Transport Method Research Articles

Assembling the Puzzle of Coparsite Polymorphism: Synthesis, Thermal Expansion, and Quantum Magnetism of α- and β-Cu4O2(VO4)Cl.

Two new dimorphic spin-1/2 quantum magnets, α- and β-Cu4O2(VO4)Cl, were synthesized via a chemical vapor transport method that emulates mineral formation in volcanic fumaroles. α-Cu4O2(VO4)Cl (1) is a pure vanadate analogue of the coparsite mineral characterized by [O2Cu4]4+ 1D single rods, whereas β-Cu4O2(VO4)Cl (2) adopts a new structure type with the [O2Cu4]4+ 2D layered topology. The thermal expansions of both 1 and 2 studied by high-temperature single-crystal X-ray diffraction are reported. Using ab initio calculations, we infer the presence of antiferromagnetic Cu1-Cu3 units with strong couplings on the order of 200-400 K forming chains (1) and layers (2). The Cu2 atoms are weakly coupled to such units. Magnetic susceptibility measurements corroborate this scenario by showing deviations from the paramagnetic behavior even at 300 K. Moreover, 1 reveals an antiferromagnetic ordering below TN = 24 K with a weak uncompensated magnetic moment.

Comparison of Jc measurements obtained by magnetisation and transport methods for a GdBCO-Ag bulk

Comparison of Jc measurements obtained by magnetisation and transport methods for a GdBCO-Ag bulk

Temperature-Dependent Raman Scattering and Correlative Investigation of AlN Crystals Prepared Using a Physical Vapor Transport (PVT) Method

Ultrawide bandgap (UWBG) AlN c- and m-face crystals have been prepared using the physical vapor transport (PVT) method and studied penetratively using temperature-dependent (TD) Raman scattering (RS) measurements under both visible (457 nm) and DUV (266 nm) excitations in 80–870 K, plus correlative atomic force microscopy (AFM) and variable-angle (VA) spectroscopic ellipsometry (SE). VASE identified their band gap energy as 6.2 eV, indicating excellent AlN characteristics and revealing Urbach energy levels of about 85 meV. Raman analyses revealed the residual tensile stress. TDRS shows that the E2(high) phonon lifetime decayed gradually in the 80–600 K range. Temperature has the greater influence on the stress of m-face grown AlN crystal. The influence of low temperature on the E2(high) phonon lifetime of m-plane AlN crystal is greater than that of the high-temperature region. By way of the LO-phonon and plasma coupling (LOPC), simulations of A1(LO) modes and carrier concentrations along different faces and depths in AlN crystals are determined. These unique and significant findings provide useful references for the AlN crystal growth and deepen our understanding on the UWBG AlN materials.

An Analysis of 24-Hour Survival Based on Arrival by Atypical Ground Transport Versus Ground Emergency Medical Services

Objectives Studies comparing police, privately owned vehicle (POV), and ground Emergency Medical Services (GEMS) trauma transports reveal mixed results. It remains unclear whether using nonstandard transport methods may be beneficial in the setting of certain injuries. We sought to determine 24-h survival after transport by police or POV when compared to GEMS. Methods We analyzed data from the Trauma Quality Improvement Program datasets from 2020 to 2022 for patients arriving from scene by POV, police, or GEMS. The primary outcome was 24-h survival. Multivariable logistic regression models were used to adjust for confounders. Further stratification was performed by mechanism. We used abbreviated Injury Severity Score (ISS) by body region to assess those with and without penetrating torso trauma. Results Patients arriving by POV had a lower median age than those arriving by GEMS and a higher proportion of pediatric patients. This group exhibited a lower incidence of blunt trauma but a higher incidence of penetrating trauma, along with fewer serious injuries across all body regions. Across all adjusted models, arrival by POV was associated with higher odds of 24-h survival, except for cases of penetrating torso trauma among pediatric patients. Patients arriving by police also had a lower median age but a reduced proportion of pediatric patients. This group showed a higher proportion of penetrating trauma and serious injuries to the thorax and abdomen. Police arrivals with blunt trauma had higher odds of 24-h survival, while those with penetrating trauma had lower odds of 24-h survival, a pattern consistent when stratifying by ISS greater than 15. Conclusions This study highlights a survival advantage for trauma patients transported by POV compared to GEMS. Limitations include a lack of prehospital transport time and intervention data. While police transport showed improved survival for blunt trauma, it was associated with worse outcomes for penetrating trauma. These findings suggest that nontraditional transport methods may be beneficial in certain scenarios. Future research should aim to refine transport protocols, investigate the impact of nontraditional methods on transport time, and better understand the impact of prehospital interventions on patient outcomes.

