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Design of a Novel Tomato Harvesting Gripper
Get PDFThe robotic harvesting of tomatoes in a greenhouse setting presents many challenges in grasping, separation and manipulation of the produce. Presented is the design and development of a tomato harvesting tool, using a minimal amount of sensors and actuators to overcome the associated challenges
A systematic review of predictive, optimization, and smart control strategies for hydrogen-based building heating systems
Get PDFThe use of energy in the built environment contributes to over one-third of the world's carbon emissions. To reduce that effect, two primary solutions can be adopted, i.e. (i) renovation of old buildings and (ii) increasing the renewable energy penetration. This review paper focuses on the latter. Renewable energy sources typically have an intermittent nature. In other words, it is not guaranteed that these sources can be harnessed on demand. Thus, complement solutions should be considered to use renewable energy sources efficiently. Hydrogen is recognized as a potential solution. It can be used to store excess energy or be directly exploited to generate thermal energy. Throughout this review, various research papers focusing on hydrogen-based heating systems were reviewed, analyzed, and classified from different perspectives. Subsequently, articles related to machine learning models, optimization algorithms, and smart control systems, along with their applications in building energy management were reviewed to outline their potential contributions to reducing energy use, lowering carbon emissions, and improving thermal comfort for occupants. Furthermore, research gaps in the use of these smart strategies in residential hydrogen heating systems were thoroughly identified and discussed. The presented findings indicate that the semi-decentralized hydrogen-based heating systems hold significant potential. First, these systems can control the thermal demand of neighboring homes through local substations; second, they can reduce reliance on power and gas grids. Furthermore, the model predictive control and reinforcement learning approaches outperform other control systems ensuring energy comfort and cost-effective energy bills for residential buildings.<br/
Soft stereolithographic 3D printed phantoms for dual-modality particle image velocimetry (PIV)
Get PDFThe fabrication of arterial flow phantoms for fluid dynamics studies suitable for particle image velocimetry (PIV) techniques has presented challenges. Current 3D-printed blood flow phantoms with suitable transparency for optical PIV (laserPIV) are restricted to rigid materials far from those of arterial properties. Conversely, while soft 3D-printed phantoms demonstrate promise for sufficient acoustical transparency for ultrasound PIV (echoPIV), their optical translucency presents challenges for laserPIV applicability. This dual-modality approach leverages the high spatial resolution of laserPIV for in-vitro applications and the ability of echoPIV to quantify flow in both in-vivo and in-vitro application (also inside stents), providing a more comprehensive understanding of flow dynamics. In this study, we present a series of coated thin-walled 3D-printed compliant phantoms suitable for dual-modality PIV flow imaging (i.e., laserPIV and echoPIV) methods, overcoming current 3D-printable material limitations. Stereolithographic (SLA) 3D printing was used to fabricate pipe flow phantoms from a set of commercial soft resins (flexible and elastic) as vascular tissue surrogates. To overcome low transparency and poor surface finish of soft resins, we coated the 3D-printed flow phantoms with a soft, optically transparent, photo-activated polymeric coating. The feasibility of performing dual-modality PIV was tested in an in-vitro flow setup. Our results show that the average normalized root mean square errors obtained from comparing laserPIV and echoPIV velocity profiles against the analytical solutions were 3.2% and 5.1%, and 3.3% and 5.3% for the flexible and elastic phantoms, respectively. These results indicate that dual-modality PIV flow imaging is feasible in the 3D-printed coated phantoms, promoting its future use in fabricating clinically-relevant flow phantoms.</p
Considerations to forgo systemic treatment in patients with advanced esophageal or gastric cancer: A real‐world evidence study
Get PDFThe majority of patients with advanced esophageal or gastric cancer do not start palliative systemic treatment. To gain insight into the considerations underlying the decision not to start systemic treatment, we analyzed characteristics of patients starting and not starting systemic treatment, reasons for not starting systemic treatment, and receipt of local palliative treatments on a nationwide scale. Patients diagnosed with advanced esophageal or gastric cancer between 2015 and 2021 were included (n = 10,948). Survival was compared using propensity score matching on patient and disease characteristics. Most patients did not start systemic treatment (esophageal cancer 59%; gastric cancer 64%). These patients were generally older, more often female, had more comorbidities and a worse performance status. The main reason for not starting systemic treatment was patient or family preference (35%). Among patients who did not start systemic treatment, 47% (esophageal) and 19% (gastric), received local palliative treatment, most commonly radiotherapy. Patients who did not start systemic treatment had worse median overall survival compared to patients who did start (esophageal cancer 2.9 months vs. 8.9 months; gastric cancer 2.2 vs. 8.2 months). These findings indicate that patient condition and disease burden are important aspects in systemic treatment decisions. However, patient or family preference was the main reason for not starting systemic treatment, highlighting that their priorities also strongly influence the decision. Systemic treatment did show to be associated with improved overall survival in matched patients, and therefore adequately weighing treatment risks and benefits based on real world data against patient preferences is of utmost importance
