Basis For Design Research Articles

Brain-computer interface based generative design framework: an empirical multi-domain application exploration based on human-factors and form-generation interactive mechanisms

Human experience in an architectural space is defined as the state of mind that is reflected on their physiological, emotional, and cognitive statuses. Ergonomic data, as an objective manifestation of quantifiable signals generated by the human body during specific spatial perception processes, serves as a vital foundation for spatial evaluation and guidance for optimization. Electroencephalogram (EEG) signals, as quantifiable sensory indicators directly arising from the interaction between individuals and external stimuli, hold substantial potential as a data-driven force and as a means of optimization assessment in the study of generative design. Although existing research has effectively established a unidirectional relationship between EEG and spatial-environment assessment, there is still a notable deficiency in addressing the creation of a two-way, mutually informative feedback mechanism. This study investigates the applicability of EEG signals as a data-driven basis for generative design across universal methods. It delves into various scales and scenarios of digital design, from the microscopic to the macroscopic, encompassing planar and volumetric visual elements, the design of architectural spatial environmental characteristics, and urban space design grounded in human perceptual sightlines. The research examines the viability and appropriateness of an interactive generative design method based on form generation, predicated on human-factor physiological data exemplified by EEG signals. This paper initially conducts a methodological and tool-based examination of current research in ergonomics-driven design and the use of EEG for design assessment, thereby discussing the objective feasibility of employing EEG in interactive generative design. Subsequently, the study establishes an integrated data flow system encompassing multiple hardware and software components to form a comprehensive workflow. Following this setup, empirical studies based on this method are conducted at different scales of application, yielding corresponding form-generative outcomes. Finally, this paper substantiates the rationality and feasibility of this framework in multi environment design domains.

Microstructured Cantilever Probe on Optical Fiber Tip for Microforce Sensor

Benefiting from the great advances of the femtosecond laser two-photon polymerization (TPP) technology, customized microcantilever probes can be accurately 3-dimensional (3D) manufactured at the nanoscale size and thus have exhibited considerable potentials in the fields of microforce, micro-vibration, and microforce sensors. In this work, a controllable microstructured cantilever probe on an optical fiber tip for microforce detection is demonstrated both theoretically and experimentally. The static performances of the probe are firstly investigated based on the finite element method (FEM), which provides the basis for the structural design. The proposed cantilever probe is then 3D printed by means of the TPP technology. The experimental results show that the elastic constant k of the proposed cantilever probe can be actively tuned from 2.46 N/m to 62.35 N/m. The force sensitivity is 2.5 nm/µN, the Q-factor is 368.93, and the detection limit is 57.43 nN. Moreover, the mechanical properties of the cantilever probe can be flexibly adjusted by the geometric configuration of the cantilever. Thus, it has an enormous potential for matching the mechanical properties of biological samples in the direct contact mode.

Fracture behavior and mechanism of highly fragmented steel cylindrical shell under explosive loading

An in-depth understanding of the fracture behavior and mechanism of metallic shells under internal explosive loading can help develop material designs for warheads and regulate the quantity and mass distribution of the fragments formed. This study investigated the fragmentation performance of a new high-carbon silicon-manganese (HCSiMn) steel cylindrical shell through fragment recovery experiments. Compared with the conventional 45Cr steel shell, the number of small mass fragments produced by the HCSiMn steel shell was significantly increased with a scale parameter of 0.57 g fitted by the Weibull distribution model. The fragmentation process of the HCSiMn shell exhibited more brittle tensile fracture characteristics, with the microcrack damage zone on the outer surface being the direct cause of its high fragmentation. On the one hand, the doping of alloy elements resulted in grain refinement by forming metallographic structure of tempered sorbite, so that microscopic intergranular fracture reduces the characteristic mass of the fragments; on the other hand, the distribution of alloy carbides can exert a "pinning" effect on the substrate grains, causing more initial cracks to form and propagate along the brittle carbides, further improving the shell fragmentation. Although the killing power radius for light armored vehicles was slightly reduced by about 6%, the dense killing radius of HCSiMn steel projectile against personnel can be significantly increased by about 26% based on theoretical assessment. These results provided an experimental basis for high fragmentation warhead design, and to some extent, revealed the correlation mechanism between metallographic structure and shell fragmentation.