Comparative analysis of methods of hydrogen transportation by sea transport based on the criterion of specific loading capacity

The paper examines vessel designs and existing vessels for the transportation of hydrogen in its various aggregate states and chemically bound forms. The aim of the study is to determine the optimal method of transporting hydrogen by sea in terms of specific carrying capacity. The objective of the study was to establish the relationship between the size of the transported commercial batch of hydrogen (taking into account its form) and the technical and operational characteristics of the vessel for its transportation in relation to each of the possible methods of storing hydrogen on board. The approach used made it possible to determine the optimal options in terms of specific carrying capacity for the marine transportation of hydrogen on ships with a displacement of 25…80 thousand tons. It was determined that LPG gas carriers and chemical tankers for transporting ammonia and methanol, respectively, are optimal in terms of specific carrying capacity in the displacement range under consideration. Conceptual designs of vessels for transporting hydrogen in “pure” form (compressed or liquefied) have shown insignificant results. An intermediate position is occupied by the method of transporting hydrogen using liquid organic carriers.

A novel high frequency, high bandwidth, three phase Mach-Zehnder optical data link.

In inertial confinement fusion, hydrogen isotopes are fused together under high pressures and temperatures. Typically, the duration of these experiments is incredibly short, on the order of around 60-150ps. Due to the high radiation environment, a detector's signal is typically data linked far distances to a protected location. The diagnostic challenge for fusion reaction history measurements is to measure signals of interest maximizing dynamic range while also maintaining time resolution on the order of 10ps. In this work, we present a new experimental optical data link used to efficiently transport diagnostic signals over great distances to the recording system while not restricting the dynamic range. The concept of a three phase Mach-Zehnder modulator system is introduced as well as a description of the physical prototype. The initial results from testing at the OMEGA facility show that this system is a viable method for signal transportation.

Study Explores Sustainable Solutions for Managing Contaminants in Produced Water

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 221002, “Sustainable Solutions for Contaminant Management in Produced Water,” by Nick Nicholas, Genesis Water Technologies, and Andrea Bautista-Gomez, SPE, UniXporter. The paper has not been peer reviewed. _ The primary objectives of this paper include identifying key challenges in managing produced water, assessing current produced-water treatment practices, identifying areas for improvement, and establishing an approach focusing on innovative sustainable solutions that benefit both the industry and the environment. In the case-studies section of the complete paper, the authors include detailed application case studies from Colombia and India (the latter is included in this synopsis). Key Challenges in Managing Produced Water Produced-water management presents a complex set of challenges that spans environmental, technical, economic, and regulatory areas, often requiring multifaceted treatment solutions. The following primary impediments faced in produced-water management are detailed in the complete paper: - Variability in water composition - High treatment costs - Large flow volumes - Environmental risks - Regulatory compliance - Limited disposal options - Technological limitations - Beneficial reuse obstacles - Climate change considerations Current treatment technologies include physical separation, chemical treatment, membrane filtration, thermal technologies, and biological treatment. Current disposal methods for produced water management in the US are diversified, with 46% of the water being disposed of, 41% reinjected, and 13% recycled. Various disposal and recycling methods, detailed in the complete paper, include deep well injection, surface discharge, evaporation ponds, and reuse and recycling. Transportation and storage methods include pipeline networks, trucking, and storage facilities, while monitoring and compliance methods include water-quality testing and reporting systems. Waste minimization strategies include downhole water separation and various water-shutoff techniques.

Optimizing transport methods to preserve function of self-innervating muscle cells for laryngeal injection.

