Flow Distance Research Articles

Modeling Cs-137 Migration in Groundwater due to Low Probability Event of Leaching from Near Surface Disposal Facility for Low Level Solid Radioactive Waste

In this paper, we present impact of Cesium-137 (Cs-137) disposal in a Near Surface Disposal Facility (NSDF) with respect to groundwater migration and its consumption for drinking. We employ the Multiple Area Source Model for simulating the fate of radionuclide in groundwater to evaluate its potential contamination due to extremely low probability event of leaching from the NSDF. The assessment conservatively assumes direct interaction between disposal trenches and the underlying aquifer neglecting the barrier provided by the unsaturated zone. Temporal profiles of concentration of Cs-137 at different down flow distances in groundwater are obtained over a period extending several years post-disposal. The results indicate that even under such a worst-case conservative scenario and for an annual disposal rate of 3 TBq/y for a period of 50y, the maximum Cs-137 concentration in groundwater remains significantly below the safe drinking water threshold of 10 Bq/L recommended by the World Health Organization. It is found that amount of Cs-137 generally disposed in NSDF is significantly lower than the allowable disposal limit corresponding to concentration defined for safe drinking water limit.

Potential Sites for Rainwater Harvesting Focusing on the Sustainable Development Goals Using Remote Sensing and Geographical Information System

An innovative way to combat water scarcity brought on by population increase and climate change is rainwater harvesting (RWH), particularly in arid and semiarid areas. Currently, Pakistan is facing major water issues due to underprivileged water resource management, climate change, land use changes, and the sustainability of local water resources. This research aims to find out the suitable sites and options for RWH structures in the Quetta district of Pakistan by integrating the depression depth technique, Boolean analysis, and weighted linear combination (WLC) with hydrological modeling (HM), multicriteria analysis (MCA), a geographic information system (GIS), and remote sensing (RS). To find suitable sites for RWH, a collection of twelve (12) thematic layers were used, including the slope (SL), land use land cover (LULC), subarea (SA), runoff depth (RD), drainage density (DD), lineament density (LD), infiltration number (IFN), distance from built-up area (DB), distance from roads (DR), distance from lakes (DL), maximum flow distance (MFD), and topographic wetness index (TWI). The Boolean analysis and WLC approach were integrated in the GIS environment. The consistency ratio (CR) was calculated to make sure the assigned weights to thematic layers were consistent. Overall, results show that 6.36% (167.418 km2), 14.34% (377.284 km2), 16.36% (430.444 km2), 18.92% (497.663 km2), and 18.64% (490.224 km2) of the area are in the categories of very high, high, moderate, low, and very low suitability, respectively, for RWH. RWH potential is restricted to 25.35% (666.86 km2) of the area. This research also identifies the five (5) best locations for checking dams and the ten (10) best locations for percolation tanks on the streams. The conducted suitability analysis will assist stakeholders in selecting the optimal locations for RWH structures, facilitating the storage of water, and addressing the severe water scarcity prevalent in the area. This study proposes a novel approach to handle the problems of water shortage in conjunction with environmental and socioeconomic pressures in order to achieve the sustainable development goals (SDGs).

Energy-economic-environmental analysis of bifacial photovoltaic thermal (BPVT) solar air collector with jet impingement

Jet impingement cooling enhances photovoltaic (PV) system efficiency by using high-speed fluid jets to reduce panel temperatures, improving performance and longevity. The effectiveness depends on factors like fluid flow rate, nozzle placement, and distance from the panel. While it boosts energy output, it may increase energy use for fluid circulation and add complexity to the system. This research explores a groundbreaking approach to enhancing the efficiency of bifacial photovoltaic thermal (BPVT) systems by integrating jet impingement technology. A novel design featuring a jet plate reflector is introduced, offering the dual benefit of cooling the PV panels while simultaneously reflecting light to optimize energy capture. The study comprehensively analyses the system’s performance, including energy output and a detailed techno-economic and environmental-economic evaluation. The modelling in this study was validated and reasonably consistent with experimental results. The system's output air temperature and thermal efficiency are 302.07–318.75 K and 33.83–62.28 %, respectively. The temperature and electrical efficiency range for PV systems are 304.39–339.54 K and 9.39–11.22 %. Reduced mass flow rate and increased solar irradiation are the most economically advantageous operating parameters for the proposed system, resulting in lower annual pumping costs and more significant annual energy gains for the system. CBR variations range from 0.1363 to 9.3445, with an average of 2. Additionally, by using BPVT with jet impingement to generate electricity rather than fossil fuels, it is possible to reduce annual carbon dioxide emissions by approximately 1.61 tons and save RM93.51 annually. In general, the proposed method should be used to minimize environmental pollution.

