Spatial Requirements Research Articles

Overcoming the Challenges of Hyperpolarizing Substrates with Parahydrogen-Induced Polarization in an MRI System.

Hyperpolarization of 13C nuclei in biomolecules and their administration as imaging agents enables in-vivo monitoring of metabolism. This approach has demonstrated potential for deriving imaging biomarkers for cancer detection, differentiation, and therapy efficacy assessment. The in situ generation of polarized substrates using a permanent addition of parahydrogen to an unsaturated precursor inside the bore of an MRI system used for subsequent imaging circumvents the need for a dedicated external polarizer. This approach reduces polarization loss associated with sample transfer, minimizes hardware requirements and cost, and results in reduced spatial requirements. However, performing INEPT-like pulsed sequences for heteronuclear spin-order transfer in the bore of an MRI system is challenged by poor uniformity of static and excitation magnetic field and molecular convection during the polarization transfer. Therefore, here we characterize these effects, implement a robust modification to the pulse sequence, and measure experimentally the polarization improvement upon modification of the sequence. After rigorous optimization of the parameters, we obtained a 13C polarization of 44.5 % for 50 mM of the 1-13C site of ethyl acetate-d6. Our parahydrogen-induced polarization approach enhances the accessibility to hyperpolarized MRI, circumventing the need for an external polarizer.

An innovative hollow-cable dome structure for indoor cooling

In the context of achieving low-carbon and environmentally friendly building solutions, structural design and internal comfort are equally critical considerations for modern buildings. To meet the spatial requirements of long-span structures and ensure internal comfort, this paper proposes an innovative hollow-cable dome structure. By substituting conventional cables with flexible pipes, the structure utilizes the continuous characteristic of cables to create a continuous internal volume. This design allows the hollow-cable dome to function as an air conditioning system, circulating cold air internally to adjust the indoor temperature. This paper first introduces a heat-fluid analysis framework for the hollow-cable dome. And then to verify the feasibility and practicality of the structure and its dual functions, simulations of the heat transfer and indoor cooling process are conducted using commercial software. The proposed structure efficiently realizes dual functions of structural support and temperature regulation, highlighting its promising potential for applications in both structural engineering and indoor environmental quality management. Additionally, the paper investigates the key factors affecting cooling efficiency, focusing on component parameters, structural complexity, and configuration. The comparative analysis reveals that component parameters and structural configuration are closely linked to the indoor cooling effect and temperature distribution. A larger outlet area results in greater cooling efficiency, while increased structural complexity promotes more uniform temperature changes, effectively minimizing hot and cold concentration zones. Therefore, the study provides a theoretical foundation for optimizing the design of the hollow-cable dome structure to enhance cooling performance. Future designs can leverage these insights to achieve better functionality and efficiency, further promoting environmentally friendly and sustainable building practices.

Incorporating tiny forests in the neighbourhood of Singapore - Opportunities and challenges

‘Tiny forests’ have gained traction across the globe as a promising solution for restoring natural ecosystems and enriching biodiversity in highly urbanized areas. In land scarce cities, planting forests could mitigate the impacts of climate change and other urban socio-ecological challenges. This article investigates the potential for tiny forests to be part of the greening strategy in Singapore – a compact city that is already championing greening initiatives. Using a case study of the Jurong West neighbourhood, we conducted a survey aiming to understand people's perceptions and use of urban nature. We complement these results with a rapid assessment of land availability confirming the feasibility of implementing tiny forests in Singapore. From the survey, we found that residents were receptive to the idea of having nature closer to their residential areas despite highlighting disadvantages such as undesirable insects and animals. Factors such as minimal spatial requirements and planting methods that enhance trees growth make tiny forest a useful part of the landscaping portfolio to achieve national greening principles. Overall, we find that tiny forests have the potential to become part of the city-state's greening strategies.

Electron cyclotron emission quasi-optical transmission system on the HL-3 tokamak.