Hysteretic behavior and moment-rotation model of self-centering beam-column connection with angle steel

The objective of this study is to develop a moment-rotation model (M-θ) to evaluate the hysteresis behavior of self-centering beam-column connection with replaceable angle steel. Based on the previous pseudo-static test results of 13 groups of 22 beam-column joint specimens, the hysteretic behavior of the joint and the prestress loss of the post-tensioned (PT) strand are further studied. According to the phased hysteretic characteristic of the beam-column joint and the connection characteristic of two interfaces, the M-θ model for beam-column connection is established, which is divided by four key points: opening point, yield point, peak point and ultimate point. The proposed M-θ model includes the bilinear moment-rotation (M-θs) model of the endplate-bolt interface based on the component method, and the trilinear moment-rotation (M-θr) model of the self-centering interface considering the prestress loss of PT strand and the phased mechanical behavior of each component. The accuracy of the proposed M-θ model is verified by the comparisons of theoretical calculation results and experimental skeleton curves, which provides a theoretical basis for the engineering design of this kind self-centering beam-column connection.

Study of cathode emission surface defects in relativistic magnetrons

The cathode emission surface (CSD) defect is one of the main reasons for the performance difference in relativistic magnetron multiple pulses operation, but its impact mechanism is unclear. In this work, the kinetics model and the particle in a cell method were used to explain the influence of the emission defect effect. The results indicate that the CSD effect causes deformation of the electron sheath and reduces the current. The emission defects in the azimuthal direction −π/2<nφ*<π/2 region favor the electron bunching. Moreover, the emission defects on the cathode side near the accelerator in the axial direction weaken the axial drift issues. Our work will provide a basis for the large-area cathode design and facilitate the relativistic magnetron experimental analysis.

Surface wettability-induced modulations of droplet breakup in a bifurcated microchannel

We explore the dynamics of droplet propagation and subsequent disintegration in a symmetric bifurcating Y-microchannel by varying the wettability characteristics of one of the daughter channels while maintaining the wettability of the other constant. The temporal evolution of the droplet is numerically investigated using the phase-field method. Based on the neck-width evolution, the droplet bifurcation phenomenon has been divided into three separate stages, namely, squeezing, transition, and pinch-off. During the squeezing stage, the rate of change of neck width increases as the wettability angle decreases, while an opposite trend is observed at the pinch-off stage, leading to almost identical breakup time for the droplet regardless of the wettability angle. We identify pertinent regimes of droplet breakup, such as symmetric breakup, asymmetric breakup, no-breakup upper channel, no-breakup lower channel, and spreading regime, over wide ranges of capillary numbers (Ca) and viscosity ratio (μr). Our study indicates that an increase in the relative influence of viscous force (high Ca) reduces the droplet's wettability effect. The same pattern is obtained when the viscosity of the droplet is increased in relation to the viscosity of the carrier fluid. In contrast, for low Ca flows, the relatively strong interfacial tension favors the wettability characteristics of the surface, resulting in a dominance of non-breakup regimes. The regime plots proposed in this paper depict the roles of Ca and μr on various breakup regimes in detail. Such regime diagrams may emerge as fundamental design basis of microfluidic devices in diverse applications, such as biopharmaceuticals, microreactors, and food processing.

A multimodal precision-prevention approach combining lifestyle intervention with metformin repurposing to prevent cognitive impairment and disability: the MET-FINGER randomised controlled trial protocol