The effect of internal migration on regional growth in Italy: a dynamic spatial panel data analysis

This study assesses the effect of internal migration on regional growth in Italy at the NUTS-3 level over the period 2002-2019. The composition of the internal migration flows of the working-age population in Italy during the sample period appears substantially heterogeneous in nationality and labor skills. The analysis considers this heterogeneity, estimating various specifications of the dynamic spatial model and controlling for the endogeneity of migration variables through a control function approach. e evidence suggests that the internal migration of Italian citizens has a positive direct and spillover impact on regional growth, slowing down the convergence process. On the contrary, there is no evidence of a significant effect of internal migration of foreign citizens. Taking the skill composition of internal movements of Italian citizens into account, the adverse impact on convergence is magnified, thus corroborating the skill-selective hypothesis. Finally, the diverging impact of internal migration increases with the distance of migration flows.

The effects of tropical cyclone on the container shipping network: A case study of typhoon Ma-on (2022)

As climate change intensifies, tropical cyclones pose increasing challenges to container shipping networks (CSN). However, research related in this area remains insufficient. In this study, we analyzed the effects of Typhoon Ma-on on the CSN using over 776 million Automatic Identification System (AIS) trajectory signals. Our findings reveal that the typhoon not only altered the network structure of the CSN but also affected the importance of container ports, vessel flow, and travel distance fluctuations along shipping routes. After the typhoon, the recovery of the network’s connectivity and stability, as well as travel time fluctuations, was less robust compared to other aspects. Additionally, the impact ranges for port importance, vessel flow, and travel distance fluctuations were 1,750 km, 500 km, and 2,250 km, respectively, following an inverse distance decay pattern. These findings offer new insights for stakeholders to enhance the effectiveness of disaster prevention and mitigation policies.

Calculation Method for Bottomhole Flow Pressure in Co-layer Development of Multilayer Sandstone Reservoir

Abstract Accurately calculating the bottom hole flow pressure of a multi-layer stacked sandstone reservoir (hereinafter referred to as a multi-layer reservoir) is the basis for production splitting, oil well dynamic analysis, and reasonable work system determination in the development of multi-layer reservoirs. The bottomhole flow pressure model for single-layer oil reservoirs does not consider interlayer interference and the pressure drop caused by fluid flow in the wellbore, which doesn’t comply with the characteristics of multi-layer combined production, and the use of the maximum bottomhole flow pressure of the oil layer as the bottomhole flow pressure of each oil layer to adjust the production system of each oil layer doesn’t meet the requirements of other oil layer regulation. Firstly, starting from fluid mechanics, the frictional effect generated by fluid flow in the wellbore is systematically considered, and the relationship between wellbore frictional pressure drop and flow distance is established. The pressure drop formula generated by fluid flow in the wellbore is derived; Secondly, from the perspective of seepage mechanics, a formula for the bottom hole flow pressure of a single-layer reservoir was obtained. Combined with the expression for the difference in bottom hole flow pressure of each oil layer in the development of a multi-layer reservoir and the pressure drop expression for fluid flow in the wellbore, a bottom hole flow pressure model for each oil layer in the development of a multi-layer reservoir was established (hereinafter referred to as the multi-layer reservoir bottom hole flow pressure model). Substitute various parameters into the bottomhole flow pressure model of multi-layer oil reservoirs, and the error between the calculated values and the actual test values in the field is 0.10%~1.30%, with an average error of 0.82%, meeting the actual needs of the site. There is a significant difference in the bottom hole flow pressure values of each oil layer in the co production reservoir. The multi layer reservoir bottom hole flow pressure model can accurately calculate the bottom hole flow pressure of each oil layer, avoiding the inability to accurately adjust the production system of multiple oil layers for the same bottom hole flow pressure. It can provide technical support for the development of a reasonable drainage system for on-site co production oil wells and the realization of high and stable production.

