Volume Throughput Research Articles

Enhancement of Overlimiting Current in a Three-Dimensional Hierarchical Micro/Nanofluidic System by Non-uniform Compartmentalization

Overlimiting current (OLC) is a non-linear current response that occurs related to an ion concentration polarization (ICP) phenomenon in micro/nanofluidic systems and holds great importance since it represents the rate of selective ion transportation through perm-selective structure. For last two decades, numerous studies of OLC have been reported about understanding the fundamentals of nanoelectrokinetics and enhancing ion transportation through perm-selective membranes. Recent study reported that the alignment of non-uniform microspace near the perm-selective membranes in two-dimensional micro/nanofluidic systems can significantly enhance OLC, i.e., overlimiting conductance (σOLC). This is attributed to recirculation flow induced by combination of unbalanced electroosmosis and induced pressure driven flow among non-uniform microspaces. However, 2D micro/nanofluidic systems have limited practicality due to their small volume and low throughput. Herein, we tested the OLC enhancement using 3D-printed hierarchical micro/nanofluidic systems with respect to the non-uniformity of microspaces. The 3D microspaces were fabricated as a mesh structure using a conventional 3D printer. By comparing current–voltage measurement with each type of mesh, we experimentally confirmed the generation of recirculation flow among non-uniform meshes and ionic current enhancement in 3D hierarchical micro/nanofluidic system. Also, we further investigated the enhancement of overlimiting conductance depending on the mesh pattern. Furthermore, we validated that this effect of microscale non-uniform compartmentalization, both increasing surface area and aligning non-uniform spaces, appears not only at low molar concentration but at high molar concentrations. This demonstration can offer a strategy to design optimal electrochemical systems where a perm-selective ion transportation is crucial.

Blending low-carbon hydrogen with natural gas: Impact on energy and life cycle emissions in natural gas pipelines

Hydrogen (H2) is considered an alternative energy carrier to reduce greenhouse gas (GHG) emissions related to power and heat generation. A quantitative analysis was conducted to estimate the energy intensity and GHG emissions associated with the transportation of NG/H2 mixture in high-pressure transmission pipeline, considering blending ratios up to 100% of low-carbon H2. The life cycle emissions were obtained by including upstream supply chain emissions, compression and transportation emissions, and end use combustion emissions of the NG/H2 blend. This study accounts for global warming potential of fugitive methane and H2 emissions associated with pipeline transportation of the blend in the life cycle analysis. A significant reduction in the overall life cycle GHG emissions can be achieved when delivering the same volume throughput but at a reduced energy flow to end users. However, to maintain the nominal energy throughput of the pipeline regardless of the H2 mole fraction, a maximum reduction of about 6% is obtained as the H2 mole fraction in the blend will be practically limited to approximately 30% H2 when the pipeline operates at capacity.

Empirical analysis of the development relationship between Shanghai shipping industry and primary industry based on VAR model

This study employs the Vector Autoregression (VAR) model to conduct an in-depth empirical analysis of the dynamic relationship between Shanghai’s shipping industry and the development of the primary sector from 2002 to 2022. The findings reveal that, as a globally significant maritime hub, the development of Shanghai’s shipping industry has a notable positive impact on the growth of the primary sector, particularly in agriculture and fisheries. Through ADF unit root tests, cointegration tests, and Granger causality tests, a stable long-term relationship was identified between shipping industry indicators, such as container throughput and total waterborne cargo transport volume, and the output value of the primary sector. Impulse response analysis and variance decomposition further reveal the critical roles and mechanisms through which the shipping industry influences the development of the primary sector. Based on these insights, the paper proposes policy recommendations aimed at strengthening the integrated development of shipping and the primary sector, promoting technological innovation in the shipping industry, optimizing the policy environment, enhancing environmental protection measures, and bolstering international cooperation. These strategies are intended to foster synergistic development between the two sectors and drive sustainable economic growth.

Is boarding compromising our residents' education? A national survey of emergency medicine program directors.

