Hollow Density Research Articles

Disentangling the ecological value of tree hollows to wildlife along elevation gradients: The case of southern temperate forests

The ecological importance of tree hollows relies on environmental factors that influence microhabitat requirements for wildlife. Thus, the value of hollows as thermal microhabitats should increase with elevation, but understanding this phenomenon involves a separate assessment of hollow use and site occupancy. Here, we evaluated the use of tree hollows by vertebrates and invertebrates along elevational gradients in southern Chilean temperate forests. Camera trap and Bayesian models were used to analyze separately hollow use and site occupation. Four of seven invertebrate taxa and 21 of 25 vertebrate species used hollows. All lizard and mammal species (rodents, bats, kodkods, and opossums) were found using hollows, while 13 bird species (77 %) did it. The hollow occupation of only two species responded to elevation, with Chilean opossums being more likely to use hollows as elevation increased, while black-throated huet-huets exhibited the opposite pattern. Chucao and Magellanic tapaculos increased their occurrence probability as elevation increased while that of jewel and blue-bellied lizards increased with elevation. Giant bumblebees, austral thrushes, and Chilean opossums preferred hollows in evergreen (non-Nothofagaceae) tree species while huet-huets preferred hollows in Nothofagus trees. A strong positive association between hollow density and elevation was also found. These results suggest Chilean opossums benefit from using hollows at high altitudes due to their sensitivity to low temperatures while the lower availability of tree hollows at low altitudes causes black-throated huet-huets to be limited by hollows. Thus, wildlife conservation in these forests requires the maintenance of hollows in different tree species along elevational gradients.

Integrated lipidomics and network pharmacology analysis to determine how Gu Fu Sheng Capsule improves lipid metabolism in rats with steroid-induced osteonecrosis of the femoral head

BackgroundSteroid-induced osteonecrosis of the femoral head (SONFH) is a prevalent refractory condition in orthopedics, often causing high disability rates. Gu Fu Sheng Capsule (GFSC) is commonly used to treat SONFH during the early and intermediate stages. However, the precise underlying mechanism of action of GFSC remains elusive. ObjectiveTo elucidate the mechanism through which GFSC improves lipid metabolism in rats with SONFH. MethodsA rat model of SONFH was established by administering methylprednisolone and lipopolysaccharide. Micro-computed tomography assessed femoral head effects, while hematoxylin–eosin staining examined femoral head tissues. Pathological changes were evaluated using an automated biochemical analyzer to measure changes in serum lipid levels. Besides, quantitative lipidomics and network pharmacology were used to determine how GFSC impacts SONFH. qRT-PCR and Western blotting were performed to assess mRNA and protein expression levels of key targets. ResultsGFSC can enhance bone density and prevents surface collapse of the femoral head, improve hollow bone lacuna density, reduce adipocyte infiltration, minimize osteocyte cavities, regulate the serum lipid levels and enhance lipid metabolism in SONFH rats. Moreover, integrated lipidomics and network pharmacology suggested that GFSC affects lipid metabolism-related genes by regulating nine targets, thereby influencing four metabolites and two metabolic pathways, which may mainly be due to components in GFSC such as quercetin, tanshinone iia, berberine. Western blotting and qRT-PCR data highlighted that GFSC improves lipid metabolism by regulating TP53, HSP90AA1, and ESR1. ConclusionGFSC effectively retards SONFH progression, potentially attributed to its ability to regulate lipid metabolism.

Tree hollow decline in new forest reserves with a long history of logging

AbstractIn many parts of the world, achieving a target of 30% of land managed for conservation under the Kunming‐Montreal Global Biodiversity Framework will require the protection of land with a long history of management for production. In newly protected forests, past logging practices will have impacted key aspects of stand structure, including hollow‐bearing trees that provide critical habitat for vertebrate fauna. The impacts of past silvicultural practices on hollow density, distribution, type and longevity may necessitate targeted ameliorative actions. We investigated tree hollows in the largest river red gum (Eucalyptus camaldulensis Denh.) forest in the world, which had undergone logging‐induced woody thickening prior to being converted to a conservation reserve in 2010. We recorded stem diameters and hollows in living and dead trees in 66 two‐hectare plots. Our sites sampled two productivity states and a wide range of total tree densities. On all sites, we found that hollow‐bearing tree densities were lower than reference values for unlogged stands and average density had halved relative to reference values. We found no relationship between the density of hollow‐bearing trees and total tree density, but we did find a weak positive relationship with site productivity. Larger trees had more hollows, bigger hollows and a greater diversity of hollow sizes. However, of the 1254 hollow‐bearing trees recorded, 43% were dead, 48% of the dead trees had been ringbarked. The proportion of hollow‐bearing trees that were dead was positively correlated with tree size, with 60% of trees in the largest quartile (>105 cm) recorded as dead. The prevalence of dead hollow‐bearing trees suggests that the density and diversity of hollows will continue to decline and ameliorative actions should be considered. These results highlight the need to consider the legacy of past silvicultural practices in the management of newly created conservation reserves.