Development of geopolymer and cement-based shotcrete mortar: Impact of mix design parameters and spraying process

Shotcrete mortar is used in various construction works, including repair, tunneling, mining, and slope stabilization, among others. Traditionally, cement is used to produce shotcrete mortars with high viscosity, flowability, and early strength. Geopolymers (GP) have the potential to replace cement in shotcrete mortars, owing to their ability to reduce the material’s environmental footprint without compromising performance. This investigation assesses the feasibility of utilizing fly ash and blast furnace slag-based GP mortars produced with dune sand in shotcrete applications while comparing them to cement-based mixtures. The GP and cement-based shotcrete mortars were designed to have similar yield stress values. The evaluated properties included the initial flow, thickness layer, rebound material, rheological properties, setting time, compressive strength, ultrasonic pulse velocity, and pull-off bonding strength. Test results showed direct relationships between the yield stress and initial flow values, as well as between the buildup thickness and plastic viscosity, revealing that GP mortars were suitable for shotcrete applications, specifically those produced with flow values of 18.5 cm or less. GP mixtures produced with higher slag content than fly ash, higher sand content compared to binder, higher SH molarity, and lower solution content achieved higher buildup thickness owing to their higher viscosity. In the second phase, the performance of four mixes with different initial flows was assessed at various pumping flow rates and distances between the wall and machine pipe nozzle. The findings confirmed that these spraying parameters are crucial to improve the shotcrete performance of GP mortar with varying fresh behaviors.

Characteristics of flow passing over Hydrofoil Crested Stepped Spillway

A spillway comprises several sections, primarily the crest and chute, essential for safe water flow from an upstream reservoir to a downstream river. Incorporating a hydrofoil crest and stepped chute features creates an efficient Hydrofoil-Crested Stepped Spillway (HCSS). The hydraulic features of the 60 HCSS models, which were designed through the National Advisory Committee for Aeronautics (NACA) equation, are assessed through laboratory experiments under a skimming flow regime, where the five hydrofoil formation indexes (t), three numbers of steps (Ns), and four chute angles (θ) are of concern. The findings indicate that an escalation in the ratio of upstream depth (yup) to spillway height (P), correlates with a rise in the discharge coefficient (Cd) in HCSSs. Furthermore, augmenting the t effectively boosts the Cd value. On average, the Cd value of the crest at t = 1 surpasses that at t = 0.2 by 20 %. This increase in t accentuates the curvature of the spillway crest, thereby enhancing the curvature of streamlines and reducing the flow distance therein. The Energy Dissipation Ratio (EDR) of HCSS is influenced by factors such as t (positively correlated), Ns (positively correlated), and θ (negatively correlated). Optimal performance of the HCSS is observed at t = 1, where both the Cd and EDR reach their peak values.

Travel distance estimation of landslide-induced debris flows by machine learning method in Nepal Himalaya after the Gorkha earthquake

Debris flows are more likely to be triggered in the earthquake-strike areas with a widespread presence of unstable slopes, causing severe casualties and changing the surrounding natural topography. In such scenario, estimating the travel distance of debris flows becomes crucial to understand the hazardous areas. Therefore, a hybrid machine learning model (GA-XGBoost) was employed to achieve a reliable estimation of debris-flow travel distance. This model was applied to the Nepal Himalayas, the site of the 2015 Gorkha earthquake. We selected four geomorphological factors for travel distance estimation. They are the volume of failure mass (VL), the height difference between the material source center and end point of movement mass (H), the mean gradient of the travel path (J), and the mean curvature of the travel path (C). Furthermore, to eliminate the noise information and enhance stability of input data, a principal component analysis (PCA) was used to generate three principal components (PC1, PC2, and PC3) from the selected factors to serve as input variables of model development. The performance of this model was evaluated using the assessment indexes, resulting in a mean absolute percentage error (MAPE) of 8.71%, a root mean square error (RMSE) of 144.3 m, and a mean absolute error (MAE) of 86.1 m. Four empirical approaches were also introduced for comparison analysis. Our proposed model has proven to be superior and effective, as the estimated results closely match the actual values. All the results affirm the suitability of our developed model for estimating the travel distance of landslide-induced debris flows following a strong earthquake.

