Iterative Design Methodology Research Articles

Managing the heat: In-Vessel Components.

The Spherical Tokamak for Energy Production (STEP) programme aims to deliver a first-of-a-kind fusion prototype powerplant (SPP). The SPP plasma places extreme heat, particle and structural loads onto the plasma-facing components (PFCs) of the divertor, limiters and inboard and outboard sections of the first wall. The PFCs must manage the heat and particle loads and wider powerplant requirements relating to safety, net power generation, tritium breeding and plant availability. To enable STEP PFC concepts to be identified that satisfy these wide-ranging requirements, an iterative design ('Decide & Iterate') methodology has been used to synchronize a prioritized set of decisions, within the fast-paced, iterative, whole plant concept design schedule. This paper details the 'Decide and Iterate' methodology and explains how it has enabled the identification of the SPP PFC concepts. These include innovative PFC solutions such as a helium-cooled discrete and panel limiter design to increase tritium breeding while providing sufficient coverage and enabling individual limiter replacement; the integration of the outboard first wall with the breeding zone to enhance fuel self-sufficiency and power generation; and the use of heavy water (D2O) within the inboard first wall and divertor PFCs to increase tritium breeding within the outboard breeding zone. This article is part of the theme issue 'Delivering Fusion Energy - The Spherical Tokamak for Energy Production (STEP)'.

Extending higher education recognition programs through a dedicated post-award reflective practice tool

ABSTRACT Higher education professional recognition programs, which lead to the awarding of such accolades as teaching and learning fellowships, offer participants opportunities to reflect carefully on their practice. However, few resources exist to help participants engage in reflection after the award-receiving stage. This reflection is important in helping participants not rest on their laurels and, instead, build on the practices for which they received recognition. Through a process of collaborative reflection, a group of fellowship-recipients, from different disciplines and higher education institutions, addressed this gap as stakeholder-participant-researchers by developing a transdisciplinary approach to undertaking post-award reflective practice. From this collaboration, a novel two-stage tool was developed using an iterative design methodology. The tool presented in this paper as the result of this research can be understood as a means of supporting self-paced, continued post-award reflective practice; the tool’s first stage guides users through retrospective reflection, looking back on previous achievements, while the second stage leads users through anticipatory planning, looking towards the future, to achieve fresh goals. The tool thus deepens the reflective practice of recognition program awardees and supports their ongoing professional development. This paper reports on the development of this bespoke tool, which may be enacted in varied settings.

Development of a New and Mechanically Intelligent Anti-Tremor Utensil

People living with Parkinson’s disease or with essential tremors face many obstacles in their everyday lives. Being able to eat independently is one of them. Many technologies already exist to help people who have difficulty eating independently. However, following a review of existing devices with a team of occupational therapists, it was found that many commercially available solutions were either unhelpful or too expensive. The need for better adapted solutions was obvious so an iterative design methodology based on the user's needs was followed to create a new anti-tremor utensil. The starting point of the design was to analyze the existing utensils to understand better the pros and cons of the available solutions. During the iterative design methodology, several prototypes emerged and led to the creation of the final spoon prototype presented in this paper. A total of 5 different adaptative spoons were designed and are presented in this paper. A sensor-based frequential analysis combined with an occupational therapist review indicates that the proposed prototype is effective against certain types of tremors and that it could potentially help people living with tremor while they eat. The next step of the development will be to test the new prototype with potential users.

Bayesian cell therapy process optimization.

Optimizing complex bioprocesses poses a significant challenge in several fields, particularly in cell therapy manufacturing. The development of customized, closed, and automated processes is crucial for their industrial translation and for addressing large patient populations at a sustainable price. Limited understanding of the underlying biological mechanisms, coupled with highly resource-intensive experimentation, are two contributing factors that make the development of these next-generation processes challenging. Bayesian optimization (BO) is an iterative experimental design methodology that addresses these challenges, but has not been extensively tested in situations that require parallel experimentation with significant experimental variability. In this study, we present an evaluation of noisy, parallel BO for increasing noise levels and parallel batch sizes on two in silico bioprocesses, and compare it to the industry state-of-the-art. As an in vitro showcase, we apply the method to the optimization of a monocyte purification unit operation. The in silico results show that BO significantly outperforms the state-of-the-art, requiring approximately 50% fewer experiments on average. This study highlights the potential of noisy, parallel BO as valuable tool for cell therapy process development and optimization.