Recently, our laboratory has discovered a self-innervating population of muscle cells, called motor endplate-expressing cells (MEEs). The cells innately release a wide variety of neurotrophic factors into the microenvironment promoting innervation when used as an injectable treatment. Unlike other stem cells, the therapeutic potential of MEEs is dependent on the cells' ability to maintain phenotypical cell surface proteins in particular motor endplates (MEPs). The goal of this study is to identify transport conditions that preserve MEE viability and self-innervating function. Muscle progenitor cells (MPCs) of adult Yucatan pigs were cultured and induced to generate MEEs. Effects of short-term cryopreservation methods were studied on MPC and MEE stages. A minimally supplemented medium was investigated for suspension-mediated transport, and MEEs were loaded at a constant concentration (1 × 107 cells/mL) into plastic syringes. Samples were subjected to varying temperatures (4, 22, and 37°C) and durations (6, 18, 24, and 48 h), which was followed by statistical analysis of viability. Transport conditions maintaining viability acceptable for cellular therapy were examined for apoptosis rates and expression of desired myogenic, neurotrophic, neuromuscular junction, and angiogenic genes. Cryopreservation proved detrimental to our cell population. However, a minimally supplemented medium, theoretically safe for injection, was identified. Transport temperature and duration impacted cell viability, with warmer temperatures leading to faster death rates prior to the end of the study. Transport conditions did not appear to affect apoptotic rate. Any expression change of desirable genes fell within the acceptable range. Transport state, medium, duration, and temperature must be considered during the transport of injectable muscle cells as they can affect cell viability and expression of integral genes. These described factors are integral in the planning of general cell transport and may prove equally important when the cell population utilized for laryngeal injection is derived from a patient's own initial muscle biopsy.

Moisture Sources and Atmospheric Circulation Patterns for Extreme Rainfall Event Over North China Plain From 29 July to 2 August 2023

AbstractTwo years following the extreme rainfall event in Henan Province in July 2021, North China was struck by another significant rainfall episode in late July and early August 2023 (the “23.7” event). This recent event, surpassed only by the August 1963 deluge in Henan province, precipitated extensive disasters across the Beijing‐Tianjin‐Hebei region (BTH) over the North China Plain. Understanding the mechanisms underlying such extreme precipitation events, including moisture sources and atmospheric circulation patterns, in the context of synoptic‐scale systems is crucial for accurate predictions and effective disaster mitigation in the future. To achieve this, this study utilized a vertically integrated water vapor transport method and a Water Accounting model to investigate the moisture sources and pathways of the “23.7” event. A systematic analysis of circulation patterns was also conducted based on the ERA5 reanalysis. The results showed that the western North Pacific and Indian Ocean contributed 38.1% and 18.6%, respectively, to the extreme rainfall over the BTH region. Additionally, terrestrial moisture sources contributed 16.59%, playing a significant role in the event. The stable and moisture‐laden air was transported to the BTH due to the influence of binary tropical cyclones “Doksuri” and “Khanun,” as well as the western Pacific subtropical high‐pressure system. Convergence and updraft dynamics trigger convective processes modulated by vortices and topography. The findings of this study help to build a deeper understanding of the formation processes and mechanisms behind such heavy rainfall, which provides insights for model predictions of similar high‐impact low‐frequency extreme rainfall events.

Crystal growth, ferromagnetism and electronic structure of van der Waals NbCo1.1Te2

Recent advances in the synthesis of intercalated compounds have opened new avenues for exploring novel magnetic properties. This work focuses on the synthesis of high-quality single crystals of NbCo1.1Te2, achieved through a meticulously optimized chemical vapor transport method that facilitates effective cobalt intercalation into the van der Waals gaps of NbCoTe2. Comprehensive characterizations, including magnetic susceptibility, angle-resolved photoemission spectroscopy (ARPES), and magnetoresistance measurements, revealed pronounced room-temperature ferromagnetism and significant magnetic anisotropy, along with a confirmed metallic nature of NbCo1.1Te2. These findings underscore the transformative effects of cobalt intercalation on the physical properties of NbCo1.1Te2, demonstrating its promising potential for advanced electronic and spintronic applications, and laying the groundwork for future research on related materials.