BackgroundCombining multimodal lifestyle interventions and disease-modifying drugs (novel or repurposed) could provide novel precision approaches to prevent cognitive impairment. Metformin is a promising candidate in view of the well-established link between type 2 diabetes (T2D) and Alzheimer’s Disease and emerging evidence of its potential neuro-protective effects (e.g. vascular, metabolic, anti-senescence).MET-FINGER aims to test a FINGER 2.0 multimodal intervention, combining an updated FINGER multidomain lifestyle intervention with metformin, where appropriate, in an APOE ε4-enriched population of older adults (60–79 years) at increased risk of dementia.MethodsMET-FINGER is an international randomised, controlled, parallel-group, phase-IIb proof-of-concept clinical trial, where metformin is included through a trial-within-trial design. 600 participants will be recruited at three sites (UK, Finland, Sweden). Participants at increased risk of dementia based on vascular risk factors and cognitive screening, will be first randomised to the FINGER 2.0 intervention (lifestyle + metformin if eligible; active arm) or to receive regular health advice (control arm). Participants allocated to the FINGER 2.0 intervention group at risk indicators of T2D will be additionally randomised to receive metformin (2000 mg/day or 1000 mg/day) or placebo. The study duration is 2 years. The changes in global cognition (primary outcome, using a Neuropsychological Test Battery), memory, executive function, and processing speed cognitive domains; functional status; lifestyle, vascular, metabolic, and other dementia-related risk factors (secondary outcomes), will be compared between the FINGER 2.0 intervention and the control arm. The feasibility, potential interaction (between-groups differences in healthy lifestyle changes), and disease-modifying effects of the lifestyle-metformin combination will be exploratory outcomes.The lifestyle intervention is adapted from the original FINGER trial (diet, physical activity, cognitive training, monitoring of cardiovascular/metabolic risk factors, social interaction) to be consistently delivered in three countries. Metformin is administered as Glucophage®XR/SR 500, (500 mg oral tablets). The metformin/placebo treatment will be double blinded.ConclusionMET-FINGER is the first trial combining a multimodal lifestyle intervention with a putative repurposed disease-modifying drug for cognitive impairment prevention. Although preliminary, its findings will provide crucial information for innovative precision prevention strategies and form the basis for a larger phase-III trial design and future research in this field.Trial registrationClinicalTrials.gov (NCT05109169).

Parameters collaborative optimization design and innovation verification approach for fuel cell distributed drive electric tractor

Fuel cell distributed drive electric tractors (FCDET) are one of the necessary means to achieve truly green agriculture. However, low traction efficiency, poor control coordination, and excessive energy consumption are the main reasons hindering the industrialization of FCDET. This paper proposed a parametric collaborative optimization design method and innovative verification system that considers the drive system and energy system. Based on the tractor plowing operating conditions, a 7-DOF coupled dynamics model of the distributed drive system and a tire-soil interaction model were established, and the key component selection and parameter matching were completed. On the drive system optimization level, the front and rear wheelside transmission ratios are optimized based on a multi-island genetic algorithm (MIGA). On the energy system optimization level, the globally optimal power distribution ratio is found based on the dynamic programming algorithm (DP). A complete experimental prototype verification system is constructed based on the MATLAB/Simulink-NI PXI joint simulation platform, physical prototype test bench, and real vehicle multi-index test platform. The results show that the average efficiencies of the optimized drive and energy system are increased by 0.38 % and 3.82 %, the total energy consumption (total hydrogen consumption) is reduced by 25.40 % and 15.39 %, respectively. The maximum fault-free operating time is 5.5h, the average traction power is 21.07 kW, and the average traction force is 10610 N in the all-wheel drive mode. The experimental results fully demonstrate that the electric tractor with the fuel cell distributed drive system as the core can meet the verification of multiple indicators. This study can provide a new theoretical basis and technical verification method for the optimal design and system control of fuel cell distributed drive electric tractors.

A Web-based Computerization Tool Environment for Smart Motor controller Deployment

Abstract: India has a vast variety of irrigational settings and conditions due to its geographically diverse terrain. A government survey conducted in India indicates that 75% of people live in rural regions where farming is the primary source of income. Recent studies demonstrate that globalisation and resource scarcity have led to a significant change in weather patterns, which has a detrimental impact on farming. Inefficient irrigation systems, losses, improper techniques, etc. are the primary issues that hasten the deterioration of agricultural conditions. Farming is quite labor-intensive and needs the physical presence of the farmer using the existing irrigation system. We investigated the problems farmers faced and offered them an inexpensive, lowmaintenance irrigation option. Sometimes the system's power supply was timed incorrectly, making the conditions too unpleasant and dangerous for field irrigation. In order to control the functioning of water irrigation systems using automated AC motor starters, we use an already-existing WiFi network. The fundamental timer-based Starter Automation Structure forms the basis of the whole design. The principal objective of this design is to limit design criticality, hence enabling straightforward maintenance and repair.