Numerical investigation of heat transfer characteristics of hydrogen flow in a randomly packed bed

In this study, two randomly packed beds with small tube-to-particle diameter (D/d) ratios of D/d = 4 (PB-4) and D/d = 5 (PB-5) are constructed using the discrete element method (DEM). The pore-scale heat transfer characteristics of hydrogen flow at low pore Reynolds numbers (Rep < 100) are investigated using a DEM-CFD simulation approach, with the temperature-dependent thermo-properties of hydrogen being considered. Distinct local channeling flow patterns are revealed by detailed analyses of the flow fields in PB-4 and PB-5. The overall friction factors for both beds are found to agree well with empirical correlations. Notably, a faster spatial temperature increase is exhibited by PB-5, with a larger D/d ratio, as evidenced by a shorter axial distance for fully-heated hydrogen flow compared to PB-4. For the pore-scale heat transfer in the packed beds, the radial temperature profiles are compared at various heights of the packed beds depending on the radial porosity oscillation, in which the wall effect should be especially considered in the near-wall region. Furthermore, the axial pore-scale Nusselt number (Nup,axial) exhibits an inverse fluctuation with the axial porosity oscillation. Finally, the global Nusselt numbers (Nu) in the packed beds are analyzed under different operating conditions, which are in good agreement with empirical correlations.

Zebrafish as a rapid model system for early cardiotoxicity assessment of drugs

ObjectiveThere are some problems in the evaluation of drug cardiotoxicity in zebrafish, such as unsystematic indicators and weak sensitivity. This study aims to explore the advantages and disadvantages of various evaluation methods in rapid cardiotoxicity assessment, and to identify and establish representative and highly sensitive evaluation indicators. MethodsFour typical cardiotoxic drugs (Doxorubicin, 5-Fluorouracil, Ibuprofen and Lidocaine) with different concentrations were selected to act on zebrafish embryos. The death, cardiac malformation, heart rate, blood flow and sinus venosus-bulbus arteriosus (SV-BA) distance of zebrafish in each group were observed and recorded by stereo microscopy. The behavioral changes of zebrafish after drug treatment were counted and analyzed using a zebrafish behavior recorder. Adult zebrafish were used to screen the cardiotoxic expressed genes, and the spatiotemporal expression stability and concentration-dose dependence of the specifically highly expressed genes were studied. ResultsAll the 4 drugs can reduce the heart rate and blood flow velocity of zebrafish embryos to varying degrees, increase the SV-BA distance of zebrafish embryos, reduce the activity behavior of zebrafish embryos, and have different degrees of inhibitory effects on the cardiac function of zebrafish. Among the selected 12 genes expressed only in the heart, one and only CMLC1 showed high specific expression in the heart of zebrafish. However, doxorubicin did not affect the expression of CMLC1 gene in a concentration-dose dependent manner, and the other three drugs could significantly induce the up-regulation of CMLC1 gene expression. ConclusionEthology is a faster and more sensitive method than the traditional cardiotoxicity evaluation indicators (heart rate, blood flow velocity, and SV-BA distance). Zebrafish have a small number of highly heart-specific expressed genes and are not suitable for assessing cardiotoxicity based solely on heart-specific expression of circulating mRNA.

Capillary Flow-Based One-Minute Quantification of Amyloid Proteolysis.

Quantifying the formation and decomposition of amyloid is a crucial issue in the development of new drugs and therapies for treating amyloidosis. The current technologies for grasping amyloid formation and decomposition include fluorescence analysis using thioflavin-T, secondary structure analysis using circular dichroism, and image analysis using atomic force microscopy or transmission electron microscopy. These technologies typically require spectroscopic devices or expensive nanoscale imaging equipment and involve lengthy analysis, which limits the rapid screening of amyloid-degrading drugs. In this study, we introduce a technology for rapidly assessing amyloid decomposition using capillary flow-based paper (CFP). Amyloid solutions exhibit gel-like physical properties due to insoluble denatured polymers, resulting in a shorter flow distance on CFP compared to pure water. Experimental conditions were established to consistently control the flow distance based on a hen-egg-white lysozyme amyloid solution. It was confirmed that as amyloid is decomposed by trypsin, the flow distance increases on the CFP. Our method is highly useful for detecting changes in the gel properties of amyloid solutions within a minute, and we anticipate its use in the rapid, large-scale screening of anti-amyloid agents in the future.

