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Understanding Cognitive Impacts of Robots in Worker-Robot Collaboration in Modular Construction
No full textHuman-robot collaboration (HRC) holds significant potential to enhance productivity and efficiency in modular construction (MC). While existing studies in construction HRC have predominantly focused on technical advancements, limited attention has been paid to human factors and the cognitive impacts of robots on workers during collaboration. This study addresses this gap through an experimental investigation. A controlled experiment was conducted to compare conditions with and without a collaborative robot (cobot). Work performance metrics (e.g., time efficiency, angular accuracy, and screwing quality) and human factors (e.g., fatigue levels, individual effort, and stress states) were assessed using statistical analysis and self-report questionnaires. Results of work performance indicate that cobot integration significantly increased task completion time (TCT) (Est. = 0.314, t = 5.18, p \u3c 0.001), with variations observed across tasks (p = 0.00452). Results of human factors revealed increased fatigue (mean scores rising from 18.9 to 22.0), mental effort (mean scores rising from 40.2 to 50.1), and distress (mean scores rising from 12.2 to 15.9) under the cobot condition, suggesting additional cognitive demands during collaboration. These findings underscore the importance of addressing task complexity and cognitive challenges when implementing cobots in MC workflows. This research contributes to advancing robotics integration and safeguarding worker well-being in modular construction
Dimensional Stability of Scots Pine Sapwood Modified by Tannin-Based Formulas
No full textThis study was conducted to evaluate the physical and chemical properties of Scots pine (Pinus sylvestris L.) sapwood modified with tannin-based formulas. Wood samples were pressure impregnated with tannin solution at five different concentrations of citric acid (0, 2, 10, 20, and 40 wt/wt%). The tannin-modified samples were analyzed by mean of their weight percentage gain (WPG), leaching resistance (LR), bulking coefficient (BC), anti-swelling efficiency (ASE), Fourier-Transform Infrared (FTIR) spectroscopy, and optical microscopy, and the results were compared with unmodified sapwood and heartwood samples. It is observed that the WPG and dimensional stability of the samples increased with increasing the citric acid (CA) concentrations and the highest WPG was attained (44%) with a formulation containing 20% CA while, the BC, LR, and ASE values were considerably higher in the samples modified with 40% CA concentration as compared to other modification formulas and also the unmodified sapwood and heartwood samples. FTIR spectroscopy analyses showed higher esterification degree with higher concentrations of CA. Overall, this study suggests the potential of a fully bio-based tannin formula to improve the water-related properties of Scots pine sapwood
Decadal Changes in Ground-Layer Plant Communities Reflect Maple Dieback and Earthworm Invasion in National Forests in the Lake Superior Region, USA
Get PDFNorthern hardwood forests of the Lake Superior region face a series of novel disturbance pressures including canopy dieback. Previous studies have linked regional sugar-maple (Acer saccharum) canopy dieback to introduced earthworms, which may have coinciding impacts on the ground-layer plant community. Dieback–earthworm interactions may lead to important longer-term changes in forest structure and function, but these relationships but have not been characterized. We sampled ground-layer plant communities in five national forest units in Michigan, Wisconsin, and Minnesota in 2010, and again just over a decade later in 2021. Non-metric multidimensional scaling ordination and indicator species analysis were used to assess relationships among ground-layer community composition and structure, functional traits, and environmental gradients including forest-floor condition and A. saccharum canopy dieback. Increases in dieback and earthworm disturbance in the decade between inventories were accompanied by a marked divergence in observed ground-layer plant community structure between national forests. Ordinations of 2021 data indicated a strengthening relationship between forest-floor condition and earthworm abundance. Our results suggest that earthworm impacts and A. saccharum dieback are driving changes in the ground layer on broad geographic and temporal scales, with short- and long-term implications for plant-community structure and function, and higher trophic levels
Data supporting “Large aerosol particles favor haze conditions through limitations on water budget and activation kinetics”