Accelerated Transfer Learning for Cooperative Transportation Formation Change via SDPA-MAPPO (Scaled Dot Product Attention-Multi-Agent Proximal Policy Optimization)

A method for cooperative transportation, which required formation change in a traveling environment, is gaining interest. Deep reinforcement learning is used in formation changes for multi-robot cases. The MADDPG (Multi-Agent Deep Deterministic Policy Gradient) method is popularly used for recognized environments. On the other hand, re-learning may be required in unrecognized circumstances by using the MADDPG method. Although the development of MADDPG using model-based learning and imitation learning has been applied to reduce learning time, it is unclear how the learning results are transferred when the number of robots changes. For example, in the GASIL-MADDPG (Generative adversarial self-imitation learning and Multi-agent Deep Deterministic Policy Gradient) method, how the results of three robot training can be transferred to the four robots’ neural networks is uncertain. Nowadays, Scaled Dot Product Attention (SDPA) has attracted attention and is highly impactful for its speed and accuracy in natural language processing. When transfer learning is combined with fast computation, the efficiency of edge-level re-learning is improved. This paper proposes a formation change algorithm that allows easy and fast multi-robot knowledge transfer using SDPA combined with MAPPO (Multi-Agent Proximal Policy Optimization), compared to other methods. This algorithm applies SDPA to multi-robot formation learning and performs fast learning by transferring the acquired knowledge of formation changes to a certain number of robots. The proposed algorithm is verified by simulating the robot formation change and was able to achieve dramatic high-speed learning capabilities. The proposed SDPA-MAPPO (Scaled Dot Product Attention-Multi-Agent Proximal Policy Optimization) learned 20.83 times faster than the Deep Dyna-Q method. Furthermore, using transfer learning from a three-robot to five-robot case, the method shows that the learning time can be reduced by about 56.57 percent. A scenario of three-robot to five-robot is chosen based on the number of robots often used in cooperative robots.

Carbon-Free H2 Production from Ammonia Decomposition over 3D-Printed Ni-Alloy Structures Activated with a Ru/Al2O3 Catalyst

Hydrogen, with its high energy density and zero greenhouse gas emissions, is an exceptional energy vector, pivotal for a sustainable energy future. Ammonia, serving as a practical and cost-effective hydrogen carrier, offers a secure method for hydrogen storage and transport. The decomposition of ammonia into hydrogen is a crucial process for producing green hydrogen, enabling its use in applications ranging from clean energy generation to fueling hydrogen-powered vehicles, thereby advancing the transition to a carbon-free energy economy. This study investigates the catalytic performance of various 3D-printed porous supports based on periodic open cellular structures (POCS) and triply periodic minimal surface (TPMS) architecture manufactured from IN625 nickel alloy powder using the laser powder bed fusion (LPBF) technique. The POCS and TPMS, featuring geometries including BCC, Kelvin, and Gyroid, were analyzed for cell size, strut/sheet diameter, porosity, and specific surface area. Pressure drop analyses demonstrated correlations between structural parameters and fluid dynamics, with BCC structures exhibiting lower pressure drops due to their higher porosity and the open channel network. The dip/spin coating method was successfully applied to activate the supports with a commercial Ru/Al2O3 catalyst, achieving uniform coverage crucial for catalytic performance. Among the tested geometries, the Gyroid structure showed superior catalytic activity towards ammonia decomposition, attributed to its efficient mass transfer pathways. This study highlights the importance of structural design in optimizing catalytic processes and suggests the Gyroid structure as a promising candidate for improving reactor efficiency and compactness in hydrogen production systems.

A novel simulation and supervised machine learning-based prediction framework to predict the total transportation and energy costs for single-family households

This paper focuses on predicting the total transportation and energy costs (TTEC) for single-family households. A system boundary consisting of grid-powered electricity (GE) and solar-powered electricity (SE) as energy inputs and transportation vehicles that include Gasoline Vehicles (GV) and Electric Vehicles (EV) as transportation methods for energy outputs is studied. A novel three-stage evaluation framework is proposed to predict the TTEC under varying single-family household parameters. In the first stage, an energy balance simulation model is proposed to estimate the TTEC for an individual household. In the second stage, the simulation model is run several times under varying parameters to develop synthetic data that is used as input for the third stage supervised machine learning (SML) models. In the third stage, numerous SML models are trained and tested to determine the best SML model that enables us to predict the TTEC with high accuracy. This best SML model can be used as a substitute for simulation model, thereby reducing the computation burden of running the simulation model for each new single-family household. A case study of single-family households in Central Texas in the US is used as an application of the framework. The results indicate that regression SML models are best in predicting the total costs with an adjusted R-squared of 99.13% and 98.88% on training and testing datasets, respectively. In addition, the parameter analysis of regression SML models suggests that the house size, number of GVs, number of EVs, EV and GV ownership costs, and solar implementation at households are the most important parameters to predict TTEC for single-family households. Counterintuitively, number of residents, GV and EV mileage, solar system size, battery capacity and peak solar hours are not significant parameters that contribute to TTEC prediction.

