Simple Transport Research Articles

Numerical simulation method of multi-fracture fracturing coupling proppant transport

Hydraulic fracturing is a critical technology for the efficient development of unconventional reservoirs. It involves multi-physics coupling, making its numerical simulation an extremely challenging task. In this paper, an efficient hydraulic fracturing simulator is developed by integrating a simplified proppant transport model into the multi-fracture fracturing framework. In the fracture propagation model, the finite volume method is used to solve fluid flow, while the displacement discontinuity method is employed rock deformation. Proppant transport is realized by the simplified Eulerian–Eulerian method, which only needs to consider the one-dimensional fluid flow. The high-precision weighted essentially non-oscillatory scheme is used to solve the nonlinear proppant transport equation. Compared with the Eulerian–Lagrangian method, the proposed method enhances simulation efficiency by 2–3 orders of magnitude. The numerical model is verified through physical experiments and fracture analytical solutions. The fracture propagation and proppant transport models are implemented via a unidirectional coupling strategy. First, the fully coupled model calculates the fracture morphology, followed by the computation of proppant distribution at each time step. Four cases were established to analyze the effects of fracturing fluid injection time, injection rate, fracture cluster spacing, and the number of fracture clusters on the industrial-scale proppant distribution in fractures. This method can be applied to large-scale fracturing simulation, optimization of fracturing parameters and other fields requiring high computational efficiency.

Transport properties of h-BN lateral devices

One of the well-established and significant applications of hexagonal boron nitride (h-BN) is in solid-state neutron detectors, which necessitate the development of quasi-bulk h-BN crystals. To advance the material and device development of h-BN, it is essential to characterize its bulk electrical transport properties. However, this task is challenging due to h-BN's ultrawide bandgap (UWBG) of approximately 6.1 eV, which results in an extremely high electrical resistivity, typically exceeding 1012 Ω⋅cm. On the other hand, the mobility-lifetime (μτ) product, a key figure of merit for determining the overall device performance, is more readily accessible through the characterization of the I-V characteristics under illumination. In this study, we investigate the in-plane μτ products of lateral devices fabricated from freestanding quasi-bulk h-BN wafers synthesized by hydride vapor phase epitaxy. Our results reveal an unexpected decrease in the in-plane μτ product as the device width decreases. Utilizing a simple two-region carrier transport model, where the central region of the device represents the bulk h-BN material free from metal contacts and the two edge regions are influenced by metal contacts, we demonstrate that the μτ product in the edge areas covered by metal contacts decreases by nearly two orders of magnitude compared to the bulk value. We attribute this significant reduction in μτ product to the layered crystalline structure of h-BN, which permits metal atoms to infiltrate into the interlayer spacings. As a result, the measured μτ product is significantly lower than the true bulk value. These findings provide valuable insights into the design and fabrication of high-performance h-BN devices, which typically leverage its exceptional in-plane transport properties.

Uncovering the potent antimicrobial activity of squaramide based anionophores - chloride transport and membrane disruption.

Antimicrobial resistance (AMR) - often referred to as a silent pandemic, is at present the most serious threat to medicine, and with constantly emerging resistance to novel drugs, combined with the paucity of their development, is likely to worsen. To circumvent this, supramolecular chemists have proposed the applicability of synthetic anion transporters in the fight against AMR. In this article we discuss the synthesis, supramolecular characterisation and biological profiling of six structurally simple squaramide anion transporters. Through a combination of spectroscopic techniques, and cellular assays we have deduced the mode of action of these antimicrobial agents to be as a result of both anion transport and membrane disruption. Furthermore, through the synthesis of two fluorescent analogues we verified this membrane-localised activity using Super-Resolution nanoscopy methods. These compounds represent particularly active antimicrobial anionophores and compliment similar reports showing the applicability of agents such as these in the fight against AMR.

Metabolic Mode of Alginate-Encapsulated Human Mesenchymal Stromal Cells as a Background for Storage at Ambient Temperature.