Reliability index of a pipe transporting hydrogen submitted to seismic displacement

The reliability index was determined for a pipe presenting a corrosion defect, subjected to an internal hydrogen pressure, buried in a soil with a reaction and subjected to displacement due to seismic activity. The results are obtained by calculating the failure condition: strain demand greater than strain resistance, which is usually the basis of local strain-based design (LSBD). From a probabilistic point of view, this condition results from the product of the two probability distributions, Demand and Resistance. The Resistance is assumed to follow a normal distribution. The strain Demand is calculated assuming that the earthquake probability density follows a Gutenberg–Richter distribution. The reliability index is calculated by analytical method. This method is used to predict the reliability index of three different reference periods or seismic zones located in France.

Dynamic response and wave motion of a periodically supported beam under an ultra-high-speed load: Wave dispersion and critical velocities

Vacuum tube transportation system is an attractive transportation mode due to the ultra-high-speed (over 1000 km/h) it can reach. Most vacuum tube transportation systems, e.g., the Hyperloop operate in elevated tube structure on periodical supports. When the speed of the vehicle reaches certain critical values, the periodical supporting structure experiences resonance-like response whose vibrational magnitude is significantly amplified. The amplification of the response has an adverse impact on the safety of the vehicle operation and severability of the supporting structures. This work aims to boost the fundamental understanding of the underlying physical mechanism of wave motions and critical velocities in the “moving load on periodical structure” problem utilizing an ultra-high-speed Hyperloop-type transportation system as an example. In this work, an ultra-high-speed moving load on a periodically supported beam is used to model the dynamic response of the supporting structure under an ultra-high-speed travelling vehicle. The steady-state response of the periodically supported beam is solved analytically and illustrated for sub- and trans-critical speeds. The dispersion relation is obtained while deriving the steady-state response. The relation between wave propagation in a periodical structure and critical speeds of the moving load on it is established. It is shown that the critical speeds could be within the operational speed range of ultra-high-speed transportation system. The number and magnitude of critical speeds are closely related to wave motions in the periodically supported structure. It is found that the primary critical speeds associated with largest beam responses may not exist, depending on the relative flexibility of the supports. The optimal structural parameters are associated with wave motion transition (between Local Resonance and Bragg Scattering) in the supporting structure. With this simplified model, wave motions in a periodical structure and critical speeds of the moving load on it is explained in a general physical sense. This work provides theoretical basis for the structural design and operation of the ultra-high-speed transportation system, as well as other engineering applications in which ultra-high-speed moving load is involved.

Assessment of combined passive cooling strategies for improving outdoor thermal comfort in a school courtyard

Both artificial shading and evaporative cooling have proven to be effective strategies for improve outdoor thermal comfort. However, their combined effect on microclimates or thermal sensations has rarely been investigated, hindering our understanding of the interactions among cooling strategies. In this study, we tested the performance of sun sails with different coverage ratios, mist-spray systems with different nozzle arrangements, and a combination of these two strategies for cooling a kindergarten courtyard using validated ENVI-met models. Among the strategies, we found that the shade + mist strategy is the most effective and can reduce the physiological equivalent temperature (PET) by up to 14.43 °C and heat stress levels by 2–3 categories in originally exposed areas. This was followed by the sun sail shading strategy. The mist-spray system had a relatively weak cooling effect. The cooling effects of sun sails increased with coverage ratios and mounting heights, whereas the spatial cooling distribution of mist spraying was mainly determined by wind rather than by nozzle arrangements. In addition, we found that shading can enhance the cooling effect of mist spraying in terms of air temperature, but reducing its cooling effect in terms of the mean radiant temperature. Our results highlight a great potential of comprehensively using multiple strategies to improve outdoor thermal comfort, and provide a design basis for enhancing thermal comfort in similar school courtyards in Hunan Province in China.