Boarding patients in the emergency department (ED) potentially affects resident education. Program director (PD) perceptions of the impact of boarding on their trainees have not been previously described. We surveyed a cross-sectional convenience sample of emergency medicine PDs using a mixed-methods approach to explore their perceptions of how boarding has affected their residents' training. Descriptive data were reported as percentages and differences were calculated using Pearson's chi-square test, with p < 0.05 considered significant. A framework model was used to qualitatively analyze free-text responses. A total of 170 responses were collected, for a response rate of 63%. Most respondents felt that boarding had at least some effect on resident education with 29%, 35%, 18%, and 12% noting "a little," "a moderate amount," "a lot," and "a great deal," respectively, and 5% noting "no effect at all." Respondents perceived a negative impact of boarding on resident education and training, with 80% reporting a "somewhat" or "extremely negative" effect, 18% feeling neutral, and 2% noting a "somewhat positive" effect. Most noted a "somewhat" or "extremely negative" effect on resident education in managing ED throughput (70%) and high patient volumes (66%). Fifty-four percent noted a "somewhat" or "extremely negative" impact on being involved in the initial workup of undifferentiated patients. Thirty-two percent saw a "somewhat" or "extremely positive" effect on learning the management of critically ill patients. Qualitative analysis of challenges, mitigation strategies, and resident feedback emphasized the lack of exposure to managing departmental patient flow, impact on bedside teaching, and need for flexibility in resident staffing. Most PDs agree that boarding negatively affects resident education and identify several strategies to mitigate the impact. These findings can help inform future interventions to optimize resident learning in the complex educational landscape of high ED boarding.

Influence of various pretreatments on molecular and rheological properties of a linear and a long-chain branched polypropylene

The influence of a mechanical or a thermal pretreatment of a linear (L-PP) and a long-chain branched polypropylene (LCB-PP) in the molten state was studied. The molar mass distributions and the branching structure were determined by high-temperature gel permeation chromatography HT-GPC coupled with laser-light scattering. The samples were extruded through long or short capillaries of various geometries corresponding to a predominant shear or elongational deformation. As a rheological probe, the extrudate swell at low stresses was measured for the differently pretreated samples. For the L-PP, neither molecular nor rheological changes were observed. However, the extrudate swell of the LCB-PP was found to decrease with increasing volume throughput. It was more strongly affected by shear in the capillary than by molecule stretching in the entry region. The smaller extrudate swell was accompanied by a decrease of the high molar mass tail of the LCB-PP, which could be the reason for the decay of swell, in principle. However, a comparable degradation of the high molar mass tail was obtained by a pure thermal treatment that was shown to leave the extrudate swell unchanged. This result and the unaffected branching structures found by high-temperature gel permeation chromatography (HT-GPC) support the hypothesis of a change of the branching topography by the mechanical pretreatment.

Organic metal chalcogenide-assisted metabolic molecular diagnosis of central precocious puberty.

Metabolic analysis in biofluids based on laser desorption/ionization mass spectrometry (LDI-MS), featuring rapidity, simplicity, small sample volume and high throughput, is expected to be a powerful diagnostic tool. Nevertheless, the signals of most metabolic biomarkers obtained by matrix-assisted LDI-MS are too limited to achieve a highly accurate diagnosis due to serious background interference. To address this issue, nanomaterials have been frequently adopted in LDI-MS as substrates. However, the "trial and error" approach still dominates the development of new substrates. Therefore, rational design of novel LDI-MS substrates showing high desorption/ionization efficiency and no background interference is extremely desired. Herein, four few-layered organic metal chalcogenides (OMCs) were precisely designed and for the first time investigated as substrates in LDI-MS, which allowed a favorable internal energy and charge transfer by changing the functional groups of organic ligands and metal nodes. As a result, the optimized OMC-assisted platform satisfyingly enhanced the mass signal by ≈10 000 fold in detecting typical metabolites and successfully detected different saccharides. In addition, a high accuracy diagnosis of central precocious puberty (CPP) with potential biomarkers of 12 metabolites was realized. This work is not only expected to provide a universal detection tool for large-scale clinical diagnosis, but also provides an idea for the design and selection of LDI-MS substrates.