Introduction: Human mesenchymal stromal cells (MSCs) are attractive for both medical practice and biomedical research. Nonfreezing short-term storage may provide safe and simple transportation and promote the practical use of MSCs. Objectives: We aimed to determine the duration of efficient storage at ambient temperature (22°C) of human dermal MSCs in different three-dimensional organization and to investigate the role of cell metabolic mode in the resistance to the ambient storage damaging factors. Methods: MSCs in monolayer, suspension, and encapsulated in alginate microspheres (AMS) were stored in sealed containers at 22°С in culture medium. Viability (fluorescein diacetate /ethidium bromide) and metabolic activity (Alamar Blue assay) were assessed at 0, 3, 7, 10, and 14 days of the storage. Mitochondrial membrane potential (JC-1 test), cell cycle analysis, reactive oxygen species level, and resistance to hydrogen peroxide were analyzed under culture conditions. Results: Alginate encapsulation was shown to maintain viability (about 85%), metabolic activity, and adhesion ability during storage for 7 days. The storage of MSCs in both monolayer and suspension was less efficient. Culture of MSCs in AMS decreased basal metabolic activity, mitochondrial activity, and led to reversible cell cycle arrest compared to standard two-dimensional culture. MSCs in AMS have a lower basal level of reactive oxygen species and higher resistance to hydrogen peroxide compared with those in monolayer culture. Conclusion: Revealed shift into quiescent metabolic mode is essential for alginate-encapsulated MSCs resistance to storage at ambient temperature.

Mechanical Design and Testing of Mobile Monitoring Units for Security Systems

Mobile monitoring systems are currently used in many applications related to environmental applications or the monitoring of health status. However, security monitoring systems are usually chosen for a specific object, area or perimeter. The main goal of our article is to present the mechanical design of mobile monitoring units. These units create the basis of a developed mobile monitoring security system, which can be applied to monitor any area of interest, even in demanding weather conditions, involving, for example, windiness or wide operational temperature ranges. Therefore, this article is focused on the mechanical design of mobile monitoring units, which are constructed not only so that they can withstand challenging environmental conditions, but also with regard to their simple transportation, manufacturing process and, if necessary, possible repairs. During the design, emphasis was also placed on the vibrations of the mobile monitoring units and their temperature dependence, because vibrations can significantly affect the correct functioning of the mobile monitoring security system and cause false alarm situations. To confirm the correctness of the simulation models, experiments were performed on the mobile monitoring unit prototypes.

Impact of artificial sunlight aging on the respiratory effects of polyethylene terephthalate microplastics through degradation-mediated terephthalic acid release in male mice.

Microplastics are ubiquitous in the atmosphere, leading to human exposure through inhalation. Airborne microplastics undergo degradation due to sunlight irradiation, yet the respiratory risks associated with degraded microplastics remain poorly understood. In this study, we investigated the respiratory effects of polyethylene terephthalate (PET) degraded by artificial sunlight and created a transport and degradation model of PET for risk assessment. PET fibers were cut and subjected to artificial sunlight irradiation. Mice exposed to aged PET showed increased airway resistance induced by methacholine (MCh) inhalation, along with lung inflammation and neutrophil infiltration. Terephthalic acid (TPA) was continuously released from PET aged by artificial sunlight. Exposure to TPA also caused lung inflammation and enhanced airway resistance induced by MCh in mice. These findings indicate that aged PET can cause respiratory impairment via TPA release. A simple transport and degradation model was developed to quantitatively relate the abundance of aged PET produced in this study (i.e. 4,000 × 96 Wm-2h) and aged fractions of PET that can be generated in the atmosphere. Our results suggested 10% to 60% of PET was degraded as that produced in this study over sunny regions in summer, whereas only lower than 1% in high-latitude cities in Europe in winter. This study demonstrates the importance of considering the abundance of aged PET and further development of a transport and degradation model of PET to assess the risk of degraded PET in the atmosphere.