Developing and Validating Critical-Heutagogy Learning (CHL) to Enhance Lifelong Learning: A Rasch Analysis Approach

This research is dedicated to the development and validation of Critical-Heutagogy Learning (CHL), an innovative pedagogical approach designed to foster lifelong learning among university students. In an era characterized by rapid changes, the imperative for lifelong learning is paramount, necessitating individuals to continually update their knowledge and skills to remain adaptable and successful in diverse environments. To evaluate the validity and reliability of CHL, this study employs Rasch analysis. The development phase of CHL encompassed an exhaustive review of relevant literature, consultations with subject matter experts, and an iterative design methodology. This process was critical to ensure that CHL adhered to established principles of lifelong learning while promoting critical thinking and heutagogical practices. For the validation phase, CHL tools were administered to a heterogeneous group of students across multiple educational contexts. The gathered data underwent rigorous Rasch analysis to ascertain the framework's reliability, evaluate item fit, and pinpoint areas necessitating enhancements. The findings indicate that CHL is both a valid and reliable approach, with a high percentage (89.5%) of student respondents affirming its effectiveness in fostering engagement in learning and enhancing autonomous learning competencies. Additionally, this study delves into the interactions between bias and differential item functioning. The outcomes of this research offer a valuable contribution to the field of education, presenting a rigorously validated framework that supports lifelong learning. This is achieved through the promotion of critical thinking and the facilitation of independent learning skills, thus aligning with contemporary educational objectives and needs.

Rapid and sustained contact tracing training for COVID-19 in San Francisco: a training model for developing an emergency public health workforce.

The City and County of San Francisco was the first municipality in the United States to institute a COVID-19 contact tracing program. The San Francisco Department of Public Health (SFDPH) and the University of California, San Francisco (UCSF) created an outcome-based fully remote contact tracing curriculum using participatory learning methods to train non-public health emergency workers as contact tracers. Between April and December 2020, we trained over 300 individuals in contact tracing skills and procedures over three training phases. Using iterative curriculum design and Kirkpatrick's evaluation methodology, we aimed to ensure high quality and successful person-centered contact tracing. The resulting curriculum consisted of 24 learning outcomes taught with six participatory skills development activities, asynchronous materials, and one-on-one contact tracer support. We collected more than 700 responses from trainees using various evaluation tools across the training phases, and contact tracers interviewed more than 24,000 contacts after training in our program. Our evaluations showed that knowledge and skills improved for most trainees and demonstrated the utility of the training program in preparing trainees to perform person-centered contact tracing in San Francisco. Local health jurisdictions and state health agencies can use this model of curriculum development and evaluation to rapidly train a non-public health workforce to respond to future public health emergencies.

Supporting Physical Activity in Later Life: Perspectives From Older Adults

The older population, especially those living alone, is less likely to meet recommended physical activity levels than other age groups and deserves more attention in this era of population ageing. However, existing technologies for supporting physical activity have been generally poorly aligned with the needs of older adults. Reasons for such problem are manifold, including the lack of involving older adults in design and evaluation, prevalent technology-driven perspectives, and the complexity of designing behavior change technology. Therefore, this research project aims to investigate how to better design behavior change technology to support the needs of older adults living alone for physical activity, which will address four main aspects: meeting user needs, investigating the rationale of technology design, improving co-design practice, and evaluating designed technology. To this end, this project will employ a human-centered iterative design methodology and actively involve the target group in the design process to let their voices heard and incorporated in design. This research will not only contribute to a deeper understanding towards the needs and preferences of this insufficiently studied group, but also identify implications for improving co-design practices as well as design opportunities for future behavior change technology.