A new quasi-optical (QO) Electron Cyclotron Emission (ECE) transmission system has been established on the HL-3 tokamak, which includes a focusing QO mirror combination and a long-distance transmission line. This system was developed to meet the requirements for poloidal spatial resolution and the high signal-to-noise ratio needed for magnetohydrodynamic (MHD) instability studies using ECE on the HL-3. The QO mirror combination was installed inside the vacuum chamber for focusing. Laboratory test results, theoretical calculations, and synthetic ECE simulation results indicate that the Gaussian beam can meet the spatial resolution requirements for the accurate measurement of the MHD instability on the q = 1/2/3 surfaces, corresponding to the poloidal mode numbers m = 3/6/9. This includes good diagnostic poloidal spatial resolution for the important 2/1 and 3/2 modes. At the front end of the transmission line, a high-efficiency mode converter was designed to transition the TE10 mode to the HE11 mode for input into the transmission line, with an insertion loss of less than 1.5 dB. A 30m long-distance corrugated oversized waveguide was constructed, with transmission losses ranging from 6 to 10 dB in the 60-120GHz range. Polarization adjustment results show that the polarization offset and geometric spatial polarization angle change consistently, which can provide a reference for polarization adjustment in other complex structured transmission lines. The newly established ECE QO transmission system will provide strong support for future physics research involving ECE on the HL-3.

A Review of Intelligent Depth Distance Perception Research for Power Transmission Line Corridor Scenarios

Transmission lines are essential carriers for the transmission of electrical energy, and their safe operation is fundamental to ensuring reliable power supply. However, the environment of transmission line corridors is complex and variable, posing numerous risks of external damage. With the development of smart power systems, information technologies such as video monitoring provide effective means for monitoring and managing external damage to transmission lines. Nonetheless, the current technology for identifying external damage and safe distances for transmission lines is weak, leading to frequent false alarms and low efficiency in practical applications. To address this issue, this paper systematically reviews and summarizes the progress of distance recognition technology in power systems. First, it outlines the spatial distance perception performance requirements for models in transmission line corridor scenarios and summarizes the spatial distance data characteristics of these corridors. Second, the paper categorizes existing common safety distance recognition methods from the perspectives of active and passive ranging, analyzing their advantages and disadvantages in the context of transmission line corridors. Finally, this paper summarizes the types and performance characteristics of current deep learning-based distance recognition methods and proposes a potential application framework for these methods in transmission line corridor scenarios. It also discusses the future application prospects and challenges faced by this framework.

A novel numerical simulation approach for cryogenic CO2 frosting in binary mixture gas by integrating desublimation and gas-solid phase equilibrium models

Cryogenic CO2 separation from natural gas is a promising technology due to its environmental benefits and smaller spatial requirement. Nonetheless, the dynamics of CO2 desublimation and subsequent frost layer formation under cryogenic conditions for natural gas pre-treatment remain largely unexplored. Addressing this gap, this paper presents a novel numerical simulation approach by integrating desublimation phase change model and vapor-solid phase equilibrium model to investigate CO2 frost layer formation on the cold wall, revealing that both the cold wall temperature and the initial CO2 concentration significantly influence the thickness of the CO2 frost layer. Moreover, the study finds that the density of frost layer intensifies over time, with the highest density observed near the cold surface. Furthermore, increasing the cold wall temperature and the flow rate not only increases the average density of the CO2 frost layer but also affects the outlet CO2 concentration. To adhere to specific outlet CO2 concentration targets and desublimation duration, it is critical to adjust the cold wall temperature and the inlet flow velocity dynamically. Therefore, cryogenic CO2 removal methods, by reducing the spatial requirements of CO2 pre-treatment units, offer a practical and efficient solution for small-scale natural gas liquefaction plants. This approach not only facilitates operational efficiency but also contributes to the broader effort of mitigating greenhouse gas emissions, aligning with environmental sustainability objectives.

Effect of Spatial Resolution on Accurate Detection and Localization of Arrhythmia Rotors in Human Right Ventricular Tachycardia.