Sub-Nanogram Resolution Measurement of Inertial Mass and Density Using Magnetic-Field-Guided Bubble Microthruster.

Artificial micro/nanomotors using active particles hold vast potential in applications such as drug delivery and microfabrication. However, upgrading them to micro/nanorobots capable of performing precise tasks with sophisticated functions remains challenging. Bubble microthruster (BMT) is introduced, a variation of the bubble-driven microrobot, which focuses the energy from a collapsing microbubble to create an inertial impact on nearby target microparticles. Utilizing ultra-high-speed imaging, the microparticle mass and density is determined with sub-nanogram resolution based on the relaxation time characterizing the microparticle's transient response. Master curves of the BMT method are shown to be dependent on the viscosity of the solution. The BMT, controlled by a gamepad with magnetic-field guidance, precisely manipulates target microparticles, including bioparticles. Validation involves measuring the polystyrene microparticle mass and hollow glass microsphere density, and assessing the mouse embryo mass densities. The BMT technique presents a promising chip-free, real-time, highly maneuverable strategy that integrates bubble microrobot-based manipulation with precise bioparticle mass and density detection, which can facilitate microscale bioparticle characterizations such as embryo growth monitoring.

Nestbox use indicates declining arboreal mammals in an Australian savanna may be limited by tree hollow availability

In the tropical savannas of northern Australia, many native mammal species are experiencing rapid and ongoing declines due to multiple interacting threats. These mostly arboreal and semi-arboreal mammals are reliant on tree hollows for shelter, which may be contributing to their decline. We monitored 198 nestboxes over three years across a 100-km transect on Cobourg Peninsula, where a diverse arboreal mammal community still occurs. Most nestboxes (67%) were used by at least one of five mammal species, all of which are declining and four are threatened. Hollow density (proxied by eucalypt stand density) varied across sites, with the number of eucalypts (>20 cm DBH) ranging between 20 and 140 per hectare and averaging 74 ± 28 (SD) per hectare. Correspondingly, the likelihood and frequency of nestbox use by arboreal mammals increased with declining local tree hollow density, indicating that hollows are a critical limiting resource at the local scale for arboreal mammals in this region. Frequent, local disturbances e.g., fire and introduced species, contribute to threatening processes. Therefore, reversing the decline of arboreal mammals in Australia’s tropical savannas requires multiple management interventions, including conserving hollow-bearing trees as ecosystem assets.

Influence of A.C. Frequency on Hollow Magnetron Sputtering Discharge Parameters

In the present work, optical emission spectroscopy was used to diagnose the influence of A.C. power source frequency on the hollow magnetron sputtering discharge parameters (such as discharge emission, discharge current and voltage, glow discharge structure, temperature (Te) and electron number density (ne), Debye length (λD), and plasma parameter (ND) of constant pressure. The electron temperature and number density were determined using the Boltzmann plots and the Stark broadening methods, respectively. The results illustrate that the normal glow discharge structure is similar to the D.C. discharge mode. The magnetic field has no impact on the fundamental discharge parameter in both A.C. frequencies under study. On the other hand, the other discharge parameters (Te, ne, λD and ND) increase with increasing the magnetic field in both discharge frequencies. In addition, the increase in the frequency of the A.C. source current led to an increase in the discharge intensity emission and the other discharge parameters being studied. In this case, in frequency 7 kHz, Te surged from 0.685 eV to 0.839 eV, and ne experienced an increase from 3.088 x 1018 m-3 to 4.902 x 1018 m-3. At a frequency of 9 kHz, the electron temperature surged from 0.711eV to 0.911 eV. ne experienced an increase from 3.615 x 1018 m-3 to 6.749 x 1018 m-3.

Quantitative Analysis of the Physical Properties of Ti6Al4V Powders Used in a Powder Bed Fusion Based on 3D X-ray Computed Tomography Images.

