90 research outputs found
Data for: Preparation, thermal characterization and examination of phase change materials (PCMs) enhanced by carbon-based nanoparticles for solar thermal energy storage
No full textThis data file contains the processed material property data of three nano-enhanced phase change materials, including graphene nanoplatelets (GNPs)/myristic acid (MA), multi-walled carbon nanotubes (MWCNTs)/MA and nano-graphite (NG)/MA composites
A quantitative study of leaf development in the moss Physcomitrium patens
No full textThe diverse shapes and architectures of plant organs are closely linked to their specialized functions. For instance, laminar structures of leaves are optimized for photosynthesis, while the elongated and branching architecture of roots facilitates anchoring and nutrient absorption. The formation of these specialized organ shapes involves a complex interplay of genetic instructions, individual cellular behaviors, and coordinated organ-level processes. Developmental processes such as cell division, growth, differentiation, and patterning are regulated by both local and global cues in a spatiotemporal manner, ultimately shaping the final organ structure. In this PhD thesis, I investigated the development of phyllids, the leaf-like structures of bryophytes, in the model moss species Physcomitrium patens. The current knowledge on moss phyllid development, focusing on cellular resolution and molecular regulation was summarized in Chapter 2. Using a multidisciplinary approach that combined genetics, chemical treatments, time- lapse imaging, and computer modeling, we explored two key aspects of moss phyllid morphogenesis: the role of auxin in regulating developmental gradients (Chapter 3) and the impact of cytokinesis defects on organ formation (Chapter 4). In the first research project (Chapter 3), we show how auxin coordinates spatial-temporal cellular behavior to control phyllid shapes. We tracked phyllid morphogenesis from a single initial cell to maturity, uncovering how auxin shapes developmental gradients. Our findings reveal that auxin spatially inhibits cell divisions and promotes cellular elongation, tuning intrinsic gradients that drive organ development. Interestingly, in contrast to vascular plants, we suggest that PIN proteins in moss may limit basipetal auxin transport by reducing intracellular auxin concentrations. These results suggest that while the role of auxin in development is conserved between mosses and angiosperms, its transport mechanisms have diverged through evolution.The diverse shapes and architectures of plant organs are closely linked to their specialized functions. For instance, laminar structures of leaves are optimized for photosynthesis, while the elongated and branching architecture of roots facilitates anchoring and nutrient absorption. The formation of these specialized organ shapes involves a complex interplay of genetic instructions, individual cellular behaviors, and coordinated organ-level processes. Developmental processes such as cell division, growth, differentiation, and patterning are regulated by both local and global cues in a spatiotemporal manner, ultimately shaping the final organ structure. In this PhD thesis, I investigated the development of phyllids, the leaf-like structures of bryophytes, in the model moss species Physcomitrium patens. The current knowledge on moss phyllid development, focusing on cellular resolution and molecular regulation was summarized in Chapter 2. Using a multidisciplinary approach that combined genetics, chemical treatments, time- lapse imaging, and computer modeling, we explored two key aspects of moss phyllid morphogenesis: the role of auxin in regulating developmental gradients (Chapter 3) and the impact of cytokinesis defects on organ formation (Chapter 4). In the first research project (Chapter 3), we show how auxin coordinates spatial-temporal cellular behavior to control phyllid shapes. We tracked phyllid morphogenesis from a single initial cell to maturity, uncovering how auxin shapes developmental gradients. Our findings reveal that auxin spatially inhibits cell divisions and promotes cellular elongation, tuning intrinsic gradients that drive organ development. Interestingly, in contrast to vascular plants, we suggest that PIN proteins in moss may limit basipetal auxin transport by reducing intracellular auxin concentrations. These results suggest that while the role of auxin in development is conserved between mosses and angiosperms, its transport mechanisms have diverged through evolution
Building performance enhancement using phase change materials and solar photovoltaic thermal systems
No full textDue to the significant and ever-growing energy demand of building heating, ventilation and air conditioning (HVAC) systems, energy consumption in the building sector is continuously increasing. The development and deployment of advanced energy technologies and the improvement in the energy efficiency of building HVAC systems are therefore essential to significantly reduce energy consumption and achieve sustainability in the built environment. Solar photovoltaic thermal (PVT) collectors and thermal energy storage (TES) using phase change materials (PCMs) are among the sustainable and environmentally friendly technologies. The integration of PVT collectors and PCMs into buildings and building HVAC systems could be an alternative solution to rationalise the utilisation of solar energy so as to improve building thermal performance and energy efficiency. Although different solar thermal systems with integrated PCMs have been studied over the last decades, only a few trials have been carried out to simultaneously integrate PVT collectors and PCMs with buildings and building HVAC systems. This thesis presents the development, modelling, experimental investigation, and design optimisation of building and building HVAC systems with PCMs and PVT collectors for improved building performance in terms of effective thermal management and enhanced energy efficiency. Three different approaches have been developed in this study to integrate PCMs and PVT collectors to develop energy efficient buildings and building HVAC systems. These systems are: i) buildings with envelopes enhanced by PCMs (called PCM enhanced buildings) and PVT collectors for space heating; ii) a centralised PCM thermal energy storage (TES) system with integrated PVT collectors for solar heat storage and; iii) an air source heat pump system with integrated PVT collectors and PCM layers laminated into building ceiling for space conditioning
Leaf Morphogenesis: Insights From the Moss Physcomitrium patens