Earth's longest lava flows erupted from its largest igneous province: The submarine Ontong Java Plateau

We use high-precision analyses of fresh basalt glasses from the submarine, Cretaceous Ontong Java Plateau (OJP) recovered by the Ocean Drilling Programs (ODP) to test for long submarine lava flows. Major elements and Cl show that glasses from ODP Holes 1185B and 1186A, which are 200 km apart, are compositionally identical and must have erupted simultaneously from the same well-mixed magma chamber. Identical CO2 contents show they erupted at the same water depth, but 1185B is directly downslope from 1186A and has a corrected basement depth that is >700 m deeper. Remarkably, <2 °C cooling took place over 200 km, requiring a cooling rate <0.01 °C/km.Further evidence of long flows is the lack of vesicles in OJP's glasses, in contrast to mid-ocean ridge basalt glasses that almost always contain vesicles and are often oversaturated in dissolved CO2. We propose that OJP's lavas degassed to saturation levels of dissolved CO2 +H2O and lost all bubbles because they remained liquid for much longer periods during long distance flow. Dissolved CO2+H2O are used to estimate paleoeruption depths which are compared to current corrected basement depths. Using a fixed value of plateau subsidence (500 m) we reconstruct flow distances of 0 to 900 km for eight lava groups from six drill sites. Eruption depths in Hole 807 C are 3040 m for Kwaimbaita-type lavas but 1110 m for Singgalo-type lavas that directly overlie them suggesting that the Singgalo lavas erupted 900 km away (near Site 1183).Paleoeruption depths for Cretaceous glasses from the Jurassic East Mariana and Nauru Basins adjacent to OJP are shallower than most glasses recovered from OJP even though their reconstructed basement depths are 1500–3800 m deeper. It is very likely that the basins’ lavas were erupted on OJP and flowed up to 1600 km: longer than any lava flow known on Earth. Flow distances are shorter (≤1000 km) if a plateau subsidence of 1500 m is used in the calculations. Extremely high Cl in Nauru Basin glasses also supports eruption from OJP. Long distance flow with minimal cooling was facilitated on OJP by favorable slopes, lack of barriers, insulation of rapidly forming glass, and possibly by flow within lava tubes. Lava effusion rates were probably >100 m/sec and flow rapid: >1 m/sec.

Hydrological connectivity and environment characteristics explain spatial variation in fish assemblages in a wet–dry tropical river

AbstractHydrological connectivity in river systems facilitates the movement of animals across riverine landscapes and influences fish habitat but is threatened by climate change and water resource developments. We studied fish assemblages across a large wet–dry tropical river system in northern Australia that is under consideration for new agricultural and water resource developments, which are expected to alter hydrological connectivity. We explored relationships between the environment and several biotic variables; fish taxonomic composition, species turnover, and species trait presence, quantifying how they were related to hydrological connectivity. Environmental dissimilarity of sites was influenced by hydrological connectivity variables, including flow, elevation, and river distance. Environment characteristics and hydrological connectivity together were important predictors of fish taxonomic composition. Fish species turnover was highest in headwater sites, and species presence absence was related to feeding and reproductive traits. Our results suggest that habitat specialists and species with reproductive traits that depend on hydrological connectivity, such as diadromous species, are most vulnerable to declines in relative abundance following a reduction in connectivity, which would lead to range contractions within catchments. Maintaining habitats that support taxonomically and functionally unique fish assemblages, such as wetlands and headwater streams, is important for maintaining biodiversity.

Studies on NOx formation and reduction characteristics in high-ash, low-volatile coal combustion by mechanism experiments and industrial-scale trials

Mechanism experiments were performed to investigate NOx formation and reduction during the combustion of high-ash, low-volatile coal. Additionally, industrial-scale trials were conducted to study the effects of air-staging degree on the combustion and NOx emission characteristics of high-ash coal on a 350 MW supercritical down-fired boiler. The results showed that the total BET specific surface area, total pore volume and porosity values of high-ash coal (HAC) and ultra-high-ash coal (UHAC) were all larger than those of normal-ash coal (NAC), whereas NAC contained more N-5 and N-6 than HAC and UHAC. The carbon layer structure of HAC char was less ordered and the content of hydroxyl group was relatively high. The overall NO reduction ratio obtained using the HAC char was higher than the value for the UHAC char. However, in the high temperature range of 1300–1400 °C, NO reduction associated with UHAC char was accelerated because of catalysis by ash. On increasing the excess oxygen ratio λ from 1.0 to 1.2, the char-N conversion shown by the UHAC char slowly increased and remained the lowest among the three chars. When burning UHAC, as the ratio of secondary to tertiary air fluxes, Rst, was decreased from 1.56 to 0.57, heating of the fuel-rich coal/air flow slowed and pulverized coal combustion was inhibited. The situation associated with HAC was different. At the Rst of 1.11, the ignition distance of fuel-rich flow was the shortest at 1.50 m, and the overall temperature in the furnace was the highest. However the NOx emissions at the furnace exit were as high as 715 mg/m3 (6 % O2) in this condition. Decreasing Rst to 0.57 reduced this value to 634 mg/m3 (6 % O2) with carbon levels in the fly ash and slag of 5.17 % and 3.67 %, respectively. Air-staging combustion is evidently a reasonable approach to controlling NOx emissions when burning HAC. While for UHAC, it was necessary to appropriately reduce the air-staging degree to enhance combustion and maintain low NOx emissions.