The physical properties of Ti6Al4V powder affect the spreadability of the powder and uniformity of the powder bed, which had a great impact on the performance of built parts made by powder bed fusion technology. Micro-computed tomography is a well-established technique used to analyze the non-destructivity of the objects' interior. Ti6Al4V powders were scanned with micro-CT to show the internal and external information of all the particles. The morphology, particle size distribution, hollow particle ratio, density, inclusion, and specific surface area of the powder samples were quantitatively characterized, and the relationship of flowability with these physical properties was analyzed in this work. The research results of this article showed that micro-CT is an effective way to characterize these items, and can be developed as a standard method of powder physical properties in the future.

Improvement of core heat transport in NBI plasmas of heliotron J using high-intensity gas puffing

Controlling the heat transport profile is important for high performance in magnetically confined fusion plasmas. In this study, improved electron heat transport was achieved in neutral beam injection plasmas by applying high-intensity gas puffing (HIGP) on a stellarator/heliotron device called Heliotron J. Compared with conventional gas puffing (GP) fueling discharge, a higher and more peaked electron temperature profile was obtained, and the core ion temperature was slightly higher but similarly shaped. Using similar parameters, the electron density profile for HIGP remained similar and differed from the hollow density profile observed in electron cyclotron heating-eIBT plasma. Transport analysis using the FIT3D and TR-snap codes showed a clear reduction in the effective electron heat transport coefficient in the plasma core region. However, more detailed experiments are required to understand the mechanisms underlying this improvement fully.

Core transport modelling of the DTT full power scenario using different fuelling strategies

A theory-based integrated modelling work of plasma response to deuterium fuelling in the new Divertor Tokamak Test facility (DTT) is performed, using the 1.5D transport code JETTO with the quasi-linear anomalous transport model QuaLiKiz for the core region. The full power DTT scenario E1 is investigated. It is characterised by 28.8 MW of Electron Cyclotron Resonance Heating, 10 MW of Neutral Beam Injection and 6 MW of Ion Cyclotron Resonance Heating to the plasma. Plasma density and temperature profile evolution is calculated up to the separatrix using two different fuelling methods, gas puffing and pellet injection, and two different seeding gases, argon and neon. To sustain the desired pedestal density level with gas puffing a big amount of neutral flux at the separatrix is needed. The feasibility limits of the pumping system are exceeded, regardless of the type of impurity introduced, thus making the use of pellets mandatory. The simulations performed with pellet injection as fuelling method predict that the pedestal density is well sustained with realistic parameters foreseen for the DTT pellet injector. Strong dependence of the core density on the electron cyclotron resonance (ECR) power deposition profile is found. Trapped Electron Modes dominance, low outward flux and strongly hollow density in the inner core region are foreseen with central peaked ECR power deposition profile. Ion Temperature Gradient modes dominance, inward flux and robust density sustainment on the whole radial interval are predicted for spread ECR power deposition, though with central density close to the ECR cut-off limit and with peaked impurity densities. An intermediate deposition extension is found to sustain the whole density profile and to obtain flatter core densities, as previously predicted for the reference full power DTT scenario by fixed pedestal simulations. The ECR deposition is negligibly modified by refraction changes both during a single pellet cycle and after several pellet cycles, indicating full compatibility between the ECR system and the pellet injection system.

Light impurities: equilibrium, transport and density profiles in tokamak and stellarator plasmas

The density profiles of light impurities observed in recent decades in a relatively wide variety of experiments on tokamaks and stellarators are analyzed and modeled based on the concept of self-consistent equilibrium and transport of impurity charge states (Shurygin 2020 Nuclear Fusion 60 046001). The emphasis is on the formation of charge-radial equilibrium and its invariant properties affecting transport and density profile. The impurity invariant equilibrium arises due to random compatible charge-radial variations, linking the impurity motion into a general ergodic (Markovian) process governed by a matrix of final probabilities. More than 60 profiles of helium, boron and carbon with central accumulation, flat and hollow were accurately reproduced by invariant dimensionless transport functions. It is shown that the leading processes determining the formation of impurity invariant density profiles in stationary plasma are the processes of ionization-recombination, and not the transport of particles. Successive variations in the hollow density profiles of helium, boron, and carbon observed in experiments can be described as successive invariant profile changes in the recombination rate profiles. The invariant particle diffusive-convective profiles can be calculated directly from the impurity density profiles. A general empirical formula for equilibrium constant of light impurities was proposed.