The goal of this study was to identify the spatial resolution requirements for accurate rotor detection and localization in human right ventricular tachyarrhythmias. Poor spatial resolution is often cited as a reason for the inaccuracy of cardiac mapping catheters in detecting and localizing arrhythmia rotors. High-resolution (0.7 mm) arrhythmia data from optical recordings obtained from human donor hearts (n = 12) were uniformly downsampled to lower resolutions (1.4-7 mm) to approximate the spatial resolution (4 mm) of clinical mapping catheters. Rotors were tracked at various subresolutions and compared to the rotors in the original data by computing F1-scores to create accuracy profiles for both rotor detection and localization. Further comparisons were made according to arrhythmia type, donor sex, anatomical region, and mapped surface: endocardium or epicardium. For a spatial resolution of 4.2 mm, the accuracies of rotor detection and localization were 57% ± 4% and 61% ± 7%, respectively. Arrhythmia type affected the accuracy of rotor detection (monomorphic ventricular tachycardia, 58% ± 4%; ventricular fibrillation, 56% ± 8%) and localization (monomorphic ventricular tachycardia, 70% ± 4%; ventricular fibrillation, 54% ± 13%). However, donor sex, anatomical region (right ventricular outflow tract, mid, and apical), and mapped surface (epicardium and endocardium) did not significantly affect rotor detection or localization accuracy. To achieve rotor detection accuracy of 80%, a spatial resolution of 1.4 mm or better is needed. The accuracy profiles provided here serve as a guideline for future mapping device development.

Automatic Planning Method of Construction Schedule under Multi-Dimensional Spatial Resource Constraints

To enhance the application of building information modeling (BIM) in schedule management for engineering projects, improve spatial planning capabilities, and minimize subjective factors in schedule preparation, this paper presents a framework and method for automatic construction schedule planning based on BIM and data-driven approaches under multi-dimensional spatial resource constraints. The method includes data acquisition, construction process reasoning, time parameter calculation, and schedule generation and scheduling. Initially, the construction data from the BIM model and manual input are imported into the reasoning system to establish the logical relationships of the construction process. Construction time parameters and spatial resource requirements are then automatically calculated using MySQL. Subsequently, the spatial layout and resource allocation data exported from the BIM model are compared to assess whether the space meets the project requirements. Finally, a construction schedule that satisfies the space constraints is generated. The method was validated through a case study, demonstrating its effectiveness in automatic schedule planning under human-computer interaction. This study introduces an innovative approach that considers spatial conflicts in the automatic scheduling process, improving planning efficiency and reducing the risk of spatial conflicts on construction sites.

Imaging Locally Inhomogeneous Properties of Metal Halide Perovskites.

Metal halide perovskites (MHPs) are a perfect example of state-of-the-art photovoltaic materials whose compositional and structural diversity,coupled with utilization of low-temperature processing, can undesirably result in spatially inhomogeneous properties that locally vary within the material. This complexity of MHPs requires sensitive imaging characterization methods at the microscopic level to gauge the impact of such inhomogeneities on device performance and to formulate mitigation strategies. This review consolidates properties of MHPs that are susceptible to local variations and highlights appropriate imaging techniques that can be employed to map them. Inhomogeneities in morphology, emission, electrical response, and chemical composition of MHP thin films are specifically considered, and possible microscopic techniques for their visualization are reviewed. For each type of microscopy, a short discussion about spatial resolution, sample requirements, advantages, and limitations is provided, thus leaving the reader with a guide of available imaging characterization tools to evaluate inhomogeneities of their MHPs.

A spatial data model of blind outdoor navigation for path optimization

Current navigational aids for blind people do not provide spatial information that meets the requirements of blind and visually impaired people (BVIP) for travel, and traditional map-based navigation services cannot be used directly for navigation. The purpose of this paper is to establish a spatial data model that aligns with their outdoor travel requirements to assist them in accessing spatial information. In alignment with the analysis of spatial information requirements for blind people during outdoor travel, the proposed data model divides the outdoor space into the path layer, the functional layer, the obstacle layer, and the transport and weather layer. Areas such as schools and sports fields, which fulfill certain requirements for them, are categorized as functional features. Essential public transportation stations for outdoor travel are included in transport station features, while obstacles that pose threats to their safety constitute obstacle features. Various features in space are spatially connected through different paths. The proposed semantic information properties enhance the information content representation of the features. The geometry of the features and the topological relationships between them are recorded and used for path planning and navigation in combination with the path layer. Finally, the eastern campus of Jiangxi University of Science and Technology served as an experimental area for the development of a prototype system based on the data model, and a case analysis was provided.