Profile of Traditional Fishermen on the Barito River

Fishermen are residents who do the work of looking for fish to meet their living needs. The fishing gear used is a simple fishing tool that is still traditional, these fishermen are trying to meet their living needs, in an era that is increasingly advanced. These traditional fishermen look for fish in the Barito River. With traditional fishing gear, these river fishermen are trying to find luck in catching fish. These traditional fishermen gain knowledge in going to sea from the teachings of their previous parents. The purpose of this study is to describe the profile of traditional fishermen and their fish catches in the Barito River. Qualitative methods and descriptive approaches used by researchers. This research is located in Anjir Village, Serapat Muara. The instrument for writing this study is the researcher himself and the data collected by the data collection techniques used are observation, interviews and documentation. The subject of this study is fishermen in Anjir Serapat Muara Village. The results of the research are that fishermen in Anjir Serapat Muara village are traditional fishermen both in terms of tools, materials and transportation used. They go to sea because it is done from generation to generation. The catch of this traditional fisherman is still small. Because by using simple fishing gear, the catch of fish is still minimal. The conclusion of this study is that in Anjir Serapat Muara Village, there are people who work as river fishermen who use fishing gear and simple transportation to sea. Fishermen have the knowledge to go to sea to find fish obtained by fishermen from their parents who have been taught since childhood and have been passed on until now to meet their needs.

Atomic-level design of biomimetic iron-sulfur clusters for biocatalysis.

Designing biomimetic materials with high activity and customized biological functions by mimicking the central structure of biomolecules has become an important avenue for the development of medical materials. As an essential electron carrier, the iron-sulfur (Fe-S) clusters have the advantages of simple structure and high electron transport capacity. To rationally design and accurately construct functional materials, it is crucial to clarify the electronic structure and conformational relationships of Fe-S clusters. However, due to the complex catalytic mechanism and synthetic process in vitro, it is hard to reveal the structure-activity relationship of Fe-S clusters accurately. This review introduces the main structural types of Fe-S clusters and their catalytic mechanisms first. Then, several typical structural design strategies of biomimetic Fe-S clusters are systematically introduced. Furthermore, the development of Fe-S clusters in the biocatalytic field is enumerated, including tumor treatment, antibacterial, virus inhibition and plant photoprotection. Finally, the problems and development directions of Fe-S clusters are summarized. This review aims to guide people to accurately understand and regulate the electronic structure of Fe-S at the atomic level, which is of great significance for designing biomimetic materials with specific functions and expanding their applications in biocatalysis.

Advanced optimization of elastic sheets for solar parabolic trough concentrators: integrating particle swarm optimization and genetic algorithms

Abstract The fabrication of solar parabolic trough concentrators using flat elastic sheets presents a straightforward and cost-effective method. This paper introduces an optimization technique centered on stiffness adjustment, harnessing elastic buckling to attain precise parabolic shapes in these concentrators. Through an enhanced Particle Swarm Optimization-Genetic Algorithm (PSO-GA), strategically punched holes are optimized on the flat sheet, allowing for the attainment of perfect parabolic shapes by controlling the chord length with a positional rod or cable. The efficacy of this approach is showcased not only through interactive finite element analysis and ray tracing software simulations but also via experimental sunlight concentration. A geometric concentration ratio of up to 145.16 is achieved, underscoring the effectiveness of this innovative concept. This approach facilitates the simple fabrication and transportation of flat mirror elements to field sites, where they can be assembled into parabolic trough concentrators, offering potential cost reductions and highly efficient solar energy solutions.

Quantifying Lithium-Ion Battery Rate Capacity, Electrode Structuring, and Transport Phenomena Using E-I Measurements

The specific energy of lithium-ion batteries (LIBs) can be enhanced through various approaches, one of which is increasing the proportion of active materials by thickening the electrodes. However, this typically leads to the battery having lower performance at a high cycling rate, a phenomenon commonly known as rate capacity retention. One solution to this is perforating the electrode, by creating channels or corrugations in the active electrode material, either as holes or as channels. This is known to reduce the rate capacity retention effect, but in order to engineer this better, a simplified transport process analysis needs to be established. In this paper, we propose a classic electrochemical analysis based on voltage–charge cycling measurements in order to obtain a classical mass transport coefficient, hm, that is further used as a main indicator for electrode design quality assessment. We also demonstrate theoretically and experimentally how the mass transfer coefficient, hm, can be determined and how it changes as the electrode layer thickness increases, with and without electrode corrugations.

Evaluating the accuracy and reliability of non-piezo portable ultrasound devices in postpartum care.