Size Fractionation of Milliliter DNA Samples in Minutes Controlled by an Electric Field of ∼10 V.

DNA size fractionation is an essential tool in molecular biology and is used to isolate targets in a mixture characterized by a broad molecular-weight distribution. Microfluidics was thought to provide the opportunity to create devices capable of enhancing and speeding up the classical fractionation processes. However, this conjecture met limited success due to the low mass or volume throughput of these technologies. We describe the μLAF (μ-laboratory for DNA fractionation) technology for DNA size selection based on the stacking of molecules on films of ∼100 μm in thickness with 105 cm-2 pores ∼2 μm in diameter. Size selection is achieved by controlling the regime of electrohydrodynamic migration through the temporal modulation of an electric field. This technology allows the processing of milliliter-scale samples containing a DNA mass of several hundreds of ng within ∼10 min and the selection of DNA in virtually any size window spanning 200 to 1000 bp. We demonstrate that one operation suffices to fractionate sheared genomic DNA in up to six fractions with collection efficiencies of ∼20-40% and enrichment factors of ∼1.5-3-fold. These performances compare favorably in terms of speed and versatility to those of the current standards.

Rapid seaward expansion of seaport footprints worldwide

As global maritime traffic increases, seaports grow to accommodate and compete for higher volumes of trade throughput. However, growth trajectories of seaport footprints around the world have gone unmeasured, likely because of a lack of readily available spatio-temporal data. Here, we use geospatial analysis of global satellite imagery from 1990–2020 to show that 65 seaports among the world’s top 100 container ports, as ranked by reported throughput, have been expanding rapidly seaward. Collectively, these seaports have added approximately 978 km2 in gross port area in three decades through coastal land reclamation. We also find that the relationship between footprint expansion and throughput volume is highly variable among seaports. Understanding patterns of seaport expansion in space and time informs global assessments of critical infrastructure and supply chain vulnerability to climate-driven hazard. Seaport expansion also sets up complex trade-offs in the context of environmental impacts and climate adaptation.

Increasing Performance of Spiral-Wound Modules (SWMs) by Improving Stability against Axial Pressure Drop and Utilising Pulsed Flow.

Spacer-induced flow shadows and limited mechanical stability due to module construction and geometry are the main obstacles to improving the filtration performance and cleanability of microfiltration spiral-wound membranes (SWMs), applied to milk protein fractionation in this study. The goal of this study was first to improve filtration performance and cleanability by utilising pulsed flow in a modified pilot-scale filtration plant. The second goal was to enhance membrane stability against module deformation by flow-induced friction in the axial direction ("membrane telescoping"). This was accomplished by stabilising membrane layers, including spacers, at the membrane inlet by glue connections. Pulsed flow characteristics similar to those reported in previous lab-scale studies could be achieved by establishing an on/off bypass around the membrane module, thus enabling a high-frequency flow variation. Pulsed flow significantly increased filtration performance (target protein mass flow into the permeate increased by 26%) and cleaning success (protein removal increased by 28%). Furthermore, adding feed-side glue connections increased the mechanical membrane stability in terms of allowed volume throughput by ≥100% compared to unmodified modules, thus allowing operation with higher axial pressure drops, flow velocities and pulsation amplitudes.

Multiplexing System for Automated Characterization of a Capacitive Field‐Effect Sensor Array

In comparison to single‐analyte devices, multiplexed systems for a multianalyte detection offer a reduced assay time and sample volume, low cost, and high throughput. Herein, a multiplexing platform for an automated quasi‐simultaneous characterization of multiple (up to 16) capacitive field‐effect sensors by the capacitive–voltage (C–V) and the constant‐capacitance (ConCap) mode is presented. The sensors are mounted in a newly designed multicell arrangement with one common reference electrode and are electrically connected to the impedance analyzer via the base station. A Python script for the automated characterization of the sensors executes the user‐defined measurement protocol. The developed multiplexing system is tested for pH measurements and the label‐free detection of ligand‐stabilized, charged gold nanoparticles.