No full textExperiments in the Pi Convection-Cloud Chamber conducted by systematically changing the diameter of injected dry aerosol particles while holding the temperature gradient constant demonstrate that dry diameter strongly influences the onset of haze-dominated conditions. Two factors contribute: the system becomes water-limited, resulting in reduction of supersaturation by growing aerosol particles to the activation diameter; and the activation process becomes kinetically limited. Aerosol dry diameter exerts a strong influence on activation time, with a power-law exponent of 9/2. Kinetically-limited activation occurs when the ratio of the activation and droplet residence times is greater than unity. The findings demonstrate that a haze-dominated state, where cloud formation is suppressed, can be achieved not only with weak supersaturation forcing and high aerosol concentration but also with large, hygroscopic aerosol particles. These results have implications for cloud formation in polluted environments, fog development near the ocean, and hygroscopic cloud seeding
Resilience Oriented Distribution System Service Restoration Considering Overhead Power Lines Affected by Hurricanes
Get PDFIn recent years, there has been an increase in the frequency of severe weather events (like hurricanes). These events are responsible for most power outages in power distribution systems (PDSs). Particularly susceptible to storms are overhead PDSs. In this study, the dynamic Bayesian network (DBN)-based failure model was developed for different hurricane scenarios to predict the line failure of overhead lines. Based on the outcomes of the DBN model, a service restoration model was formulated to maximize restored loads and minimize power losses using Particle Swarm Optimization (PSO)-based distributed generation (DG) integration and system reconfiguration. Three different case studies based on the IEEE 33 bus system were conducted. The overhead line failure prediction and service restoration model findings were further used to calculate resilience metrics. With reconfiguration the load restored from 90.3% to 100% for Case 1 and from 34.994% to 80.35% for Case 2. However, for Case 3, reconfiguration alone was not sufficient to show any improvement in performance. On the other hand, DG integration successfully restored load to 100% in all three cases. These results demonstrated that the combined DBN-based failure modeling and PSO-driven optimal restoration strategy under hurricane-induced disruptions can effectively strengthen system resilience
Investigating the Impacts of Agrivoltaic Design Choices on Inter-Row Shading and Electricity Production
No full textNo Abstract available
Experimental and numerical investigation of concrete properties and crack propagation in concrete incorporating different sizes of recycled tire rubber particles
No full textThe increasing volume of waste tire rubber poses serious environmental challenges, motivating its use in concrete for sustainable construction. This study examines the effects of recycled rubber particle size and content on the mechanical and durability performance of concrete, using coarse and fine rubber as partial fine aggregate replacements. Experimental evaluations included compressive and tensile strength, flexural behavior, ultrasonic pulse velocity, drying shrinkage, and freeze-thaw resistance. Microscopy and Discrete Element Method (DEM) simulations were conducted to investigate internal fracture behavior. Results show that rubber incorporation reduces mechanical strength due to low stiffness and weak interfacial bonding. However, concrete modified with fine rubber exhibited better strength retention, improved stress distribution, and enhanced microstructural integrity, attributed to improved packing density, reduced porosity, and more uniform shrinkage behavior. Freeze-thaw tests demonstrated greater resistance to expansion and superior durability. Microscopy observations and DEM simulations further revealed a more stable load transfer network and lower stress concentrations in fine rubber mixtures locally by comparing to coarse rubber counterparts. These findings suggest that fine recycled rubber improves fracture toughness and durability, supporting its potential as a sustainable alternative material for concrete infrastructure
Selective Extraction of Nickel and Cobalt from Serpentine Minerals Using Carbon-Negative Carbonation-Assisted Leaching Technology
