Decrease In Flux Research Articles

Flexible Electromagnetic Tactile Sensor Based on Double‐Layer High‐Density MEMS Coils and Tilted Magnetic Column Array

AbstractWith the rapid development of wearable devices, tactile sensors have received extensive attention as supplements to vision and hearing. However, it remains challenging for a single tactile sensor to generate distinguishable electrical signals when receiving mechanical stimuli in different directions. Herein, a novel flexible electromagnetic tactile sensor (FETS) prepared by combining flexible double‐layer coils and a flexible tilted magnetic column array (TMCA) is presented. Flexible double‐layer high‐density coils are fabricated using the micro‐electromechanical system (MEMS) technology. The turns of the coil (1 × 1 cm) are 100, while both the line width and spacing of turns are 40 µm. TMCA is prepared using a template and magnetized along the axis direction. When a pulling force or pressure is applied to the TMCA, the magnetic flux decreases or increases correspondingly, allowing the FETS to accurately distinguish stimuli and produce different signals (−/+ or +/−). The FETS presents a sensitivity of up to 21.7 µV kPa−1 (0.05–10 kPa), a minimal magnetic field detection limit of 10 mT, a low‐pressure detection limit of 5 g, and good repeatability (5000 cycles). Additionally, the FETS is applied in robotic tactile testing, Morse code, and noncontact magnetic field recognition. It has potential applications in the Internet of Things (IoT) and information communication.

Estimation of heat flux entering the bone during the drilling process using the inverse heat transfer method

Drilling is one of the most important surgical steps and bone fracture repair. In this step, the temperature may exceed 47 °C and thermal necrosis may occur, which has irreversible consequences. Knowing the amount of heat transferred to the bone and its changes can be effective in recognizing this heat damage and minimizing it. In this research, it was tried to estimate the amount of heat flux entering the bone during the drilling process using the inverse heat transfer method. Drilling tests were performed on cow bone samples and the temperature changes at the hole location were measured using the inverse heat conduction transfer method. The amount of heat input was estimated. The K-type thermocouple is used to measure temperature. The diaphysis fragment of the cow's thigh (middle part), which has a length of about 90 mm and the thickness of the cortical bone in this range is about 8–10 mm, was used. Also, to ease the tests, the beginning and end parts of the fresh femur were cut with a saw. The results show that the maximum heat flux occurs earlier than the maximum temperature. It was observed that the maximum heat flux and the maximum temperature rise with the increase of the rotational speed and the diameter of the tool. As the feed speed rises, first the maximum temperature and maximum heat flux decrease and then increase. By tripling the feed speed, the maximum heat flux decreases by about 20%. The highest percentage rise in temperature and heat flux occurs with a rise in rotational speed, which is around 130–140%. After the rotational speed, increasing the drill diameter increases the temperature up to about 66.7%. The results can be used to prevent thermal necrosis because the maximum heat flux is visible before the occurrence of the maximum temperature.

Driving soil N2O emissions under nitrogen application by soil environmental factor changes in garlic-maize rotation systems