Time Series Data Mining: A Unifying View

Time series data are ubiquitous; large volumes of such data are routinely created in scientific, industrial, entertainment, medical and biological domains. Examples include ECG data, gait analysis, stock market quotes, machine health telemetry, search engine throughput volumes etc. VLDB has traditionally been home to much of the community's best research on time series, with three to eight papers on time series appearing in the conference each year. What do we want to do with such time series? Everything! Classification, clustering, joins, anomaly detection, motif discovery, similarity search, visualization, summarization, compression, segmentation, rule discovery etc. Rather than a deep dive in just one of these subtopics, in this tutorial I will show a surprisingly small set of high-level representations, definitions, distance measures and primitives can be combined to solve the first 90 to 99.9% of the problems listed above. The tutorial will be illustrated with numerous real-world examples created just for this tutorial, including examples from robotics, wearables, medical telemetry, astronomy, and (especially) animal behavior. Moreover, all sample datasets and code snippets will be released so that the tutorial attendees (and later, readers) can first reproduce the results demonstrated, before attempting similar analysis on their data.

Simultaneous multiple-droplet generation with meniscus filling on digital microfluidics chip

As digital microfluidics (DMF) becomes a popular approach to automating biochemical reactions for various fields, its applications requiring numerous droplets with high volume consistence in parallel analysis still present a great challenge. DMF conventionally utilizes the three-electrode method to split droplets one by one – it has low throughput and noticeable droplet volume variations. To address this challenge, a novel splitting method with a zigzag row-electrode design on electrowetting-based DMF chips is proposed. The liquid is first stretched on the row-electrode, then split by the electrode array. The row-electrode promotes the meniscus filling phenomena, providing larger overlapping areas, thereby stabilizing the volume of droplets generated. Twenty (20) droplets of 6–8 nL with the volumetric coefficient of variance (CV) at only 1.26% are simultaneously generated, excluding the droplets at both ends. Theoretical analysis is developed and validated by the experiments to realize the relationship of important geometrical parameters. This method can not only rapidly produce multiple daughter droplets with excellent droplet volume consistence, but also preserve the common DMF fabrication and actuation scheme without modification. It shows great promise for the DMF applications that require high-throughput downstream processes.

Evaluating the scalability of reconfigurable manufacturing systems at the design phase

To face market volatility, reconfigurable manufacturing systems (RMS) aim to efficiently and cost-effectively react to changes. We focus on one characteristic of RMS: the scalability (ability to adapt the volume of throughput). In the literature, the only few indicators for scalability are not always formally defined and usually only consider a partial view of scalability. Moreover, most of them are actually more suited for the configuration planning rather than for the design. However, the design of the RMS has a high impact on its scalability. We propose the first combinatorial definition of this problem and a new measure to fully assess the scalability of a system at the design phase. This measure, based on a multi-objective approach, can assess the scalability of single-product manufacturing systems, analysing all configurations that it can implement. We present numerical experiments to compare this indicator with a state-of-the-art scalability indicator and with some classical production line design indicators, and we show that future research should focus on scalability as a specific criterion to optimise during the design of an RMS. In addition, the results obtained allow us to infer some managerial insights on the best levers to use when performing a reconfiguration for scalability purpose.

Leaching of dissolved organic carbon from commercial reverse osmosis membranes exacerbates interferences in organic solute rejection during bench-scale filtration