Integrated thermal modeling, analysis, and sequential design of heat exchanger surfaces of a natural circulation RDF boiler including evaporator tubes

Although the design methodology of individual heat transfer surfaces in a natural circulation boiler such as evaporator tubes, convective and radiative superheaters are available in the literature, the multiple feasible design solutions of boiler heat exchanger surfaces coupled with drift flux based model of evaporator tube and cost-based optimal solution of the surfaces is not common. The present study proposes a sequential iterative design methodology for all heat transfer surfaces (from the evaporator to air preheater) in a single boiler to bridge the gap between industrial needs and academia. The salient temperature points in different locations are used in the design, alternate solutions are considered, and the overall cost is minimized. The evaporator tubes are designed based on a two-phase flow drift flux model and fixed volume constraint. The radiant and radiative-convective superheaters are modeled using weighted average flue gas temperature. The models of evaporator section and other heat exchangers are validated extensively with data of natural circulation loop and components integrated into real plants, respectively. The feasible and optimal design solutions of all heat transfer surfaces are proposed for a medium-scale (35 MW) Refused-Derived Fuel-fired Boiler (RDFB). The variation of mass flux through the evaporator tubes with the fuel feed rate is observed to be gravity-driven initially followed by friction-dominated. It is observed that for lowering the exit flue gas temperature of 14.93% below 150 °C, the required area of air preheater is 21.83% higher, while for a reduction of temperature of 21.42%, the area increment is 55.8%, which increases the investment cost rapidly. Results also indicate that the radiative heat exchangers require less heat transfer surface for a higher pitch to diameter ratio while the opposite characteristic is observed for the convective heat exchangers.

An iterative hydraulic design methodology based on numerical modeling for piano key weirs

Piano Key Weir (PKW) is a special type of overflow weir which provides an improved discharge capacity with its increased crest length. Increased discharge capacity makes this weir an attractive alternative in the rehabilitation of existing spillways. After the introduction of this new weir type, many experimental and numerical studies are conducted to understand the effect of the numerous geometrical parameters on the discharge capacity. However, empirical discharge formulas suggested by different researchers are not conforming to a unique expression mostly due to dependence on the experimental conditions from which they are derived. A numerical approach is used in the present study to investigate the dependence of discharge capacity of a PKW unit on several geometric parameters. Numerical models are developed and three-dimensional velocity fields are computed using FLOW-3D® software. Discharge efficiency of a PKW over an equivalent linear sharp-crested weir is evaluated within the practical range of parameters from 145 numerical solutions for 29 different PKW models. Numerically obtained data is used to form dimensionless expressions for the weir height and length as function of discharge efficiency which are proposed to facilitate an iterative numerical solution to meet the design requirements of a given project. This approach allows cost optimization while dimensioning the PKW for the required hydraulic capacity. The design procedure based on iterative numerical solutions is described and exemplified.

Stiffening near-net-shape functional parts of Inconel 718 LPBF considering material anisotropy and subsequent machining issues

Additive manufacturing of metallic parts has witnessed significant development. The laser powder bed fusion (LPBF) process has emerged as a key process for manufacturing thin-walled components. However, despite the significant advances, post-machining operations are required for the improvement of dimensional and surface quality, specifically in low stiffness components. This study proposed an iterative design methodology for improving the stiffness of such LPBF components. In the first stage, an initial assessment of the machining conditions was performed to obtain a first approach to the relationship between tooth passing, natural, and chatter frequencies. Thereafter, a method to improve Young's modulus was proposed by evaluating the elastic anisotropy of different manufacturing configurations. Furthermore, LPBF lateral stiffeners were included in the workpiece design, thereby converting the final workpiece into a temporary assembly. The proposed methodology was applied in a case study for finishing thin-walled bent ducts and a comparison for surface quality between stiffened and non-stiffened ducts using the proposed methodology was conducted. A significant roughness and cutting force reduction (≈50%) were obtained for the stiffened duct.