Covalent On-Cell Conjugation of Biomaterials Through Oxidative Phenolic Coupling Regulates Stem Cell Fate via Intracellular Biophysical Programming
Get PDFMechanotransduction is widely used to guide cell fate in hydrogels. Traditionally, hydrogels contain adhesive ligands that dynamically bond with cells to stimulate biochemical signaling axes such as YAP-TAZ. However, the molecular toolbox to achieve mechanotransduction remains virtually limited to non-covalent bonds, which limits the ability to program engineered living matter. Here, it is demonstrated that on-cell chemistry can be leveraged to covalently tether biomaterials directly onto cells, that reveal mechanotransduction via intracellular biophysical programming. Specifically, droplet microfluidics is used to produce single-cell microgels in which individual stem cells are covalently tethered to either soft or stiff hydrogels via on-cell oxidative phenolic coupling. Investigation of mechanotransduction effects at single-cell resolution reveals altered intracellular molecular crowding, calcium signaling, and chromatin organization by regulating cytoplasmic and nuclear volume in a stiffness-dependent yet YAP/TAZ-independent manner. Notably, the addition of conventional dynamic adhesive ligands such as RGDs decreases the chondrogenic commitment of stem cells indicating that covalent cell-material tethering is both efficient and sufficient for programming cell fate. Hence, encoding biomaterials onto cells using covalent on-cell chemistry to attain mechanotransduction expands the ability to guide cellular behavior, which can accelerate the development of in vitro drug-screening models, biofabrication of lab-grown meat, and engineered tissues.</p
Estimating elements susceptible to urban flooding using multisource data and machine learning
Get PDFThe accuracy of flood susceptibility prediction (FSP) could be affected by inadequate representation of flood conditioning factors (FCFs) and the approaches used to identify the most relevant FCFs. This study analyzed twenty-eight FCFs derived from open-access earth observation datasets to develop FSP model for a highly urbanized Akaki catchment, which hosts and surrounds the capital city of Ethiopia, Addis Ababa. In the study, relevant FCFs were first identified using different collinearity-based and model-integrated feature selection methods, and sequentially introduced into a machine learning model. Simulated FSPs were compared against a reference flood inventory dataset to determine the most effective selection method. Findings show that: (i) using extreme rainfall indices improved the accuracy of FSP, (ii) Mean Decrease Impurity (MDI) was found to be the most effective feature selection method, (iii) geomorphological and physiographic FCFs showed the highest and the lowest predictive power, respectively, and (iv) the quantile method outperformed other approaches in classifying the flood susceptibility map. Findings indicate that an area of 217 km2, 43000 buildings, 163 km of paved roads and 0.54 million inhabitants are highly susceptible to flooding in the catchment. In particular, Addis Ababa contains almost 75 % of the estimated susceptible elements in only one-third of the catchment area. The results of this study provide valuable insights for urban planning and flood management, helping to reduce the socio-economic impacts of flooding and enhance urban resilience.</p
Energy storage performance of silicon-integrated Sr<sub>0.98</sub>Mn<sub>0.02</sub>TiO<sub>3</sub> thin film capacitors
Get PDFEpitaxial Sr0.98Mn0.02TiO3 (SMTO) thin films were grown on conductive-oxide electrodes (LaNiO3 – LNO, SrRuO3 – SRO, and La0.67Sr0.33MnO3 – LSMO) buffered SrTiO3/Si substrates, using a pulsed laser deposition method. The effect of the bottom electrodes on the breakdown and energy storage density of SMTO thin films have been systematically investigated. A high recoverable energy storage density (Ur) of 113.3 J/cm3 was achieved at 7.30 MV/cm in an SMTO/LSMO film, which is significantly higher than that of SMTO/SRO (100.4 J/cm3 at 7.15 MV/cm), and SMTO/LNO (67.2 J/cm3 at 6.30 MV/cm) films. This high Ur value is simultaneously attributed to an improvement in both polarization and breakdown strength induced by a high Schottky barrier height at the SMTO/LSMO junction. In addition, the SMTO/LSMO film demonstrated excellent thermal stability (up to 200 °C), and good fatigue endurance (up to 1010 cycles), indicating its suitability for long-term operation and use in harsh environmental conditions of high energy storage capacitor applications.</p
Human cortical high-gamma power scales with movement rate in healthy participants and stroke survivors