Materials in contact with purified (e.g., Drinking water, ultrapure-water) water are sources of dissolved organic carbon which can increase the regrowth potential. Reverse osmosis (RO) membrane materials are composed of flexible polymers that are also in contact with treated water, but their contribution to DOC and microbial regrowth in bench-scale filtration studies is not reported. Bench-scale filtration studies use less volumetric throughput compared to pilot and full-scale filtration systems, which likely exacerbates the influence of leachates on for DOC measurement in permeates. This limits our ability to determine if standard membrane preparation procedures ensure sufficient removal of leachable organics. Migration of DOC from 8 different reverse osmosis membrane filters was assessed by two different experimental approaches; (1) Immersion assay—membranes were soaked in a pasteurized, isotonic water solution with a low and constant concentration of DOC. (2) Volume throughput (VT) test—Permeate was collected at defined VT steps to determine the impact of VT on the washout of DOC during system start-up. Test water from the immersion assay and the filtration test were analyzed with respect to (i) DOC (mg/L), (ii) microbial regrowth potential (% increase in bacterial activity), (iii) DOC fractional composition via LC-OCD. The presented study identified variations in the leachability of DOC between commercial RO membranes. Leaching of DOC from RO membranes varied by supplier and membrane composition. Alfa Laval RO98 exhibited the highest release of DOC compared to the other membranes tested during the immersion assay, suggested by an increase in test water DOC from 0.3 mg/L to 7.43 ± 1.54 mg/L, (n = 3) within 48 h. Aquaporin biomimetic-based membranes had the lowest release of DOC after 48 h of immersion (0.702 ± 0.17 mg DOC/L, n = 3). Higher concentrations of leached DOC did not lead to a higher regrowth potential on the released solute. Results of the filtration test demonstrate that DOC leaching from the membrane can exceed the point of flux-stabilisation, which is the common endpoint of membrane preparation. In all membranes tested, the chemical composition of DOC was dominated by low molecular weight acids, indicative of monomers used during membrane interfacial polymerization. The implication of this study suggests that on bench-scale filtration less volumetric throughput compared to pilot-full scale filtration exacerbates the influence of leachates on for example DOC measurement in permeates; promoting interferences in DOC permeate measurement and corresponding rejection coefficient. Relevance for full-scale filtration systems is limited due to higher volume throughputs applied during system start-up and commissioning.

Influence of traffic complexity on railway gravity hump classification yard performance and capacity

An optimal freight train plan requires practitioners to find a balance between mainline and yard efficiencies by adjusting the complexity of the yard operation and evaluating trade-offs between the throughput volume, number of blocks and number of trains handled at a given classification (marshalling) yard. To increase knowledge of these trade-offs, YardSYM is used to model the Belt Railway Company of Chicago (BRC) Clearing Yard, a major gravity hump classification yard that processes approximately 3000 railcars per day. The experimental design specifies traffic patterns of varying complexity designed to determine the fundamental relationship between yard throughput volume, the total number of blocks assembled in the yard, and the level of service. Simulation results indicate that yard performance decreases as railcar volume increases and as the number of blocks increases. The simulation results also demonstrate the challenge of two diametrically opposed objectives for yard operators: maximizing railcar connections to outbound trains while departing outbound trains on schedule. Improved knowledge of these relationships can be implemented to advance network, traffic assignment, and blocking models, and allow practitioners to make more informed hump yard operating decisions that improve the efficiency of carload traffic and manifest train operations.

The impact of volume and surgical throughput on outcomes in head and neck reconstruction: a systematic review

Background: Microvascular free tissue transfer is the standard of care for head and neck reconstruction. It is suggested that the volume of cases/surgical throughput might be linked to better free flap outcomes, following the pattern of other surgical disciplines. However, the literature evidence is unclear.

Unmasking the Resolution-Throughput Tradespace of Focused-Ion-Beam Machining.

Focused-ion-beam machining is a powerful process to fabricate complex nanostructures, often through a sacrificial mask that enables milling beyond the resolution limit of the ion beam. However, current understanding of this super-resolution effect is empirical in the spatial domain and nonexistent in the temporal domain. This article reports the primary study of this fundamental tradespace of resolution and throughput. Chromia functions well as a masking material due to its smooth, uniform, and amorphous structure. An efficient method of in-line metrology enables characterization of ion-beam focus by scanning electron microscopy. Fabrication and characterization of complex test structures through chromia and into silica probe the response of the bilayer to a focused beam of gallium cations, demonstrating super-resolution factors of up to 6 ± 2 and improvements to volume throughput of at least factors of 42 ± 2, with uncertainties denoting 95% coverage intervals. Tractable theory models the essential aspects of the super-resolution effect for various nanostructures. Application of the new tradespace increases the volume throughput of machining Fresnel lenses by a factor of 75, enabling the introduction of projection standards for optical microscopy. These results enable paradigm shifts of sacrificial masking from empirical to engineering design and from prototyping to manufacturing.