The early diagnosis of hemorrhage viapostpartum ultrasound is crucial to initiate therapy and, thus, prevent maternal death. In these critical situations rapid availability and simple transport of ultrasound devices is vital, paving the way for a new generation of portable handheld ultrasound devices (PUD) consisting of transducers and tablets or smart phones. However, evidence to confirm the diagnostic accuracyof these new devices is still scarce. The accuracy and reliability of these new devices in relation to established standard ultrasound devices is analyses in this pilot study by comparing diagnoses and by applying statistical analysis via Bland-Altman plots, intraclass correlation coefficients (ICC), and Pearson correlation coefficients (PCC). One hundred patients of a university hospital were included in this study. In all cases, the same diagnosis was made regardless of the applied ultrasound device, confirming high accuracy. There was a high correlation (PCC 0.951) and excellent agreement (ICC 0.974) in the assessment of the cavum, while the assessment of the diameters of the uterus showed only a good correlation and a goodagreement. Subgroup analysis for maternal weight, mode of delivery and day after deliverywasperformed CONCLUSION: Thesame diagnosis independent ofthe used devices and excellent results of the cavum assessment promote the use of PUDs in a clinical setting. The slightly lower accuracy in the measurement of the uterus may be caused by the PUD's small acoustic window, reflecting one of its weaknesses.Therefore, the patient may benefit from the short time to diagnosis and the unbound location of examination, either in the delivery room, on the ward, or at home.

A systemic approach for assessing infrastructure component importance in hazard-prone communities

Investing in pre-event disaster mitigation interventions for physical infrastructure, such as structural retrofits and enhancements, can be costly due to limited resources. To prioritize investments, infrastructure components are ranked by their criticality within the overall system. To be effective in real-world deployment, this approach must account for the complex interactions between components, as failures can occur simultaneously across large geographical areas due to the hazard footprint. As a result, hazard-specific uncertainties and spatial correlations may lead to distinctive failure patterns. In this study, we propose a novel data-driven framework leveraging Monte Carlo simulation, that harnesses the individual realizations to capture and model realistic component damage patterns under a specified hazard scenario. This framework addresses a gap in literature by moving beyond traditional methods that often treat component failures as independent events. By capturing the interdependence between bridges, primarily through failure interactions, and system-wide effects, our method provides a more comprehensive criticality assessment. The simulation data provides a foundation for the framework, which applies to a wide variety of infrastructure networks and performance metrics. To demonstrate the method's effectiveness, a simplified transportation network from Shelby County, TN subjected to an earthquake event is analyzed. The proposed framework provides an effective approach for component ranking, suitable for decision-making where human intuition and simple methods are insufficient. Its broad applicability suggests a potential for large-scale and interdependent network problems.

Nd Isotopic Equilibration During Channelized Melt Transport Through the Lithosphere: A Feasibility Study Using Idealized Numerical Models

AbstractThis study is motivated by the observed variability in trace element isotopic and chemical compositions of primitive (Si52 wt %) basalts in southwest North America (SWNA) during the Cenozoic transition from subduction to extension. Specifically, we focus on processes that may explain the enigmatic observation that in some localities, basalts with low Ta/Th, consistent with parental melts in a subduction setting, have signatures consistent with continental lithospheric mantle (CLM). In locations with the oldest CLM (Proterozoic and Archean), Cenozoic basalts with low Ta/Th have well below zero. We model channelized magma transport through the CLM using simple 1D transport models to explore the extent to which diffusive and reactive mass exchange can modify Nd isotopic compositions via open system melt‐wallrock interactions. For geologically reasonable channel spacings and volume fractions, we quantify the reactive assimilation rates required for incoming melt with a different than the wall‐rock to undergo a substantial isotopic shift during 10 km channelized melt transport. In the presence of grain boundaries, enhanced diffusion between melt‐rich channels and melt‐poor surrounding rock contributes to isotopic equilibration, however this effect is not enough to explain observations; our models suggest a significant contribution from reactive assimilation of wall‐rock. Additionally our models support the idea that the observed covariability in Ta/Th and in Cenozoic basalts cannot be attributed to transport alone and must also reflect the transition from subduction‐related to extension‐related parental melts in SWNA.