In multiple cropping systems, optimizing nitrogen (N) input can mitigate N2O emissions and sustain agricultural productivity in frequently disturbed environments. Nonetheless, there remains a notable gap in understanding the role of soil environment in the N application process. Hence, a three-annual field experiment spanning six growth seasons from 2019 to 2022 was conducted to assess the impacts of surface water filled-pore space (WFPS), NO3−−N, and meteorological factors under combined N applications during garlic (G: 300 and 240 kg N ha−1) and maize seasons (M: 220, 175, and 130 kg N ha−1) on soil N2O emissions and crop yields. The findings showed that reducing the annual N application rate by 45−150 kg ha−1 led to a significant decrease in N2O emission flux by 27.7%−69.4% and 30.7%−53.6% in maize and garlic season respectively, compared to conventional N application (G300M220). However, decreasing N application notably reduced garlic yield by 4.5–22.8%. Furthermore, reducing annual N application decreased net environmental and diminished net environmental and economic benefits (NEEB) by 3.7%−28.9%. Multiple regression analysis demonstrated that the residual NO3–−N in the soil before nitrogen application significantly influenced short-term N2O emissions post-application, while WFPS exerting a more pronounced effect during the maize season. Precipitation and temperature exhibited contrasting impacts on N2O emissions in the two crop seasons. Principal component analysis revealed that supplemental irrigation enhances crop yield in the maize growing season but also exacerbated N2O emissions due to the alternation of dry and wet conditions. Precipitation in the garlic growing season emerged as a crucial meteorological factor affecting crop yield and N2O emissions. The NEEB analysis suggested that reducing 45 kg N ha−1 in the maize season (G300M175) represents a more balanced N application approach to mitigate productivity and environmental risks in rotation systems. Therefore, accounting for the stimulating effect of soil environmental factors during the short-term N application process, adjusting irrigation practices based on seasonal precipitation and temperature variations can enhance productivity and reduce gaseous nitrogen losses in multiple cropping systems within semi-arid regions.

Quantifying the diffusion of suprathermal electrons by whistler waves between 0.2 and 1 AU with Solar Orbiter and Parker Solar Probe

Context. The evolution of the solar wind electron distribution function with heliocentric distance exhibits different features that are still unexplained, in particular, the fast decrease in the electron heat flux and the increase in the Strahl pitch angle width. Wave-particle interactions between electrons and whistler waves are often proposed to explain these phenomena. Aims. We aim to quantify the effect of whistler waves on suprathermal electrons as a function of heliocentric distance. Methods. We first performed a statistical analysis of whistler waves (occurrence and properties) observed by Solar Orbiter and Parker Solar Probe between 0.2 and 1 AU. The wave characteristics were then used to compute the diffusion coefficients for solar wind suprathermal electrons in the framework of quasi-linear theory. These coefficients were integrated to deduce the overall effect of whistler waves on electrons along their propagation. Results. About 110 000 whistler wave packets were detected and characterized in the plasma frame, including their direction of propagation with respect to the background magnetic field and their radial direction of propagation. Most waves are aligned with the magnetic field and only ∼0.5% of them have a propagation angle greater than 45°. Beyond 0.3 AU, it is almost exclusively quasi-parallel waves propagating anti-sunward (some of them are found sunward but are within switchbacks with a change of sign of the radial component of the background magnetic) that are observed. Thus, these waves are found to be Strahl-aligned and not counter-streaming. At 0.2 AU, we find both Strahl-aligned and counter-streaming quasi-parallel whistler waves. Conclusions. Beyond 0.3 AU, the integrated diffusion coefficients show that the observed waves are sufficient to explain the measured Strahl pitch angle evolution and effective in isotropizing the halo. Strahl diffusion is mainly attributed to whistler waves with a propagation angle of θ ∈ [15.45]°, although their origin has not yet been fully determined. Near 0.2 AU, counter-streaming whistler waves are able to diffuse the Strahl electrons more efficiently than the Strahl-aligned waves by two orders of magnitude.

Dual resistance Janus PDA/patterned PVDF membrane for membrane distillation with early wetting detection using electrochemical impedance spectroscopy