No full textSerpentine is a group of hydrous magnesium–iron phyllosilicate minerals that contain both nickel (Ni) and cobalt (Co). To date, the extraction of both Ni and Co from nickel-bearing serpentine minerals has been technologically challenging and economically unviable. In this work, a carbon-negative leaching technology was developed to extract Ni and Co from serpentine-rich rocks while simultaneously sequestering CO2in the form of carbonate minerals. The conversion of serpentine to olivine using thermal activation was investigated under air and hydrogen environments. Lab-scale carbonation-assisted leaching trials showed that the hydrogen dehydroxylation process effectively transformed serpentine to olivine, increased the porosity of the feed minerals, and thereby enhanced the mineral carbonation efficiency. The carbonation efficiency reached 86%, with Ni and Co extraction rates of 80% and 75%, respectively, after 2 h. The carbonation efficiency was found to correlate strongly with the metal extraction efficiency, indicating that the limiting factor was the dissolution and release of divalent ions from the silicate mineral. Under optimal conditions, the activated serpentine mineral exhibited a CO2uptake capacity of 357 kg per ton of feed, with approximately 2.63 kg of nickel and 0.43 kg of cobalt recoverable per ton of the feed. These findings illustrate the viability of hydrogen dehydroxylation coupled with carbonation-assisted leaching technology to unlock critical minerals from unconventional low-grade nickel ore resources
Examining Student Resolutions of Automated Critiques
No full textThis study examines the critique resolution strategies employed by students in introductory computer science and engineering courses when responding to automated critiques of their code. Drawing on data from both Computer Science (CS) and Engineering Fundamentals (EF) students using an automated feedback system, we investigate how students adapt their coding behavior in response to critiques and how these adaptations evolve across multiple submissions. The tool we have developed is a code critiquing tool that provides real-time feedback on syntax, logic, and stylistic errors in student code, designed specifically for educational environments. Through a multi-semester analysis of student behavior data, we evaluate the comparative performance of students enrolled in CS and EF courses and their approaches to resolving critiques. This cross-disciplinary comparison illuminates distinct patterns of problem-solving, engagement, and learning between students of varying technical backgrounds. The data for this study is drawn from three semesters of course assignments where the critiquer system was deployed in both CS and EF courses. Each submission was automatically logged by the critiquer system, capturing data such as time between submissions, antipattern identification, critique counts, and time to critique resolution. The behavioral patterns are analyzed by assignment, allowing us to assess trends over time and across multiple academic disciplines. By understanding how students from different disciplines engage with automated feedback, we can tailor these tools more effectively to meet the diverse needs of learners. These insights have implications for both the design of automated feedback systems and the pedagogical strategies employed in introductory programming courses. The study further proposes enhancements to the critiquer system that include customizable feedback options for different educational contexts and improved usability for both students and instructors
The Effects of Green Orientation and Technological Agility on Sustainable Competitive Advantage under Environmental Uncertainty: Organizational agility as a pathway
No full textDespite the strengthened efforts on sustainability and technological activities by firms, the existing literature lacks a clear picture regarding how green orientation (GO) and technological agility (TAG) can be transformed into sustainable competitive advantage (SCA) and at what time the conversion process may be most efficient. This paper conceptualizes organizational agility (OGA) based on the resource-based view (RBV) and dynamic capabilities theory (DCT) and hypothesizes that GO and TAG indirectly affect SCA with the mediating impact of environmental uncertainty (ELU). A moderated-mediation model was tested based on a sample of 200 managers (HR, marketing, accounting/finance, quality control, R&D) of auto-parts manufacturers in industrial clusters in Gujarat, India, and measured with PLS-SEM. The findings indicate that GO and TAG have positive effects on OGA and SCA and that OGA plays a significant mediation role in the association of GO and SCA, as well as TAG and SCA. Nevertheless, the conditional indirect hypothesis effects of ELU were not significant and indicated that the routinized agility could shield the firms against the legitimacy turbulence in the process of transforming the sustainability intent and technological responsiveness into competitive results. The research makes a contribution to theory by explaining how the effects of orientations make sense when beneficial and defining a condition of what might be termed a limit in which the capability effects are enhanced. On the managerial front, it emphasizes the aspects of co-investment of GO and TAG along with the institutionalization of agility routines to achieve sustainability-driven competitiveness in dynamic markets