Design Methodology of a Three Coil IPT System With Parameters Identification for EVs

The benefits of intermediate couplers (IC) in inductive power transfer (IPT) systems are well documented in the literature. However, the lack of guideline rules makes the selection process of the passive components and operation mode difficult. This paper presents an iterative design methodology based on the equivalent mathematical model of the system to determine the optimal magnetic coupler (MC) dimensions and resonant tanks parameters that operates the system in a quasi constant current mode. It was found that the transconductance function of a series-series (SS) with an intermediate coupler exhibits a quasi-load independent characteristic when the reflected reactance from the receiver side is null. The design methodology then combines the self and mutual coupling profiles of the MC, obtained from a finite element analysis (FEA) tool, with the system specifications and constraints to find all possible solutions. A set of selection metrics are proposed to identify the optimal solution. This work also presents an identification method of the load and mutual inductances based only in the information available from the transmitter side. The proposed method uses the steady-state equations and does not require any form of communication to the receiver side. An experimental prototype was built and assembled in a converted combustion vehicle with efficiency of 89$%.

Co-design and qualitative validation of animated assessment item content for a child-reported digital distress screener

PurposeThe Interactive Child Distress Screener (ICDS) is a novel, digital screening tool that is currently under development and aims to broadly assess self-reported emotional and behavioural distress in children aged five to 11 years. This study implemented a generative participatory codesign and iterative refinement process to qualitatively validate the content of 30 animated assessment items developed for the ICDS by assessing their acceptability and accuracy from the child's perspective. MethodsThe participants (N = 62) were five to 11-year-old children. Individual interviews were conducted with each child to determine acceptability and validity of animated items and facilitate the co-design refinement process of the animated assessment items. ResultsTwenty-two out of 30 (73%) items met ≥80% satisfaction and accuracy consensus in their original format, six items (20%) required one round of refinement before meeting consensus, and two items (7%) required two rounds of refinements. Combined acceptability of animated items was high, ranging from 4.1 to 5 out of 5 across all items. ConclusionParticipants were able to accurately identify and understand socio-emotional and behavioural constructs when depicted as animated items. Acceptability was high, even in first iterations when accuracy of understanding required refinement. This study highlighted the importance and benefits of iterative participatory design methodology in ensuring assessment items developed for children are understood, accepted and likely to be effective in obtaining accurate self-report.

Iterative Method for Tuning Multiloop PID Controllers Based on Single Loop Robustness Specifications in the Frequency Domain

Multiloop proportional-integral-derivative (PID) controllers are widely used for controlling multivariable processes due to their understandability, simplicity and other practical advantages. The main difficulty of the methodologies using this approach is the fact that the controllers of different loops interact each other. Thus, the knowledge of the controllers in the other loops is necessary for the evaluation of one loop. This work proposes an iterative design methodology of multiloop PID controllers for stable multivariable systems. The controllers in each step are tuned using single-input single-output (SISO) methods for the corresponding effective open loop process (EOP), which considers the interaction of the other loops closed with the controllers of the previous step. The methodology uses a frequency response matrix representation of the system to avoid process approximations in the case of elements with time delays or complicated EOPs. Consequently, different robustness margins on the frequency domain are proposed as specifications: phase margin, gain margin, phase and gain margin combination, sensitivity margin and linear margin. For each case, a PID tuning method is described and detailed for the iterative methodology. The proposals are exemplified with two simulations systems where the obtained performance is similar or better than that achieved by other authors.