Subsweep: Extensions to the sweep method for radiative transfer

We introduce the radiative transfer postprocessing code Subsweep . The code is based on the method of transport sweeps, in which the exact solution to the scattering-less radiative transfer equation is computed in a single pass through the entire computational grid. The radiative transfer module is coupled to radiation chemistry, and chemical compositions as well as temperatures of the cells are evolved according to photon fluxes computed during radiative transfer. Subsweep extends the method of transport sweeps by incorporating sub-timesteps in a hierarchy of partial sweeps of the grid. This alleviates the need for a low, global timestep and as a result Subsweep is able to drastically reduce the amount of computation required for accurate integration of the coupled radiation chemistry equations. We succesfully apply the code to a number of physical tests such as the expansion of HII regions, the formation of shadows behind dense objects, and its behavior in the presence of periodic boundary conditions.

Analyzing the Supply and Demand Dynamics of Urban Green Spaces Across Diverse Transportation Modes: A Case Study of Hefei City’s Built-Up Area

With the increasing demands of urban populations, achieving a balance between the supply and demand in the spatial allocation of urban green park spaces (UGSs) is essential for effective urban planning and improving residents’ quality of life. The study of UGS supply and demand balance has become a research hotspot. However, existing studies of UGS supply and demand balance rarely simultaneously improve the supply side, demand side, and transportation methods that connect the two, nor do they conduct a comprehensive, multi-dimensional supply and demand evaluation. Therefore, this study evaluates the accessibility of UGS within Hefei’s built-up areas, focusing on age-specific demands for UGS and incorporating various travel modes, including walking, cycling, driving, and public transportation. An improved two-step floating-catchment area (2SFCA) method is applied to evaluate the accessibility of UGS in Hefei’s built-up areas. This evaluation combines assessments using the Gini coefficient, Lorenz curve, location entropy, and local spatial autocorrelation analysis, utilizing the ArcGIS 10.8 and GeoDa 2.1 platforms. Together, these methods enable a supply–demand balance analysis of UGSs to identify areas needing improvement and propose corresponding strategies. The research results indicate the following: (1) from a regional perspective, there are significant disparities in the accessibility of UGS within Hefei’s urban center, with the old city showing more imbalance than the new city. Areas with high demand and low supply are primarily concentrated in the old city, which require future improvement; (2) in terms of travel modes, higher-speed travel (such as driving) offers better and more equitable accessibility compared to slower modes (such as walking), highlighting transportation as a critical factor influencing accessibility; (3) regarding population demand, there is an overall balance in the supply of UGS, with local imbalances observed in the needs of residents across different age groups. Due to the high specific demand for UGS among older people and children, the supply and demand levels in these two age groups are more consistent. This study offers valuable insights for achieving the balanced, efficient, and sustainable development of the social benefits of UGS.

Risk Factors for Eye and Orbital Injuries Related to Electric Scooters and Off-Road Vehicles

ABSTRACT Purpose Electric scooters (e-scooters) have rapidly become a mainstream method of transportation in the U.S. but there is consequently limited data on their safety profile. This study evaluates ophthalmic injuries related to e-scooters compared to non-motorized scooters and off-road vehicles (ORV). Methods This retrospective study uses the National Electronic Injury Surveillance System (2014 to 2023). Ocular injury profiles associated with conventional scooters, e-scooters, and off-road vehicles were included. Results E-scooter ocular injuries rose by 1950% between 2014 and 2023. E-scooter riders were 4.3 times more likely to sustain orbital fractures and 2.7 times more likely to be hospitalized than non-motorized scooter riders. ORV and e-scooter riders had comparable injury and hospitalization patterns. Alcohol use and lack of helmet use were significant contributors to injury severity. Conclusions and Relevance Injury patterns and hospitalization rates in e-scooter accidents resemble those of ORV incidents. Findings highlight the need for public health interventions to reduce the burden of e-scooter-related injuries.