The Psychological Impact of Biophilic Design: The Case of Taman Literasi Martha Christina Tiahahu, Jakarta

Abstract The built environment has a profound effect on its users, both psychologically and physiologically. These effects must be taken into consideration within the designers’ thinking process to achieve a resulting design that will not only accommodate the users’ spatial functional requirements but also provide comfort, specifically in the case of this research, through visual sensory points. One of the many benefits of the biophilic design concept is to shift the human psychological state from negative to positive. This design concept has been profoundly implemented in the Taman Literasi Martha Christina Tiahahu, Jakarta. This study uses Taman Literasi Martha Tiahahu (Martha Tiahahu Literary Park) as its object with the purpose of investigating the psychological effect of the Biophilic design concept on the park’s observers through physiological evidence. The study uses the latest biophilic theory of the 14 Biophilic Patterns by William Browning (2014) to identify the biophilic elements found in the park. These elements are documented and matched with which of the 14 patterns mentioned in the theory. This study uses 30 participants to partake in the study, in which their psychological conditions are measured by filling out questionnaires. Their physiological conditions, through blood pressure and heart rate, are measured. The results of this study work in favour of the emotional state shift from negative to positive on its users when experiencing the biophilic spaces.

Dune Hares: Population Indices, Home Range Size, and Habitat Selection of the European Hare on a Danish Island.

Population indices, such as transect counts of animals, can provide important information concerning population changes over time. Moreover, data concerning the home range size and habitat selection of individuals can provide valuable insight into spatial requirements of animals and how they can adapt to variable environments. Here, we describe the population development of European hares (Lepus europaeus) and investigated home range sizes and habitat selection of six radio-tagged individuals on the small (80 ha) Danish Wadden Sea island Langli. The average minimum hare population density from 1983 to 1997 was 64 ± 36 (mean ± SD) hares/km2, with hare numbers varying among years and seasons. The average home range size was 23.3 (CI: 18.9-28.7) ha, which is comparable to agricultural areas of high structural diversity. Moreover, hare habitat selection was generally bimodal, with hares moving over larger areas and selecting marsh habitat for foraging during nighttime, and dune and grassland habitat for resting during daytime, especially during winter. Combined, our results indicate that hare abundance and space use in the dunal landscape of Langli Island were similar to agricultural areas of comparatively high habitat quality. Thus, dunal marsh landscapes offer high-quality habitat for hares and might be of importance as population strongholds at a time when hare populations are declining in many agricultural areas across Europe.

Advanced Beam Estimation for Antennas Via Patterned Coupling-Line Detection Board in Ka-Band

In this research, we present an innovative method for estimating the beams of array antennas. Traditional beam analysis methods rely on placing receiving antennas in the far-field region, which requires moving or rotating the Tx or Rx, and using radiation pattern measurements. However, such methods often demand vast spatial requirements and the use of high-cost network analyzers. In contrast, the technique proposed in this study utilizes a board patterned with coupling lines strategically placed in the antenna's near-field zone. Signals intercepted by these coupling lines undergo conversion into DC voltage via a power detector situated at the line terminus. Interestingly, this method enables beam estimation solely based on the DC voltage level output of the power detector, thus offering a cost-effective and space-efficient solution that represents a significant advancement from traditional beam estimation methods.

Where to fly? Landscape influences on the movement and spatial ecology of a threatened apex predator

Effectively managing apex predators in human-modified landscapes poses considerable challenges. Habitat fragmentation disperses resources across wider expanses and undermines the ability of apex predators to reach isolated habitat patches as they traverse multi-tenured landscapes comprising unsuitable habitat. Understanding a species response to landscape configuration is key to informing effective management strategies, particularly for threatened, mobile and ecologically important species like apex predators. Here we use GPS tracking data collected from 37 powerful owls (Ninox strenua), an Australian threatened apex predator that occurs across the urban-agricultural-forest gradient, to investigate how landscape characteristics influence their spatial and movement behaviour. We demonstrate that as habitat fragmentation increases, the spatial requirements of powerful owls expand, their home-range shape becomes more intricate and individuals travel further each night, significantly adjusting their movement behaviours and spatial configurations to connect remaining habitat. Landscapes with unified and connected habitats, on the other hand, have smaller spatial requirements, likely due to greater habitat availability that minimises competition for essential resources. This facilitates the establishment of smaller home-ranges and consequently, the occurrence of more territories. Interestingly, landscape characteristics did not influence sequential nightly visitation behaviour, suggesting that powerful owls across all landscape types visit different portions of their home-range each night to exert an unpredictable hunting strategy regardless of local landscape conditions. Our research highlights the importance of integrating the influence of local landscape features and visitation behaviours into decision-making processes. This integration is crucial for informing effective conservation strategies aimed at supporting apex predator survival in disturbed landscapes.

