characteristic points derived from EM-analyzed responses, combined with an implicit constraint handling approach. Both elements facilitate handling size reduction by transforming it into an unconstrained problem and regularizing the objective function. The core search engine employs a machine-learning framework with kriging-based surrogates refined using the predicted improvement in the objective function as the infill criterion. Our algorithm is demonstrated using two miniaturized couplers and is shown superior over several benchmark routines, encompassing both conventional (gradient-based) and population-based procedures, alongside a machine learning technique. The primary strengths of the proposed framework lie in its reliability, computational efficiency (with a typical optimization cost ranging from 100 to 150 EM circuit analyses), and straightforward setup.

A Systematic Literature Review of Design Considerations, Challenges and Guidelines in Primary School Physical Learning Space Design

A Systematic Literature Review of Design Considerations, Challenges and Guidelines in Primary School Physical Learning Space Design

Exploring the Manifestation of Design for Manufacturing Heuristics in Students' Early-Stage Engineering Design Concepts

Abstract Additive manufacturing (AM) can produce designs in a manner that greatly differs from the methods used in the older, more familiar technologies of traditional manufacturing (TM). Despite this method of manufacturing designs that were seemingly inconceivable in the past, designers often forgo the new design considerations of AM and instead rely on their familiarity with the design considerations more commonly associated with TM, regardless of the manufacturing process they intend to use. This can lead to unnecessary material usage, increased manufacturing time, and can result in designs which are poorly manufactured. To remedy this problem, there is a need to intervene early in the design process to help address any concerns regarding the use of AM design heuristics. This work aims to address this opportunity through a preliminary exploration of the design heuristics that students naturally leverage when creating designs in the context of TM and AM. With the common design heuristics that students are most likely to use in their designs identified, future studies will cement early-stage design support tools that emphasize the significant heuristics found herein. For example, this work found that the design heuristic “incorporating complexity” was the most significant indicator of designs most suited for AM and should therefore be highly encouraged/emphasized when guiding designers in the use of AM. In doing so, it will be possible for early-stage design support tools to maximally improve designs that are intended to be manufactured for AM.

A Platform for Connectivity and Synergy between Parents and Teachers of Children with Autism

Collaboration between parents and teachers of Children with Autism (CWA) is emphasized for effective education while the communication gap between both sides impedes it. The lack of specially designed tools to supplement the collaboration process in low-resource settings led us to initiate the research to design a platform for facilitating the synergy between both parties. This qualitative research was conducted in two phases where Phase I interviewed n=10 participants (parent=5, teacher=5). They emphasized personalized communication, maintaining privacy and accountability, and school authority’s role in ensuring meaningful communication ideating three design guidelines. The prototype was developed accordingly and evaluated in Phase II with n=18 (parent=8, teacher=10) participants. They shared different use cases of the application, suggested modifications, and recommended new features. The work presents the parents and teachers of CWA with a platform to connect and synchronize their efforts and provides the HCI researchers contextual design considerations while designing for resource-constrained communities in Global South.

Agent-based Mediation on Smartphone Usage among Co-located Couples

Smartphone overuse around family and friends has been shown to be increasing over the past years and often leads to limited one-to-one interaction between co-located individuals. Smartphone-based virtual agents have been shown to be effective for behavior intervention and mediation, such as promoting physical activity. Little is known about leveraging smartphone-based agents to play a role in communication and facilitate conversation between co-located individuals. In this paper, we explore strengthening conversations between co-located couples by introducing a smartphone-based agent that acts as a conversation facilitator between them. We contrast the results with a text-based alternative. Our findings suggest that virtual agents serve as a valuable social entity mediating support in couples' communication and relationship dynamics. Through this, we suggest design considerations for this context that leverage the unique qualities of virtual agents.

Prediction and design of transcriptional repressor domains with large-scale mutational scans and deep learning.

Regulatory proteins have evolved diverse repressor domains (RDs) to enable precise context-specific repression of transcription. However, our understanding of how sequence variation impacts the functional activity of RDs is limited. To address this gap, we generated a high-throughput mutational scanning dataset measuring the repressor activity of 115,000 variant sequences spanning more than 50 RDs in human cells. We identified thousands of clinical variants with loss or gain of repressor function, including TWIST1 HLH variants associated with Saethre-Chotzen syndrome and MECP2 domain variants associated with Rett syndrome. We also leveraged these data to annotate short linear interacting motifs (SLiMs) that are critical for repression in disordered RDs. Then, we designed a deep learning model called TENet ( T ranscriptional E ffector Net work) that integrates sequence, structure and biochemical representations of sequence variants to accurately predict repressor activity. We systematically tested generalization within and across domains with varying homology using the mutational scanning dataset. Finally, we employed TENet within a directed evolution sequence editing framework to tune the activity of both structured and disordered RDs and experimentally test thousands of designs. Our work highlights critical considerations for future dataset design and model training strategies to improve functional variant prioritization and precision design of synthetic regulatory proteins.

Enhancing safety in narrow-band transformerless PLC couplers with a passive symmetrical filter

As the demand for efficient data transmission over existing power infrastructure grows, power-line communication (PLC) systems have become increasingly vital. However, integrating communication signals with high-voltage power lines poses significant safety challenges, emphasizing the need for reliable, safe, and high-performance components. To address cost and safety concerns, this article introduces a symmetrical third-order band-pass filter design that employs a transformerless coupler, avoiding the expense and bulk of traditional transformers while enhancing both equipment and human safety in narrow-band PLC systems. The design, functionality, and safety considerations are discussed, with a focus on implementing a passive analog Butterworth filter, chosen for its flat frequency response in the passband. Additionally, we address the safety aspects of transformerless couplers in PLC applications, emphasizing their reliability and efficiency in maintaining signal integrity while minimizing the risks associated with high-voltage environments. Simulations validated the proposed design, confirming its effectiveness in achieving the desired frequency response. The design is cost-effective due to the elimination of the transformer and ensures safety through the strategic rearrangement of the coupler components, which isolates the power line from the communication side.

Telerobotic Intergroup Contact: Acceptance and Preferences in Israel and Palestine.

We explore telerobotics as a novel form of intergroup communication. In this form, remotely operated robots facilitate embodied and situated intergroup contact between groups in conflict over long distances, potentially reducing prejudice and promoting positive social change. Based on previous conceptual frameworks and design hypotheses, we conducted a survey on the acceptance and preferences of the telerobotic medium in Israel and Palestine. We analyzed the responses using a mixed-method approach. The results shed light on differences in attitudes between the groups and design considerations for telerobots when used for intergroup contact. This study serves as a foundation for the implementation of a novel method of technology-enhanced conflict resolution in the field.

A Flyback Converter with a Simple Passive Circuit for Improving Power Efficiency

This paper proposes an effective method to improve the power efficiency of the flyback converter in the continuous conduction mode (CCM). The proposed converter uses a simple passive circuit to reduce the switching power losses. The current through the output diode can be shifted to a new branch where one diode, one inductor, and one auxiliary winding of the transformer are included. The output diode current can be reduced to zero for the zero-current switching of the output diode. The additional inductor is used to control the changing rate of the additional diode current to reduce the reverse-recovery current. Keeping the simplicity of the passive method, the proposed converter improves the power efficiency compared to the conventional converter. The circuit configuration and the operation principle are described. The design considerations are presented, including the simulation verification. The experimental results for a 45 W prototype are discussed to evaluate the performance of the proposed converter. The proposed converter has achieved a power efficiency of 93.5% for the rated load condition, improving the power efficiency. The applications of the proposed converter are also discussed for the future research directions.