Wildfire and Climate Impacts Tree Hollow Density in a Temperate Australian Forest

Tree hollows are an important landscape resource used by fauna for shelter, nesting, and predator avoidance. In fire-prone landscapes, wildfire and climate may impact hollow dynamics; however, assessments of their concurrent impacts are rare. We conducted a field survey at 80 sites in the Sydney Basin bioregion (Australia) to understand how fire frequency, fire severity, mean annual temperature, and mean annual precipitation concurrently impacted the site-density of small- (<5 cm entry width), medium- (5–10 cm entry width) and large-size (>10 cm entry width) tree hollows and tree basal scars (which mediate hollow formation via invertebrate access to heartwood), when tree-size and dead/live status were considered. A unimodal relationship occurred between medium- and large-sized hollow densities and fire frequency and severity, respectively, with hollow densities greatest at intermediate frequencies/severities. Increases of 1.82, 1.43, and 1.17 hollows per site were observed between the 1 (reference) and 2, 2 and 3, and 3 and >3 fire frequency categories. Increases of 1.26, 1.75 and 0.75 hollows per site were observed between the low (reference) and moderate, moderate and high, and high and very high fire severity categories. Fire severity was also positively associated with basal scar density, with increases of 2.52, 8.15, and 8.47 trees per site between the low (reference) and moderate, moderate and high, and high and very high categories. A weak positive and stronger negative association was observed between mean annual temperature and small-sized hollow and basal scar density, respectively. Dead and medium-sized tree density was positively associated with medium-sized hollow and basal scar tree density, respectively. Collectively, our results suggest that wildfires, and in some cases climate, have diverse and size-specific impacts on tree hollow and basal scar density. Our results imply that fire regimes that allow for moderately severe wildfire will promote larger-sized tree hollows, which are a limiting resource for many fauna species.

Preparation and characterization of superfine spherical TKX‐50 with a hollow structure by spray drying

AbstractMicro/nano energetic materials with regular morphologies exhibit high energy release efficiency, superior charge performance, and low mechanical sensitivity. Exploring dihydroxylammonium 5,5′‐bistetrazole‐1,1′‐diolate (TKX‐50) with spherical microstructures and excellent comprehensive properties is of great significance for potential applications. In this work, a kind of superfine spherical TKX‐50 was fabricated by spray drying method. The as‐prepared TKX‐50 had a narrow particle size distribution with d50=3.14 μm, high sphericity of 0.944 with hollow structure and bulk density of 1.851 g/cm3. And its formation mechanism was proposed. The results of XRD and FT‐IR demonstrated that spray drying would not change the crystal structure of TKX‐50. TG‐DSC results showed that the initial decomposition and the peak temperature of superfine spherical TKX‐50 was about 10 °C lower than raw TKX‐50, and the apparent activation energy was 4.584 kJ ⋅ mol−1 lower than raw TKX‐50, due to the dramatic change in morphology. TG‐DSC‐FTIR‐MS provided a new understanding of decomposition process of TKX‐50, and the results illustrated that the main gas products were N2, H2O, N2O, NH3, NO, NH2, CO2, and HCN. Superfine spherical TKX‐50 underwent similar decomposition path as raw TKX‐50 but stood out in its larger occupation of the first decomposition which meant a more complete decomposition and its faster rate of the whole decomposition process. More importantly, the impact sensitivity (H50) increased from 50.1 cm to 70.8 cm, and the friction sensitivity (P) decreased from 24 % to 0 %, showing improved safety performance.

A practical design equation for accurate quantification of CRRT filter design factors and convection effects.

Considering the increasing clinical need for continuous renal replacement therapy (CRRT), further improvement in therapeutic efficacy has become an important focus for researchers. Here, we designed nine CRRT filters with various combinations of hollow fiber packing density (PD) and housing shape (effective hollow fiber length (L) and inner housing diameter (D) ratio (L/D ratio)) to evaluate the clearance of middle molecular uremic toxins (MMs) via simulation of an in vitro continuous veno-venous hemodialysis treatment model. We also used Doppler ultrasonography to measure the maximum internal filtration flow rate (QIF-Max) as an aid; this approach facilitated an exploration of the impacts of various design factors on convection effects, while revealing the mechanisms influencing MM removal performance. Furthermore, we constructed a multiple linear regression model of design factors and QIF-Max, then conducted experimental verification. Finally, we proposed an accurate and practical design equation to quantify the design factors influencing CRRT filters and convection effects: , where N/D2 and L/D affect QIF-Max by 15.0% and 85.0%, respectively. This design equation was able to effectively quantify the convection effects of CRRT filters with different design factors, thereby predicting MM removal performance; this convenient design equation can support the development of CRRT-related products.