A Super‐Foldable Lithium‐Ion Full Battery

AbstractDeveloping foldable power sources with simple transport and storage remains a significant challenge and an urgent need for the advancement of next‐generation wearable bioelectronics. In this study, super‐foldable lithium‐ion batteries are developed by integrating biomimetic methods, which effectively address the challenges of stress dispersion and mark a breakthrough in the field of super‐foldable devices. A synchronous three‐level biomimetic coupling technology is introduced and employed a strategy of radial compounding, gel‐electrostatic molding, and temperature‐programmed co‐pyrolysis. This approach allows us to simultaneously prepare a super‐foldable multi‐level “lotus structure” cathode and a highly compatible super‐foldable “peapods” structure anode. Remarkably, even after 500 000 cycles of repeated folding tests, the full battery maintains a high level of capacity stability, and the galvanostatic charge/discharge curves also exhibit a high degree of consistency. Furthermore, this battery can power an LED clock for over 2870 continuous minutes while undergoing in situ dynamic reciprocating folding, highlighting its substantial promise for practical applications. The super‐foldable battery represents a full‐chain innovation, extending from the super‐foldable substrate to the super‐foldable electrodes, and culminating in a super‐foldable full battery.

Temperature-dependent charge transport measurements unveil morphological insights in non-fullerene organic solar cells

The morphological analysis of bulk heterojunction (BHJ) active layer stands as a critical imperative for advancing the performance of future organic solar cells. Conventional characterization tools employed for morphological investigation often require substantial resources, both in cost and physical space, thereby imposing restraints on research endeavors in this domain. Here, we extend the application of charge carrier transport characterization beyond conventional mobility assessments, utilizing it as a table-top method for preliminary morphological screening in organic thin films. The investigation focuses on several high-performance BHJ systems that utilize typical “Y” non-fullerene acceptors. It involves in-depth transport studies, including temperature- and field-dependent transport characterizations. The resulting transport data are analyzed in detail using the Gaussian disorder model to extract key transport parameters, specifically the high-temperature limited mobility (μ∞) and positional disorder (∑). Integrating these transport parameters with morphological insights obtained through various characterization tools—including x-ray scattering, sensitive spectroscopy, and quantum chemistry simulation—provides a deep understanding of the intricate interplay between charge transport properties and morphological characteristics. The results reveal explicit relationships, associating μ∞ with the degree of molecular stacking in BHJs and ∑ with the structural disorder in molecule skeleton. Our findings point to the promising potential of utilizing a simple transport characterization technique for the early stage evaluation of thin film packing and geometric properties of organic materials.

Hybrid Eu(II)-bromide scintillators with efficient 5d-4f bandgap transition for X-ray imaging

Luminescent metal halides are attracting growing attention as scintillators for X-ray imaging in safety inspection, medical diagnosis, etc. Here we present brand-new hybrid Eu(II)-bromide scintillators, 1D type [Et4N]EuBr3·MeOH and 0D type [Me4N]6Eu5Br16·MeOH, with spin-allowed 5d-4f bandgap transition emission toward simplified carrier transport during scintillation process. The 1D/0D structures with edge/face -sharing [EuBr6]4− octahedra further contribute to lowing bandgaps and enhancing quantum confinement effect, enabling efficient scintillation performance (light yield ~73100 ± 800 Ph MeV−1, detect limit ~18.6 nGy s−1, X-ray afterglow ~ 1% @ 9.6 μs). We demonstrate the X-ray imaging with 27.3 lp mm−1 resolution by embedding Eu(II)-based scintillators into AAO film. Our results create the new family of low-dimensional rare-earth-based halides for scintillation and related optoelectronic applications.

Development of novel osteochondral scaffolds and related in vitro environment with the aid of chemical engineering principles

In tissue engineering, collaboration among experts from different fields is needed to design appropriate cell scaffolds and the required three-dimensional environment. Osteochondral tissue engineering is particularly challenging due to the need to provide scaffolds that imitate structural and compositional differences between two neighboring tissues, articular cartilage and bone, and the required complex biophysical environments for cultivating such scaffolds. This work focuses on two key objectives: first, to develop bilayered osteochondral scaffolds based on gellan gum and bioactive glass and, second, to create a biomimetic environment for scaffold characterization by designing and utilizing novel dual-medium cultivation bioreactor chambers. Basic chemical engineering principles were utilized to help achieve both aims. First, a simple heat transport model based on one-dimensional conduction was applied as a guideline for bilayer scaffold preparation, leading to the formation of a gelatinous upper part and a macroporous lower part with a thin, well-integrated interfacial zone. Second, a novel cultivation chamber was developed to be used in a dynamic compression bioreactor to provide possibilities for flow of two different media, such as chondrogenic and osteogenic. These chambers were utilized for characterization of the novel scaffolds with regard to bioactivity and stability under dynamic compression and fluid perfusion over 14 d, while flow distribution under different conditions was analyzed by a tracer method and residence time distribution analysis.