Household Energy Conservation Intervention: a Game versus Dashboard Comparison

This paper presents the results of a study, comparing a game versus a dashboard with respect to energy conservation in the household. In a pretest-posttest design, an empirical study tested whether change in attitude, knowledge, engagement and behaviour with respect to energy conservation in the household was different for participants playing Powersaver Game compared to a control condition where participants used an energy dashboard with the same content, but excluding game features. The aim of this game (developed using an iterative user-centered game design methodology) is to influence household energy consumption by means of electricity and gas usage in the long-term. The intervention time was at least 5 weeks and pre and post measures were based on 21 days intervals. All energy conservation activities that the application provides (e.g. washing clothes on low temperatures) take place in the real world and feedback is based on real time energy consumption. This real data into the game approach aims to optimize the transfer between the game world and the real world. Energy consumption significantly changed in the game condition compared to the control condition, and the difference between both conditions is more than 33% after the intervention. In the game condition, knowledge about energy conservation was significantly increased, although no significant differences in increase of attitude and engagement were found. We conclude that Powersaver Game is effective in transfer of energy conservation knowledge, which leads to energy saving behaviour on the long term. However, it cannot be concluded that playing the game leads to a greater change in attitude, probably because attitude scores of the participants were high from the start.

DEVELOPING A HEALTHCARE TECHNOLOGY: HOW WE ENGAGED RATHER THAN EXCLUDED OLDER ADULTS

AbstractRegular exercise and social engagement are essential to maintaining physical and cognitive independence and quality of life among older adults. However, frail and homebound older adults face incredible challenges to maintaining exercise and social engagement. Furthermore, the healthcare system does not currently offer long-term support for these activities. New technology has the potential to help connect frail older adults and their caregivers to rehabilitation and socialization in the home, but its development requires a unique approach for this audience. We will discuss how we have developed a technology-based solution targeting older adults and their caregivers to support long-term exercise and social engagement. We will share our iterative participatory design methodology that incorporated older adult and caregiver input during the design process, which helped make the product both relevant and user-friendly to targeted users.

Design of a Culturally-Informed Virtual Human for Educating Hispanic Women about Cervical Cancer.

Significant health disparities exist between Hispanics and the general US population, complicated in part by communication, literacy, and linguistic factors. There are few available Spanish-language interactive, technology-driven health education programs that engage patients who have a range of health literacy levels. We describe the development of an interactive virtual patient educator for educating and counseling Hispanic women about cervical cancer and human papillomavirus. Specifically, we describe the iterative design methodology and rationale, usability evaluation, and pilot testing of the system with Hispanic women in a rural community in Florida. The pilot study findings provide preliminary evidence of the feasibility of the proposed patient education approach. The proposed application and the lessons learned will prove beneficial for future work targeted towards different cultural populations.

Designing Helical Molecular Capsules Based on Folded Aromatic Amide Oligomers.

The ab initio rational structure-based design of a synthetic molecular receptor for a given complex biomolecular guest remains an elusive objective, yet remarkable progress has been achieved in recent years. This Account deals with the use of folded artificial aromatic amide oligomers, also termed aromatic foldamers, inspired from biopolymer structures, for the design of helical molecular capsules that can recognize guest molecules, completely surround them, and isolate them from the solvent, thus giving rise to a sort of guest encapsulation associated with slow binding and release kinetics. The development of new amino acid, diacid, and diamine monomers, a main source of creativity in this field, progress in their assembly into ever longer oligoamide sequences, and the predictability of the folded structures due to their inherent rigidity and simple folding principles, allowed for the design and preparation of unimolecular and bimolecular capsule shapes. These capsules consist of molecular helices having a large diameter in the middle and a narrow diameter at both ends thus creating a cavity suitable for binding a guest molecule. The understanding of molecular recognition properties within these bioinspired containers has greatly progressed. Recognition of simple guests such as diols or amino-alcohols may thus be predicted, and hosts can be proposed for guests as complex as saccharides using first principle design. Taking advantage of the modular nature of oligomeric sequences, of their synthetic accessibility and of their propensity to grow into crystals suitable for X-ray crystallographic analysis, a structure-based iterative design methodology has been developed that eventually yielded exquisite guest selectivity, affinity, and diastereoselectivity. This methodology involves rational negative design steps during which changes in the foldamer capsule sequence are not intended to improve binding to the targeted guest but instead to exclude the binding of other guests while preserving key interactions with the target. Metal ions can also be introduced at the inner rim of foldamer capsules and eventually assist the binding of an organic guest. These results demonstrate the viability of an ab initio approach to abiotic receptor design based on aromatic foldamers. The dynamic of the capsules associated with their self-organized nature provides opportunities to not only tune guest binding and selectivity, but also guest capture and release kinetics as well as cavity size and shape. Controlled release thus emerges as a realistic objective. Recent progress thus opens up multiple perspectives for the development of tailored hosts, sensors, and carriers structurally and conceptually different from earlier generations of macrocyclic-based receptors or from supramolecular containers produced by self-assembly.