No full textInternational audienceSpecialized photosynthetic organs have appeared several times independently during the evolution of land plants. Phyllids, the leaf-like organs of bryophytes such as mosses or leafy liverworts, display a simple morphology, with a small number of cells and cell types and lack typical vascular tissue which contrasts greatly with flowering plants. Despite this, the leaf structures of these two plant types share many morphological characteristics. In this review, we summarize the current understanding of leaf morphogenesis in the model moss Physcomitrium patens, focusing on the underlying cellular patterns and molecular regulatory mechanisms. We discuss this knowledge in an evolutionary context and identify parallels between moss and flowering plant leaf development. Finally, we propose potential research directions that may help to answer fundamental questions in plant development using moss leaves as a model system
Talking about Problems and Countermeasures of Small-sized Apartments Design
No full textIn order to promote the healthy development for small apartments, the author made a full investigation to Zhengzhou of China, analyzed the existing problems of small-sized houses, and proposed improvement suggestions from traffic space, family-unit design and plan-combination. These measures will help to create a suitable living environment for users
Anti-Disturbance Tracking Control for a Class of PMSM Driven-Based Flexible Manipulator Systems With Input Saturation and Angular Velocity Constraint
No full textThis paper proposes a feasible anti-disturbance constrained control algorithm for a class of typical permanent magnet synchronous motor (PMSM) driven-based single-joint flexible manipulator systems with input saturation and angular velocity constraint. Firstly, by actuating with a surface-mounted PMSM, and setting the d-axis current as zero, the single-joint flexible manipulator is converted into a normal state space model. Secondly, compared with classical harmonic or linear disturbance, the exogenous disturbance model with configurable parameters and the associated disturbance observer (DO) are continuously introduced to dynamically estimate those unknown irregular disturbance. Moreover, by combining the convex hull representation of the saturating input with the suggested adaptive law, an efficient adaptive active anti-disturbance controller is designed to ensure the stability of closed-loop manipulator systems. By using convex optimization technique, not only the dynamic tracking for the rotation position but also the angular velocity constraint can be guaranteed simultaneously. Finally, simulation results for three different kinds of disturbances are showed to demonstrate the superiority of the proposed method
Talking about Problems and Countermeasures of Small-sized Apartments Design
No full textIn order to promote the healthy development for small apartments, the author made a full investigation to Zhengzhou of China, analyzed the existing problems of small-sized houses, and proposed improvement suggestions from traffic space, family-unit design and plan-combination. These measures will help to create a suitable living environment for users
Deep texture-depth-based attention for face recognition on IoT devices
No full textTraditional face recognition systems use RGB images as input for feature extraction and classification. However, conventional methods based on color images experience non-trivial accuracy drop under several challenging conditions like occlusion, pose variation and facial expression changes. With the gradually decreasing cost of smart sensors, RGB-Depth(D) images captured using low-cost sensors are used to provide complementary features to RGB images. Both the extracted Local Binary Pattern (LBP) features and depth map contain additional discriminative information that can guide the face recognition model to focus on the important parts of the input image. In this paper, we propose a novel end-to-end network that combines both texture and depth features for automatic attention-based face recognition. The experiment results demonstrate that the proposed method has improved recognition accuracy under diverse variations. Our proposed face recognition model has been implemented on the NVIDIA Jetson Nano device to evaluate its performance with compact feature extractors used on different branches of the model. The results show that our method can improve the FPS of face recognition on an edge-coming device from 1.6 to 3.8 with <1% accuracy degradation.Ministry of Education (MOE)Submitted/Accepted versionThis research is supported by the Ministry of Education, Singapore, under its AcRF Tier 2 Award No. MOET2EP50220-0003
Performance Enhancement and Life-Cycle Cost Savings of Supercooled Water Ice Slurry Generation Systems Using Heat Regeneration
No full textThis paper presents the development and utilisation of a heat regeneration approach to enhancing the performance and reducing the life-cycle cost of supercooled water ice slurry generation systems. Two supercooled water systems with direct and indirect ice slurry generation were enhanced by the heat regeneration approach to avoid excessive cold loss and increase the supercooling degree, thereby improving system efficiency while reducing operational costs. Their respective performance and life-cycle costs were experimentally evaluated and compared to the ones without heat regeneration enhancement under different working conditions, as well as to a conventional scraped surface ice slurry generator used as a benchmark. It was found from the comparative investigation that the heat regeneration approach can effectively reduce the water temperature at the inlet of the supercooler, allowing a significant amount of cold loss to be saved for ice slurry generation. The effective utilisation rate of cold can be effectively improved by over 15% when using the heat regeneration approach, and the unit ice mass power consumption can be reduced by 12–20%. Due to the attractive energy-saving potential, the operational cost-effectiveness of the enhanced systems contributed to cut-down of life-cycle cost. It was found that the life-cycle costs of the enhanced direct and indirect ice slurry generation systems were 62.0% and 74.7% lower than that of the conventional scraped surface ice slurry generator, respectively
Self-consistent Bogoliubov-de Gennes theory of the vortex lattice state in a two-dimensional strongly type-II superconductor at high magnetic fields
No full textA self-consistent Bogoliubov-de Gennes theory of the vortex lattice state in a 2D strong type-II superconductor at high magnetic fields reveals a novel quantum mixed state around the semiclassical H-c2, characterized by a well-defined Landau-Bloch band structure in the quasiparticle spectrum and suppressed order-parameter amplitude, which sharply crossover into the well-known semiclassical (Helfand-Werthamer) results upon decreasing magnetic field. Application to the 2D superconducting state observed recently on the surface of the topological insulator Sb2Te3 accounts well for the experimental data, revealing a strong type-II superconductor, with unusually low carrier density and very small cyclotron mass, which can be realized only in the strong coupling superconductor limit.E. Bishop and J. Bishop research fund at TechnionSCI(E)ARTICLE29
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