Enhanced photocatalytic performance of two-dimensional NixRe1-xSe2 (x = 0 & 0.25) crystalline material: Exploring its potential as a high-efficiency catalyst

Water pollution, stemming primarily from dye effluent discharge in urban and industrial zones, remains a critical environmental issue. Photocatalysis emerges as a promising eco-friendly, cost-effective, solar-dependent, and recyclable solution. This study synthesizes Ni0.25Re0.75Se2 via a simple Direct Vapour Transport (DVT) technique, exploring the impact of doping on ReSe2's structural, optical, and photocatalytic properties. Characterization techniques (PXRD, FESEM, EDAX, Raman spectroscopy, UV–visible absorbance spectroscopy, XPS) were employed for analysis. Photocatalytic experiments with organic dyes like Methylene Blue (MB), Acridine Orange (AO), Crystal Violet (CV) demonstrated efficient AO dye degradation (95.67 %) in 60 min using Ni0.25Re0.75Se2, showcasing effective catalytic properties under 20W LED bulb. Trapping experiments identified hydroxyl radicals and holes as pivotal for AO dye degradation. Ni0.25Re0.75Se2 exhibited stability under varying pH, non-leaching behavior, and retained efficiency over cycles, showcasing potential for sustained use in industrial wastewater treatment. This research advances sustainable solutions to combat water pollution in urban and industrial environments.

Modeling Water Transport in Polymer Electrolyte Membrane Electrolyzers Using a One-Dimensional Transport Model

In this work, we present a water transport model to quantify the movement of water across Nafion® membranes in a proton exchange membrane electrolyzer as a function of varying operating conditions and membrane parameters. This physics-based model is based on the three main water transport mechanisms: diffusion, electro-osmotic drag, and pressure-driven flow. Three sets of equations are obtained to model the movement of water on the cathode side – I. Material balances for hydrogen and water in the flow channel (z-direction), II. Water movement across the membrane in the x-direction, and III. Expressions for variable membrane properties to serve as model inputs. The condensation of water at the cathode is also modeled to understand the respective transport contributions from the vapor and liquid phases. The coupled equation sets are solved numerically with appropriate boundary conditions. An analytical solution is also obtained for the governing differential equation for the mole fraction of water in the vapor phase. This study is perhaps the first effort for a detailed physics-based transport model to predict the water transport in the electrolyzer in one dimension using the actual measured values for the physical parameters of the system. The model results are compared with the experimental data available for water transport, and a good agreement is observed over the wide range of current, temperature and pressure differentials. Further, with the help of this simple transport model, the numerical analysis is performed to delineate the effect of electrolyzer operating conditions on the net water transport across the membrane, water condensation at the cathode, individual contribution of the transport fluxes, and electrolyzer design. Finally, the model is exercised to simulate the dependence of water transport as a function of membrane thickness. This confirms the validity of the current approach of using thin reinforced membranes by electrolyzer fabricators. Figure 1

Congestion Transition on Random Walks on Graphs.

The formation of congestion on an urban road network is a key issue for the development of sustainable mobility in future smart cities. In this work, we propose a reductionist approach by studying the stationary states of a simple transport model using a random process on a graph, where each node represents a location and the link weights give the transition rates to move from one node to another, representing the mobility demand. Each node has a maximum flow rate and a maximum load capacity, and we assume that the average incoming flow equals the outgoing flow. In the approximation of the single-step process, we are able to analytically characterize the traffic load distribution on the single nodes using a local maximum entropy principle. Our results explain how congested nodes emerge as the total traffic load increases, analogous to a percolation transition where the appearance of a congested node is an independent random event. However, using numerical simulations, we show that in the more realistic case of synchronous dynamics for the nodes, entropic forces introduce correlations among the node states and favor the clustering of empty and congested nodes. Our aim is to highlight the universal properties of congestion formation and, in particular, to understand the role of traffic load fluctuations as a possible precursor of congestion in a transport network.