Effects of hollow fiber packing density and housing shape on the albumin filtration performance of CRRT filters

Continuous renal replacement therapy (CRRT) has become the most commonly used acute blood purification therapy for critically ill patients. As a key point of extracorporeal blood circulation, the CRRT filter plays a decisive role in therapeutic efficacy. However, few in vitro studies have been conducted on CRRT filters, particularly concerning the effects of design factors on filter effectiveness and safety profile; no comprehensive evaluation system has been established. Here, we designed nine CRRT filters with various combinations of hollow fiber packing density (PD) and housing shape (effective hollow fiber length (L) and inner housing diameter (D) ratio (L/D ratio)) and introduced a high-frequency sampling pressure monitor to accurately monitor small changes in transmembrane pressure (TMP) and ultrafiltration rate (UFR) over time. We also used concentration polarization mass transfer resistance (Rc), change in sieving coefficient (S) of albumin over time, and amount of albumin removed (Mfld) to investigate the effects of two design factors on albumin filtration performance and analyze the mechanism of protein filtration performance over time, thereby establishing a comprehensive in vitro evaluation system to explore the safety profile of CRRT filters. Our results showed that the nine CRRT filters designed with different combinations of PD (50%, 55%, and 60%) and L/D ratio (2.9, 5.3, and 9.3) were able to maintain stability in terms of hemodynamics and water permeability; the lowest Mfld was PD = 60% and L/D ratio = 9.3, which indicates that design factor optimization can effectively control albumin filtration, thereby improving the safety profile of CRRT filters.

Peaking and hollowness of low-Z impurity profiles: an interplay between ITG and TEM induced turbulent transport

The transport of low-Z impurities in fusion plasmas is dominated, in many regimes of interest, by ion temperature gradient (ITG) and trapped electron mode (TEM) turbulence. We use a statistical test-particle approach to analyze the effects of these drift instabilities on the transport coefficients. It is found that the convection of motion by the polarization drift drives an outward radial pinch via ITG and an inward pinch via TEM turbulence. Opposite radial pinches are driven by turbulent motion along magnetic field-lines. The interplay between these effects can explain the co-existence of peaked and hollow impurity density profiles observed in tokamak plasmas. The theoretical framework is validated through comparison with experimental data on the transport of Boron impurities.

Investigation of core impurity transport in DIII-D diverted negative triangularity plasmas

Tokamak operation at negative triangularity has been shown to offer high energy confinement without the typical disadvantages of edge pedestals (Marinoni et al 2021 Nucl. Fusion 61 116010). In this paper, we examine impurity transport in DIII-D diverted negative triangularity experiments. Analysis of charge exchange recombination spectroscopy reveals flat or hollow carbon density profiles in the core, and impurity confinement times consistently shorter than energy confinement times. Bayesian inferences of impurity transport coefficients based on laser blow-off injections and forward modeling via the Aurora package (Sciortino et al 2021 Plasma Phys. Control. Fusion 63 112001) show core cross-field diffusion to be higher in L-mode than in H-mode. Impurity profile shapes remain flat or hollow in all cases. Inferred radial profiles of diffusion and convection are compared to neoclassical, quasilinear gyrofluid, and nonlinear gyrokinetic simulations. Heat transport is observed to be better captured by reduced turbulence models with respect to particle transport. State-of-the-art gyrokinetic modeling compares favorably with measurements across multiple transport channels. Overall, these results suggest that diverted negative triangularity discharges may offer a path to a highly-radiative L-mode scenario with high core performance.

Impact of impurities on drift wave instabilities in reversed-field pinch plasmas.

The drift wave in the presence of impurity ions was investigated numerically in reversed-field pinch plasmas, using the gyrokinetic integral eigenmode equation. By comparing the results of regular and hollow plasma density profiles, it was found that the ion temperature gradient mode for the hollow density profile case is much harder to excite. For the impurity effects, when the impurity density gradient is opposite to the electrons, namely when L_{ez} (L_{ez}=L_{ne}/L_{nz} with 1/L_{n} being the density gradient scale length, and the subscript "e" and "z" indicates electrons and impurity ions, respectively) is negative, the impurities can enhance the instability. On the contrary, when L_{ez} is positive, the instability is stabilized. Regarding the trapped electron mode (TEM), the growth rate for plasmas with a hollow density profile remains smaller than that of the standard density gradient. There exists a threshold in L_{ez}. When L_{ez} is less than this value, the impurities destabilize the TEMs, while when L_{ez} is greater than this value, the impurities stabilize the TEMs. In addition, the influence of the collisionality on the TEMs was also studied.