Enhancing Urban Livability in Shanghai under Sustainable Development

Abstract: As one of China's largest cities, Shanghai faced significant challenges during its rapid urbanization, including housing supply-demand imbalances, traffic congestion, and environmental pollution. In response to these issues, this paper examined urban sustainability in Shanghai within the framework of the United Nations' Sustainable Development Goal. The Shanghai Municipal Government took proactive steps to improve urban livability by implementing various measures such as increasing the supply of affordable housing, expanding and enhancing public transportation systems, strengthening environmental governance, and improving public safety. These initiatives were specifically designed to address the pressing issues of housing shortages, traffic congestion, and environmental pollution, with the ultimate goal of improving residents' quality of life and enhancing the city's overall attractiveness. Through an extensive literature review and case analysis, this study proposed several additional improvement measures. These included continuing to increase land supply, tightening real estate market regulations, promoting the adoption of green transportation methods, enhancing intelligent traffic management systems, reinforcing environmental supervision and governance, and improving the overall quality of public services. The research offered valuable insights for other cities striving to achieve sustainable development goals, providing practical strategies for further enhancing urban livability and ensuring long-term sustainability..

Effect of Different Doping Concentrations on the Properties of Fe2+:ZnSe and Fe2+, Cr2+:ZnSe Crystals Grown by the Chemical Vapor Transport Method.

The Fe2+:ZnSe crystal is an important material for 3-5 μm mid-infrared lasers. In this work, we have grown different doping concentrations of Fe2+:ZnSe and Fe2+, Cr2+:ZnSe by the chemical vapor transport method. The doped crystals have the same structure. The lattice constant increases slightly with a higher Fe2+ concentration, while the doped Cr2+ has a great influence on the lattice constant. Besides, with a higher Fe2+ concentration, the TO mode has no change and the LO mode presents a small blue shift. The doped ZnSe crystals all have a wide absorption peak in the range of 2.3-4.5 μm, and these absorption peaks widen with the increase of the Fe2+ doping concentration. Besides, in the range of 5-20 μm, the crystals have good transparency. The concentrations of 3, 2, and 1% Fe2+ samples are calculated to be 4.15 × 1019, 3.27 × 1019, and 3.02 × 1019 cm-3, respectively, and the Fe2+ concentration of the Fe2+, Cr2+:ZnSe sample is 3.71 × 1019 cm-3. The band gap decreases from 2.52 to 2.27 eV with a higher Fe2+ doping concentration. Therefore, we can modulate the absorption bandwidth and band gap by doping the ion concentration, which is more suitable for developing mid-infrared gain medium applications.

Ray decomposition radiation transport for high performance computing

Radiation transport is essential in many high-performance computing problems. However, its complexity presents computational challenges. This study presents a novel algorithm, the ray decomposition method for long characteristics transport, designed to address communication challenges specific to distributed memory computing. Reordering of ray property calculations reduces communication cost associated with sequential ray integration. Verification studies demonstrate solution convergence. Performance modeling of the ray decomposition method predicts the compute time from first principles. Consistency of experimentally measured performance with analytical predictions validates the performance scaling model. This work represents a step towards more scalable and efficient radiation transport simulations.

Flow in filopodia: re-organization and the representation of biological entities as computational objects

Actin is the most abundant protein in eukaryotic cells. They form filamentous polymers that are organized in different ways within the cell to perform various functions. For instance, prominent parallel bundles of F-actins mediate the formation and dynamics of filopodia that are long, finger-like protrusions of cell membrane occurring in certain cells, like growing neurons. Understanding actin organization dynamics and its regulation is a crucial problem for biologists that cannot be solved exclusively by biological methods, requiring the support of mathematical and computational modelling. In this work, grounded on a previous hypothesis of ours about the cytosol flow within filopodia, we address several modelling challenges posed by the growth of filopodia in neurons. We use alternative stochastic models and particle-centered numerical methods for transport and elongations, as well as an innovative object-oriented modelling-strategy to represent chemical transformations, polymerization, and their regulation. These modelling strategies allowed for simulating elongations 20 times longer than the typical ranges attained by commonly used filopodia diffusion models, and show that our hypothesis is feasible, acting as a proof-of-concept about the importance of considering organization as a key element in biological explanations.