Factors shaping home ranges of Eurasian lynx (Lynx lynx) in the Western Carpathians

Understanding how large carnivores utilize space is crucial for management planning in human-dominated landscape and enhances the accuracy of population size estimates. However, Eurasian lynx display a large inter-population variation in the size of home ranges across their European range which makes extrapolation to broader areas of a species distribution problematic. This study evaluates variations in home range size for 35 Eurasian lynx in the Western Carpathians during 2011–2022 based on GPS telemetry and explains how intrinsic and environmental factors shape lynx spatial behaviour when facing anthropogenic pressure. The average annual home range size of lynx ranged from 283 (± 42 SE) to 360 (± 60 SE) km2 for males and from 148 (± 50 SE) to 190 (± 70 SE) km2 for females, depending on home range estimator (95% MCP, KDE and AKDE). Females with kittens had smaller annual and summer home ranges compared to non-reproducing females and subadults had smaller home ranges compared to adults. Lynx home range size was explained by availability of roe deer, except for summer, when alternative prey was likely available. We also found clear evidence of human-induced changes in lynx home range size, in particular, forest cover significantly decreased the home range size of male lynx during summer while road density led to an expansion of both annual and summer lynx home ranges. Lynx exhibited consistent fidelity to their home ranges throughout consecutive seasons, showing no seasonal variations. Strong territoriality was observed among competing males maintaining relatively low home range overlaps and considerable distances between centres of activity. The most pronounced tendency for association was observed between males and females, maintaining relatively close proximity year-round. The insights into lynx spatial requirements provided by our study will greatly enhance the accuracy of population size estimates and effectiveness of mitigation measures across the Western Carpathians.

Study on the Improvement of Theoretical and Electric Field Simulation Methods for the Accurate Prediction of FEEP Thruster Performance

In this study, we investigate and propose an improved theoretical method to more accurately predict the performance of a field-emission electric propulsion (FEEP) thruster with its complex configuration. We identify critical flaws in the previous theoretical methods and derive corrected equations. Additionally, we define and implement the overall half angle of the Taylor cone to account for variations in the Taylor cone’s half angle depending on the applied voltage. Next, we also establish an improved method of the electric filed simulation in a three-dimensional domain to accurately predict a trajectory of extracted ions and a resulting spatial beam distribution of the FEEP thruster by incorporating a configuration of the Taylor cone with the estimated overall half angle from the results of the present theoretical method. Through comparison with the experimental measurements, we found that the present improved methods for theoretical and electric field simulations can yield more accurate predictions than those of the previous methods, especially for higher V and Iem regimes, which correspond to the actual operating conditions of the FEEP thruster. Consequently, we anticipate that the proposed methods can enhance the reliability and efficiency of the design process by accurately predicting performance when developing the new FEEP thruster with its non-symmetric complex configuration to match specific thrust or spatial beam requirements.

Design and on-orbit performance evaluation of Ethiopian earth observation satellite multispectral optical imaging payload

The Ethiopian Earth observation micro-satellite was successfully launched into a sun-synchronous orbit equipped with an optical multispectral imaging payload system. This optical multispectral imaging payload camera weighs 1.4 kg with four spectral bands: RGB and NIR, each having a unique spectral range. Furthermore, it has a field of view of 7.4°×0.3°, a relative F-number of 9.8°, and a spectral range of 0.45∼0.9μm. The present article covers the design and on-orbit performance analysis of the ETRSS-1 electro-optical imaging payload system, which is based on the COTS compact and unobscured off-axis three-mirror anastigmatic system for high-resolution imaging. Additionally, selecting an appropriate imaging sensor, optomechanical architecture, and performance characteristics for optical instruments is investigated to evaluate spatial, spectral, and radiometric requirements and the payload’s on-orbit performance and capability.