5G radio access networks: A survey

The fifth generation (5G) technology improves the user experience and creates new possibilities for a variety of applications, including transportation, device-to-device communication, agriculture, and manufacturing. These new use-cases significantly increase the number of users, volume of traffic, throughput, and latency. Hence, there is a need to modify the radio access network (RAN) for the 5G system. This study investigates the various RAN architectures such as cloud-RAN (CRAN), heterogeneous cloud-RAN (HCRAN), and fog-RAN (FRAN). The architectures are examined in a variety of contexts, including system efficiency, spectrum and energy efficiency, fronthaul capacity, latency, resource sharing and allocation, and so on. Also, current issues with these architectures are highlighted, as well as some existing remedies.

Ultrasensitive multiplexed chemiluminescent enzyme-linked immunosorbent assays in 384-well plates

We have developed an ultrasensitive multiplexed immunoassay using 384-well microtiter plates capable of detecting proteins at subfemtomolar concentrations that requires as little as 2.5 μL of sample. Arrays of up to 4 capture antibodies were patterned on the bottom of the wells of a 384-well plate either by directly printing the capture antibodies or by printing anti-peptide tag anchor antibodies and incubating these arrays with capture antibodies conjugated to the corresponding peptide tags (“customized” assays). Samples were incubated with the antibody arrays and shaken orbitally at 2000 rpm to achieve the greatest sensitivity. Chemiluminescence (CL) from immunocomplexes labeled with horseradish peroxidase was imaged across the entire plate to quantify the amount of protein bound to each antibody spot of the arrays. The 384-well assay had a throughput 5-fold greater than 96-well plates that was achieved from simultaneous imaging of CL in all 384-wells and the use of automated pipettors to allow parallel processing of 384 assays. We developed 4 assays based on the 384-well CL ELISA: a direct print assay for IL-10 (limit of detection (LOD) = 0.075 fM); a customized assay for IL-6 (0.22 fM); a customized pharmacokinetic (PK) assay for measuring adalimumab (7.3 pg/mL); and a customized 4-plex assay for IL-5 (0.1 fM), IL-6 (0.52 fM), IL-10 (0.2 fM), and TNF-α (3.2 fM). The sensitivity and precision of the cytokine assays were comparable to current ultrasensitive protein detection methods in 96-well formats. The PK assay for adalimumab was 650 times more sensitive than a commercially available 96-well plate ELISA. We used the 384-well CL ELISAs to measure endogenous levels of the cytokines in the serum and plasma of healthy humans: the mean concentrations and precision were comparable to those from 96-well immunoassays. This 384-well format with subfemtomolar sensitivity will enable ultrasensitive multiplexed immunoassays to be performed with higher throughput and lower sample volumes than currently possible, a particularly important capability for clinical studies in drug development.

Flow-based determination of lead exploiting in-syringe dispersive liquid-liquid micro-extraction in xylene and integrated spectrophotometric detection

A lab-in-syringe flow system exploiting dispersive liquid-liquid micro-extraction in a solvent lighter than water is proposed for the spectrophotometric determination of lead in industrial residual waters. The steps inherent to both liquid-liquid extraction and monitoring of the formed compound are in-syringe carried out. The classical carbon tetrachloride is not used as the extracting solvent, as it does not present the friendly characteristics inherent to the Green Analytical Chemistry. Aiming at a cleaner alternative for this determination, xylene is selected. Enrichment factor, linear dynamic range, detection limit, sample throughput and residue volume inherent to the proposed procedure were estimated as 36, 50.0–250 μg L−1, 9.0 μg L−1, 13 h−1, and 2.0 mL, respectively.