Evaluation Method and Analysis on Performance of Diffuser in Heat Storage Tank

The diffuser is a critical component in a heat storage tank, and its structure has an important influence on the thermal performance of the heat storage tank. At present, research on the structure of diffusers often focuses on the change of one single parameter, which results in the need for a comprehensive structure analysis of diffusers in heat storage tanks. This paper comprehensively considers the inlet diameter, hole distance, and hole diameter of the diffuser and the inlet conditions of the heat storage tank. Then, a new evaluation index, namely the non-uniformity coefficient of the diffuser, is proposed. The experiments verify the accuracy of numerical calculation, and the related empirical formula is summarized finally. The results show that the diffuser with a small non-uniformity coefficient can achieve thin temperature stratification and higher exergy efficiency. In other words, the non-uniformity coefficient is in good agreement with temperature stratification and the exergy efficiency of the heat storage tank. When the flow rate of the inlet device is 0.5 m/s, the exergy efficiency increases by nearly 30 percentage points and the non-uniformity coefficient of the No. 4 diffuser is 3.39%. In contrast, that of the No. 8 diffuser is 75.17%. This evaluation index is suitable for different diffuser types with high accuracy. It provides the theoretical and experimental basis for the structural design and selection of diffusers for heat storage tanks.

Research Advances in Rare Earth Oxide‐Based Catalysts for Soot Combustion

AbstractEnvironmental issues exert a significant influence on the human life. Soot particles have attracted attention as a major source of pollution. Significant progress has been made in the research of efficient soot combustion catalysts. The distinctive bonding properties on the 4 f orbitals of rare earth elements exhibit excellent catalytic performance for soot combustion. This comprehensive review explores recent advancements in the design of catalysts based on rare earth oxides, with a specific focus on various catalytic materials (La‐based, Ce‐based, Pr‐based and other rare earth elements), synthesis methods, catalyst morphology, catalytic performance and the intricate mechanisms governing their performance in catalytic soot combustion. The activity and selectivity of different rare earth catalysts in various reaction atmospheres are also summarized in the article. Finally, the challenges associated with rare earth oxide‐based catalysts and their potential for future development in the soot combustion are highlighted. This review establishes a fundamental basis for the further design of catalytic materials that exhibit enhanced efficiency and stability.

A simple filter Lorenz electronic circuit

In this work, an electronic circuit of the Lorenz system is developed. The electronic circuit proposed is one of the easiest to implement. We changed the x-state equation of Lorenz‘s system with a low-pass filter to an RC circuit with the same cutoff frequency. Corron‘s electronic circuit is used as the basis for electronic design. Simulation results support this proposal.

Modeling of flexible bevel gear rotor systems: Modal and dynamic characterization

Bevel gears, a crucial part of aircraft transmission systems, are more susceptible to wheel body vibration issues as lightweight requirements rise. In the past, the gear wheel body was often considered rigid while assessing the dynamic properties of gear systems. Constructing a bevel gear model with a thin-walled structure might not be appropriate for this modeling technique; this research suggests a dynamic model that considers the flexibility of bevel gears. The web and teeth structure of the gear are preserved by realistic modeling using three-dimensional hexahedral components. The component mode synthesis (CMS) approach reduces the model order for increased computational efficiency. To confirm the accuracy of the modeling method, the modal frequencies and vibration shapes of the proposed model single-gear shaft are compared with results from experiments and ABAQUS. By contrasting ABAQUS system-level meshing modal frequencies and vibration shapes, the accuracy of the system model assembly is further confirmed. The model examines the impact of bevel gear flexibility on the modal frequencies, modal vibration shapes, and system dynamic properties. The mode shape diagram at dangerous modal frequencies found using the modal strain energy technique and the vibration displacement cloud maps at resonance speeds computed using the Newmark-β method are mutually verified, and this demonstrates that lightweight bevel gears are more susceptible to excitation due to nodal diameter type vibrations. Proposed and traditional models anticipate substantially different resonance speeds since the traditional model assumes that the gear, being a rigid disk, can only excite the shaft's bending mode of vibration. The proposed model provides a more comprehensive description of the dynamic characteristics of bevel gear systems, providing a theoretical basis and optimization tool for the high-performance design, vibration reduction, and noise control of high-speed lightweight gear transmission systems.