Design automation of control panels for automated modular construction machines

Modern modular construction demands high quality, cost-effective, and efficient production of components. These requirements have led to the emergence of offsite construction manufacturing, which necessitates the use of automated machines. Compared to traditional onsite methods, offsite modular construction has a positive impact on quality, safety, cost, and productivity. Methodologies exist in the design of automated modular construction machines. This automation consists of not only the machines but also the supportive electrical and pneumatic systems, which, regardless of the design approaches used for automated machines, can be applied to the design of their associated systems. To avoid costly design changes, there is a clear need for a systematic and iterative design methodology at the conceptual design stage. For the control panel, the conceptual design method introduced in this paper facilitates the subsequent computer-aided design to be performed at the detailed design stage. Integrated function modeling, combined with axiomatic design and design structure matrix, constitutes the conceptual design approach for the control panel. In this work, linear time complex algorithm is developed for automating the layout of the electrical devices and wiring connections in order to facilitate computer-aided design implementation in the detailed design phase. Furthermore, the control panel guidelines and standards that constitute the prior knowledge of the design process are embedded in the algorithm.

IMPRESS BIM Methodology and Software Tools (iBIMm) for Façade Retrofitting Using Prefabricated Concrete Panels

IMPRESS is a H2020 funded project that has developed prefabricated façade panels to reduce building energy demand. In order to accelerate and optimise the retrofit process, IMPRESS has developed an iterative design methodology (IDM), which incorporates all stages of the design-construct-install-operate process and aims to bring energy efficiency as early as possible in the design process. Three software tools have been developed for this purpose: (1) an online decision support software (DSS), to inform decision-making on which panel type is suitable for the building; (2) an interoperable data exchange server (IDES) to allow exchange of information related to the design, construction, installation and operation of the facade; and (3) an online management platform (OMP) for coordination through all stages. The merger of the design methodology and software tools is called IMPRESS BIM methodology (iBIMm) which enables design teams to make informed decisions based on building information models and provides a platform to monitor its performance during the operation stage.

Design Sensitivity Analysis of a Plate-Finned Air-Cooled Condenser for Low-Temperature Organic Rankine Cycles

ABSTRACTDue to increasing world energy demand and environmental concerns, sustainable energy production has become crucial. Among sustainable energy sources such as solar, wind, and geothermal, industrial waste heat (heat normally released to the environment) has a big potential. Organic Rankine cycles (ORCs) are promising systems for utilizing low-temperature (100–250°C) waste heat. For an ORC system, the condenser is a key component. An accurate condenser design is important for cycle efficiency and system cost. In the literature, there are in-tube condensation correlations that are used to design condensers. However, they are not necessarily valid for low-temperature ORC conditions and working fluids, and that might lead to inaccurate end designs. This study comprises a summarized literature survey about in-tube condensation correlations. Then an iterative heat exchanger design methodology is proposed that allows performing a design sensitivity analysis on a V-shaped condenser within an input range of geometric parameters and boundary conditions. Nineteen correlations are implemented to calculate rating parameters like pressure drops, total transferred heat, overall heat transfer coefficient, size, cost and degree of subcooling. The deviations at these parameters are represented as the coefficient of variation that indicates the design condition regions where the prediction methods differ or not.