Simulating the Effects of Ammonia Crossover and Alternative Ligands in Thermally Regenerative Flow Batteries

There is a significant amount of low-temperature heat (< 100 °C) available globally from various sources such as geothermal energy, industrial processes, and thermal power plants. Electrochemical and membrane-based methods for harnessing this heat are becoming of greater interest due to their ability to utilize the low temperature energy sources and because they can be sized modularly to fit the power, energy, and spatial requirements of the application. The all-aqueous thermally regenerative ammonia battery (Cuaq-TRAB) is a leading technology in the waste heat to electrical power production space due to recent results showing operational power densities of 25 mW cm-2 with an estimated thermal energy efficiency of 7%, outperforming most technologies in this space. Previous research on the Cuaq-TRAB has shown that the battery suffers from the crossover of ammonia through the membrane which adversely impacts battery performance.To investigate these impacts, we developed a simple numerical model that simulates discharge curves using one fitting parameter to account for parasitic crossover instead of modeling species transport through the membrane. The model was able to replicate experimental data from Cuaq-TRABs with different membrane materials and for multiple applied current densities with < 5% error for average power and energy capacity. Results showed that there is a 20% loss in Cuaq-TRAB energy capacity due to ammonia crossover when compared to a discharge with no parasitic crossover losses. The model was then extended to demonstrate the impact of different changes to the electrolyte chemistry on the resultant power and energy capacities for Cuaq-TRABs. Using this model, we estimate that if chloride was the ligand for the positive electrolyte instead of bromide, it would decrease the power and energy capacity of the battery by 30%. However, considering that an economic analysis showed that chloride is 80% cheaper than bromide, it may be beneficial to consider the use of chloride ligands in this technology despite its worse electrochemical performance.

Design of Inductive Power Transfer Charging System with Weak Coupling Coefficient

Inductive power transfer (IPT) technology is used in various applications owing to its safety features, robust environmental adaptability, and convenience. In some special applications, the charging pads are required to be as compact as possible to accommodate practical spatial requirements, and even size requirements dictate that the diameter of the charging pad matches the air gap. However, such requirements bring about a decrease in the transmission efficiency, power, and tolerance to misalignment of the system. In this paper, by comparing a double-sided inductor–capacitor–capacitor (LCC), double-sided inductor–capacitor–inductor (LCL), series–series (SS), and inductor–capacitor–capacitor–series (LCC-S) compensation topologies in IPT systems, we identified a double-sided LCC compensation topology that is suitable for weak coupling coefficients. Furthermore, this study modeled and simulated the typical parameters of coreless coils in circular power pads, such as the number of coil layers, turns, wire diameter, and wire spacing, to enhance the mutual inductance of the magnetic coupler during misalignment and long-distance transmission. A wireless charging system with 640 W output power was built, and the experimental results show that a maximum dc-dc efficiency of over 86% is achieved across a 200 mm air gap when the circular power pad with a diameter of 200 mm is well aligned. The experimental results show that using a suitable compensation topology and optimizing the charging pad parameters enables efficient IPT system operation when the coupling coefficient is 0.02.

Experimental parametric study on two-phase spray cooling of HEF 7100 using flat spray nozzles

Spray cooling is an effective method and thus finds many applications, including thermal management and energy production. In this regard, spray cooling with flat sprays is particularly crucial in applications with space constraints, as it efficiently dissipates heat while conforming to limited spatial requirements. Flat sprays ensure a wide yet uniform distribution of coolant, making it ideal for cooling systems in compact and densely packed environments. Motivated by these advantages, in this study, we performed an experimental study on the effect of major flat spray parameters, which are the spray flow rate (160 mL/min), spray upstream pressure (2.5 and 5.0 bars), spray angle (0, 30, and 90°), spray distance (3 and 10 cm), spray temperature (23 and 61 °C) and wall heat flux (10–100 W/cm2), on the two-phase heat transfer performance. According to the results, unlike full cone nozzles, the spray distance enhances heat transfer. While the cooling rate increased with the upstream pressure, the inlet temperature had a deteriorating effect on the heat transfer performance of the system. The results also indicated that the heat transfer rate decreased with the spray angle. The spray angle-induced effect on the system performance diminished with the spray pressure and temperature. The obtained results were used to develop two correlations for single phase and nucleate boiling heat transfer in flat sprays. The findings of this study suggest that flat sprays, with their significantly lower flow rates compared to full spray cone nozzles, effectively meet the requirements for direct thermal management by offering precise control, reduced fluid consumption, and enhanced efficiency.