Incorporation of total ionizing dose effects into a compact model for p-GaN gate high electron mobility transistors

Total ionizing dose (TID) characteristics of p-GaN gate high electron mobility transistors (HEMTs) under different bias conditions are explored in this work. Potential mechanism accounting for the TID response of p-GaN gate HEMTs is analyzed, based on which a TID effects model is developed. The TID effects model describes the relationship among threshold voltage of p-GaN gate HEMTs, total radiation dose, and electric field inside the p-GaN cap layer. Furthermore, an approach incorporating the TID effects model into Advanced Spice Model for HEMT (ASM-HEMT) is proposed, the reliability of which is validated by the well-fitted modeled results in comparison with the measured ones. This approach makes it possible to probe into the impact of TID effects on p-GaN gate HEMTs from the perspective of circuit level, which provides a basis for the follow-up GaN-based circuit design.

Balancing Performance Trade-offs in Modern Sorting Methodologies

The study of sorting algorithms has always been a key topic. This paper thoroughly explains and investigates the time complexity of six classic sorting algorithms through theoretical analysis and experimental comparison. We implemented insertion sort, selection sort, bubble sort, shell sort, quicksort, and heapsort. By controlling data scale and distribution, we systematically tested the performance of different algorithms under various scenarios. The results show that there are significant efficiency differences between algorithms on small-scale data, and the advantages of quicksort and heapsort become more obvious as data size increases. Through extensive comparative experiments, this paper identifies the application scenarios of each algorithm, providing a theoretical basis for algorithm design and selection.

Influence of diamond-like carbon coatings and micro-texturing on friction and wear of seal interfaces: Experiment and simulation study

For mechanical seal friction vice in dry friction conditions, due to friction wear serious failure, is the slurry pump and other instruments in the operation of the process of the urgent need to solve the problem. In this paper, in order to optimize and enhance the friction and wear problem of mechanical seal end face of slurry pump. Surface treatment of mechanical sealing rings with diamond-like carbon (DLC) coating and surface microtexturing, and at different rotational speeds and normal forces, the surface hardness, wear coefficient and dry friction coefficient of the sealing rings were analyzed by experimental comparison, and the wear morphology was collected by electron microscopy, having analyzed the results of the sets of, the end face structure of the mechanical seal was optimized. Based on Archard wear model simulation calculations, the seal ring wear depth and wear quality were obtained. The results show: under dry friction conditions, the synergistic effect of the DLC coating and the surface micro-texture (MT), the coefficient of friction is reduced by approx. 68% and the quality and depth of wear is minimized. Excessive speeds and normal forces are more prone to wear behavior caused by abrasive wear. Simulation results of surface treatment groups, DLC / MT group maximum wear depth is the smallest; wear quality test and simulation of the maximum error within 15.7%. The results of the study can provide a basis for a phosphoric acid plant slurry pump mechanical seal design.

Experimental testing of spliced glulam joints for large-span timber structures

In recent years, wood has become an increasingly popular building material for its environmental friendliness. Large-span timber structures are in high demand, of which the spliced joints play an important role for the main structural members. In this research, six specimens with two connection configurations, i.e., the slotted-in-steel-plate connection (SC) and the cover-plate connection (CC), were designed and subjected to cyclic loading tests. Besides the traditional data acquisition system, contact-free displacement measurement was also applied. The feasibility was verified since the moment-rotation curves obtained through the two methods showed strong consistency. Through the analysis of the mechanical properties of the joints, different methods for the determination of the yielding point of the specimens were compared and discussed. The test results show that the ultimate strength and stiffness of the CC connection were 59.04% and 187.7% higher than that of the SC connection, whereas the ductility of the former was 77.02% lower than that of the latter. Factors influencing on their mechanical properties were further analyzed. It is noted that while the ultimate strength is dominated by the steel plates, the stiffness and ductility depend more on the glulam elements and fasteners. Recommendations were also proposed as a design basis for the two types of connections.