An AI-Based Method for Estimating the Potential Runout Distance of Post-Seismic Debris Flows

The widely distributed sediments following an earthquake presents a continuous threat to local residential areas and infrastructure. These materials become more easily mobilized due to reduced rainfall thresholds. Before establishing an effective management plan for debris flow hazards, it is crucial to determine the potential reach of these sediments. In this study, a deep learning-based method—Dual Attention Network (DAN)—was developed to predict the runout distance of potential debris flows after the 2022 Luding Earthquake, taking into account the topography and precipitation conditions. Given that the availability of reliable precipitation data remains a challenge, attributable to the scarcity of rain gauge stations and the relatively coarse resolution of satellite-based observations, our approach involved three key steps. First, we employed the DAN model to refine the Global Precipitation Measurement (GPM) data, enhancing its spatial and temporal resolution. This refinement was achieved by leveraging the correlation between precipitation and regional environment factors (REVs) at a seasonal scale. Second, the downscaled GPM underwent calibration using observations from rain gauge stations. Third, mean absolute error (MAE), mean square error (MSE), and root mean square error (RMSE) were employed to evaluate the performance of both the downscaling and calibration processes. Then the calibrated precipitation, catchment area, channel length, average channel gradient, and sediment volume were selected to develop a prediction model based on debris flows following the Wenchuan Earthquake. This model was applied to estimate the runout distance of potential debris flows after the Luding Earthquake. The results show that: (1) The calibrated GPM achieves an average MAE of 1.56 mm, surpassing the MAEs of original GPM (4.25 mm) and downscaled GPM (3.83 mm); (2) The developed prediction model reduces the prediction error by 40 m in comparison to an empirical equation; (3) The potential runout distance of debris flows after the Luding Earthquake reaches 0.77 km when intraday rainfall is 100 mm, while the minimum distance value is only 0.06 km. Overall, the developed model offers a scientific support for decision makers in taking reasonable measurements for loss reduction caused by post-seismic debris flows.

Centrifuge modelling of dry granular run-out processes under deflective Coriolis condition

Coriolis effects, encompassing the dilative, compressive, and deflective manifestations, constitute pivotal considerations in the centrifugal modelling of high-speed granular run-out processes. Notably, under the deflective Coriolis condition, the velocity component parallel to the rotational axis exerts no influence on the magnitude of Coriolis acceleration. This circumstance implies a potential mitigation of the Coriolis force's deflective impact. Regrettably, extant investigations predominantly emphasize the dilative and compressive Coriolis effects, largely neglecting the pragmatic import of the deflective Coriolis condition. In pursuit of this gap, a series of discrete element method (DEM) simulations have been conducted to scrutinize the feasibility of centrifugal modelling for dry granular run-out processes under deflective Coriolis conditions. The findings concerning the deflective Coriolis effect reveal a consistent rise in the run-out distance by 2%–16%, a modest increase in bulk flow velocity of under 4%, and a slight elevation in average flow depth by no more than 25%. These alterations display smaller dependence on the specific testing conditions due to the granular flow undergoing dual deflections in opposing directions. This underscores the significance and utility of the deflective Coriolis condition. Notably, the anticipated reduction in error in predicting the final run-out distance is substantial, potentially reaching a 150% improvement compared to predictions made under the dilative and compressive Coriolis conditions. Therefore, the deflective Coriolis condition is advised when the final run-out distance of the granular flow is the main concern. To mitigate the impact of Coriolis acceleration, a greater initial height of the granular column is recommended, with a height/width ratio exceeding 1, as the basal friction of the granular material plays a crucial role in mitigating the deflective Coriolis effect. For more transverse-uniform flow properties, the width of the granular column should be as large as possible.