Get PDFAbstract: Motor cortical high-gamma oscillations (60–90 Hz) occur at movement onset and are spatially focused over the contralateral primary motor cortex. Although high-gamma oscillations are widely recognized for their significance in human motor control, their precise function on a cortical level remains elusive. Importantly, their relevance in human stroke pathophysiology is unknown. Because motor deficits are fundamental determinants of symptom burden after stroke, understanding the neurophysiological processes of motor coding could be an important step in improving stroke rehabilitation. We recorded magnetoencephalography data during a thumb movement rate task in 14 chronic stroke survivors, 15 age-matched control participants and 29 healthy young participants. Motor cortical high-gamma oscillations showed a strong relation with movement rate as trials with higher movement rate were associated with greater high-gamma power. Although stroke survivors showed reduced cortical high-gamma power, this reduction primarily reflected the scaling of high-gamma power with movement rate, yet after matching movement rate in stroke survivors and age-matched controls, the reduction of high-gamma power exceeded the effect of their decreased movement rate alone. Even though motor skill acquisition was evident in all three groups, it was not linked to high-gamma power. Our study quantifies high-gamma oscillations after stroke, revealing a reduction in movement-related high-gamma power. Moreover, we provide strong evidence for a pivotal role of motor cortical high-gamma oscillations in encoding movement rate. (Figure presented.). Key points: Neural oscillations in the high-gamma frequency range (60–90 Hz) emerge in the human motor cortex during movement. The precise function of these oscillations in motor control remains unclear, and they have never been characterized in stroke survivors. In a magnetoencephalography study, we demonstrate that high-gamma oscillations in motor cortical areas scale with movement rate, and we further explore their temporal and spatial characteristics. Stroke survivors exhibit lower high-gamma power during movement than age-matched control participants, even after matching for movement rate. The results contribute to the understanding of the role of high-gamma oscillations in motor control and have important implications for neuromodulation in stroke rehabilitation.</p
Tsunami boulder transport in coastal environments:insights from physical experiments and dimensional analysis
Get PDFCoastal boulder deposits hold the potential to aid in the reconstruction of past extreme wave events. However, commonly used hydrodynamic equations for calculating wave heights from transported boulders can be inaccurate. New and alternative methods need to be explored in an interdisciplinary way to ensure a more complete picture of the phenomenon of boulder transport is achieved. Through the use of a physical experiment, this study aims to investigate the influence of different tsunami wave types, wave parameters and boulder shapes on boulder transport distance. The experimental results also allow for a novel application of dimensional analysis to enable comparisons with other experiments as well as a field case study. In the experiment an elongate irregularly shaped boulder showed transport distances up to 1 m farther than a cuboid shaped boulder under the influence of the same waves. The irregularly shaped boulder had a predominant transport mode of rolling, whereas the cuboid shaped boulder predominantly underwent sliding transport. Tsunami wave type also influenced boulder transport distances, with N-waves frequently showing greater transport than E-waves of a comparable wave steepness. Key offshore wave and boulder parameters were then compared through dimensional analysis using Buckingham's Pi Theorem, enabling comparisons to other datasets to be made. Data from another published experimental study and a field study in Settai, Japan, showed reasonable agreement, particularly for the shorter period field data. These findings emphasize the importance of incorporating boulder shape, wave type, and dimensional analysis into future studies, providing a foundation for more accurate reconstructions of past tsunami events.</p
IHEART2U:Empowerment Based Design of Social Support Mobile App Development for Autistic Children Caregivers
Get PDFAutism spectrum disorder (ASD) is a neural developmental disorder characterized by impaired social interaction, communication difficulties, and restricted behaviours. Understanding the disorder and providing necessary social support for guidance and assistance is vital for caregivers, including educators, parents, and the public. The aim of this research is to design and develop a social support mobile app for autistic children’s caregivers named IHEART2U. We design the app by incorporating the empowerment-based design elements to ensure it provides practical assistance but also foster a sense of empowerment and control over their child's development and well-being. Caregivers can feel more confident, informed, and supported in their role. For the design and development, we used the Mobile Development Life Cycle (MADLC) as the methodological approach. During the requirements gathering, we conducted interviews in collaboration with the National Autism Society of Malaysia (NASOM), a private school for children with autism and caretakers. Through thematic analysis, we incorporate four empowerment-based design elements: information support, emotional support, companion, customization, and personalization in the user interface (UI) design of the mobile app. Upon completion of the high-fidelity prototype, we conducted usability testing using the System Usability Scale (SUS) to obtain feedback from the stakeholders. The score was 90.83 above average. The respondents provide constructive feedback on how to improve the app. In conclusion, we believe that by integrating these empowerment design elements, the IHEART2U social support mobile app becomes a source of empowerment, support, and guidance tool for caregivers, helping them navigate the challenges of raising and caring for children with autism. Future work will involve iterative user testing and feedback to further refine and enhance the app's effectiveness.</p