Acoustic radiation force dependence on properties of elastic spherical shells in standing waves

In this study, we theoretically investigate the acoustic radiation force acting on elastic spherical shells in standing waves in the dimensionless frequency range of 0<ka<0.7 (k is the wave number in the host fluid and a is the outer radius of the spherical shells), we show that in the low-frequency range (0<ka<0.2), the acoustic radiation force on core–shell spheres can vary from positive to negative by decreasing the effective density and effective bulk modulus of the spherical shells, while the effective density and bulk modulus are dependent on the hollow ratio of the core–shell spheres, the density and bulk modulus ratios of the shell to the core. Thus, the core–shell spheres cannot only be trapped from the pressure node to the pressure antinode by increasing the hollow ratio or decreasing the shell’s density or longitudinal or shear velocity, but are also unresponsive to ultrasound waves with an optimal hollow ratio, density, or acoustic velocity of the shell. We further show that in the relatively low-frequency range of0<ka<0.7, the acoustic radiation force on core–shell spheres can be significantly enhanced around resonant frequencies. The acoustic radiation force could be enhanced at lower frequencies by increasing the hollow ratio or decreasing the shell’s density or shear wave velocity. Our results pave the way for optimising the design of core–shell particles for efficient ultrasound-mediated drug delivery.

Dynamic investigation and alleviative measures for the skidding phenomenon of lubricated rolling bearing under light load

The skidding phenomenon occurs during the operation of rolling bearing under the light load owing to the design error, which will intensify the surface damage and lead to noise and abnormal vibration. In this study, a skidding dynamics model of lubricated rolling bearing is established considering the interactions between the roller and races, as well as the cage. The effect of lubricant on the dynamic characteristics of the rolling bearing is characterized as the lubricating oil stiffness, central film thickness, time-varying friction coefficient between the roller and race, passing flow resistances of rollers, and resistance torques. In addition, the nonlinear contact and structure deformations of rollers are formulated. For mitigating the skidding phenomenon of the roller under light load, the effect of roller number, inside radius of the hollow roller, density and viscosity of the lubricant, interference fit, and radial load are analyzed. The results indicate that the skidding phenomenon of the roller is induced by the lesser tangential roller-race friction forces and larger passing flow resistances of rollers. It is helpful to intensify the interactions at the roller-race interface or/and decrease the running resistance by reducing the roller number, decreasing the lubricant density, or choosing the correct viscosity of the lubricant. Besides, the effect of interference fit and increasing radial load is significant on the premise of not changing the design parameters of the rolling bearing.

Effect of hollow fiber packing density and housing shape on the solute removal performance of CRRT filters for acute blood purification

Continuous renal replacement therapy (CRRT) has a good therapeutic effect in a variety of diseases, such as acute kidney injury. CRRT filters should feature small membrane surface area, excellent water permeability and solute removal performance for long-term use. Solute removal performance depends on the physicochemical structure of the dialysis membrane as well as on the housing design. On the basis of the same hollow fiber membrane, optimizing the housing design can maximize the performance of the dialysis membrane. In this article, we experimentally demonstrated the influence of hollow fiber packing density (PD) and housing shape (effective hollow fiber length (L) and inner housing diameter (D) ratio (L/D ratio)) on the performance of CRRT filters. In each continuous hemodialysis mode and post-diluted continuous hemodiafiltration mode, we tested nine CRRT filters with the same high-flux membrane but with different PDs (50%, 55%, and 60%) and L/D ratios (2.9, 5.3, and 9.3), and we evaluated the effect of different combinations of the two design factors on solute clearance. Our results showed that unlike with the clearance of small molecular weight solutes, the clearance of medium molecular weight solute was obviously affected by PD and L/D ratio, and the design providing the best removal of medium molecular solutes among the nine experiments was PD = 60% and L/D ratio = 9.3. This article will help address the lack of research on CRRT filter housing design as well as lead to the development of higher performance filters for acute blood purification.