3D-Printed Meat Paste Using Minimal Additive: Assessment of Rheological and Printing Behavior with Post-Processing Stability

Printing foods in the desired shape with minimal additives and their stability after printing are the most important points for 3D food technology. In this study, the effects of water (5%, 10%, 15%, and 20%) and salt (0.5%, 1%, 1.5%, and 2%) on the printability of meat paste were evaluated to achieve improved textural and rheological properties. The printing parameters were examined at every stage, starting from the line thickness of the printed product, until the final 3D printed product was obtained. Accordingly, meat printability determined using different ingredient flow speed (3, 3.5, 4, 4.5, and 5), fill factor (1.2%, 1.3%, 1.4%, 1.5%, and 1.6%) and distance between layers (1.2, 1.4, and 1.6 mm). Salt addition increased the firmness and consistency of the samples, while the viscosity, storage modulus, and loss modulus decreased with the addition of water. Considering the line thickness and outer length, the most appropriate shape was obtained with 10% water and 1.5% salt. The optimal ingredient flow speed, fill factor, and distance between layers at a constant printing speed (2500 mm/min) were 3, 1.2%, and 1.4 mm, respectively. Four-layer-infilled 3D-printed samples maintained their initial shape after cooking, regardless of the cooking method. However, only baked products maintained their initial shapes among full-infilled samples. Although water and salt have different functions in meat, the use of the appropriate ratio is necessary for 3D-printed meat-based products to provide printability and post-production stability. To sum up optimum parameters and road map for printing meat and meat products including leftover meats and low-value by-products were revealed.

The effects of aperture position and length in side-vented needles on root canal irrigation: A computational fluid dynamics study

IntroductionRoot canal irrigation is crucial for infection control during root canal treatment. Side-vented needles for positive pressure irrigation are commonly used in clinical practice. However, variations in needle design among manufacturers can impact the fluid dynamics of irrigation. This study aims to use computational fluid dynamics to explore the flow characteristics of different needle aperture lengths and positions, and their effects on the effectiveness and safety of irrigation, using a validated passive scalar transport numerical model. MethodsThe validation of the CFD irrigant model was achieved by comparing it with an in vitro irrigation experiment model. The CFD model used scalar concentration, while the in vitro experiment model used red dye tracing. Using a standard 30G side-vented needle as a reference, virtual needle models featuring four aperture lengths and three positions were created. These virtual irrigation needles were then placed in two root canal geometries for CFD simulation to evaluate fluid exchange capabilities and related fluid dynamic parameters. ResultsThe results of the CFD simulation, using a scalar transport model, closely matched the in vitro tracer tests for irrigation experiments across seven root canal geometries. The CFD analysis indicated that positioning the aperture lower increased the irrigant exchange distance. Notably, decreasing the aperture length to 0.25x, and positioning it at the lower end of the needle significantly increased exchange distance and shear stress, while reducing apical pressure. ConclusionsThese results indicate that the position and length of the aperture affect the exchange distance of irrigant flow, wall shear stress, and apical pressure. The CFD validation model for scalar transport, based on a steady state, can function as a valuable tool for optimizing the side-vented needle in research. Further research on the design of side-vented needles will enhance the understanding of flow characteristics beneficial for irrigation efficiency in clinical practice.

Experimental study on the penetration and evaporation characteristics of a liquid kerosene jet in the supersonic crossflow

The penetration and evaporation characteristics of a liquid kerosene jet in the supersonic crossflow were experimentally investigated in this study. The experiments were carried out in both cold and high-enthalpy inflows. Detailed spray images were obtained using planar laser scattering techniques. The structures of the spray field were further analyzed on the basis of high spatial and temporal resolution images. The results show that the atomization and evaporation characteristics of a liquid kerosene jet are related to the crossflow temperature, liquid–gas momentum flux ratio, and injection distance. It is found that the breakup process of a liquid jet is accelerated in the high-enthalpy inflow. To accurately describe the maximum flow distance along the direction that kerosene can reach in the state of droplets, the survival distance is defined. It is revealed that the penetration depth and survival distance of the liquid kerosene jet decrease clearly with increase in the crossflow temperature. For the cavity-based combustor, the liquid kerosene jet can mix more sufficiently in the cavity region by reducing the injection distance and liquid–gas momentum flux ratio.