Membrane distillation (MD) is highly efficient in separating and removing water pollutants; however, it is susceptible to membrane wetting and fouling especially when treating low-surface tension pollutants such as oils and surfactants. To address these limitations, we fabricated a Janus polydopamine (PDA)/patterned polyvinylidene fluoride (PVDF) membrane with anti-wetting and anti-fouling properties via non-solvent- and vapor-induced phase separation. In the MD test with a NaCl feed solution with hourly sodium dodecyl sulfate injection, the Janus membrane with the hydrophobic patterned PVDF layer significantly delayed membrane wetting with only a slight trade-off in flux - an 8.6 % decrease in water vapor flux. Also, in the MD test using a NaCl feed solution containing 1000 mg L−1 of canola oil, the hydrophilic PDA layer of the Janus membrane effectively prevented the interaction between oil and the membrane surface. The wetting progression of the Janus membrane was systemically monitored using electrochemical impedance spectroscopy to identify the mechanism of its wetting behaviour and to detect and analyse the different wetting stages (i.e., non-wetting, partial wetting, and full wetting). Therefore, unlike conventional electrical conductivity measurement methods, the wetting front estimated using EIS enabled a more precise wetting detection during the DCMD operation.

Recovery of copper sulfate from acidic mine waters by membrane crystallization

The recovery of valuable resources from acid mine waters has attracted high interest in moving forward to a circular economy approach. In this work, acidic solutions were processed by a MCr process for the first time, allowing the recovery of copper in the form of copper sulfate crystals. PP and PTFE membranes were investigated at different temperatures (40–80 °C), showing a remarkable water flux decrease over time due to a severe accumulation of crystals on the surface of both PP and PTFE membranes, favoring the heterogeneous crystallization of CuSO4 on the membrane surface instead to the acid solution bulk. The flowrate and acid concentration were also evaluated to find operational conditions that can control crystal accumulation. The high accumulation of crystals was observed for all operating conditions except for a highly acidic condition of 100 g/L acid, where the membrane visually responded by repelling the crystals accumulation on the surface. The membranes were wholly characterized, observing a dramatic impact on the membrane morphology. Results show that copper crystallization by membranes is challenging. Still, considering new membrane materials, operating conditions could allow the process's feasibility.

Abstract 3300: Dual inhibition of PIKfyve and KRAS/MAPK as a potential for therapeutic strategy for pancreatic ductal adenocarcinoma

Abstract Background: PIKfyve is a lipid kinase that serves as the single source for PI(3,5)P2, a critical molecule for lysosome functions, including autophagy. Pancreatic Ductal Adenocarcinoma (PDAC) is known to utilize autophagy as well as other lysosome functions to survive in its harsh microenvironment. Considering the role of PIKfyve in autophagy, we hypothesized that PIKfyve is important for PDAC pathophysiology. Indeed, we screened multiple cell lines of different cancer lineages and found that PDAC cell lines were highly sensitive to PIKfyve inhibitors apilimod and ESK981. Given these results, we aimed to establish PIKfyve inhibition as a therapeutic strategy for PDAC. Importantly, this idea is rapidly translatable as both apilimod and ESK981 have both cleared phase-1 clinical trials. Additionally, PDAC nearly ubiquitously harbors a mutation in KRAS, leading to the overactivation of the KRAS-RAF-MEK-ERK pathway, which is known to be the driver of PDAC. Recent reports showed that inhibition of this pathway results in induction of autophagic flux as a protective mechanism in PDAC. Thus, we aimed to investigate the therapeutic potential of PIKfyve inhibition in blocking protective autophagy induced by KRAS/MAPK inhibition. Methods and results: In order to determine the potential of PIKfyve inhibition as a therapeutic for PDAC treatment, we first established that PIKfyve inhibition disrupts the autophagic flux in cells. Specifically, we used PIKfyve inhibitors ESK981 and apilimod as well as CRISPRi-mediated knockdown and saw a decrease in autophagic flux through western blot and GFP-LC3-RFP-LC3∆G-based autophagic flux probe analyses. Finally, PIKfyve inhibition decreased cell viability with IC50s in the nanomolar range.To evaluate the potential of combined inhibition of KRAS/MAPK and PIKfyve, we first confirmed that genetic or pharmacological KRAS/MAPK perturbation indeed increases autophagic flux utilizing the autophagic flux probe. Importantly, we found that PIKfyve inhibition attenuates the autophagic flux induced by KRAS/MAPK inhibition. Moreover, we determined that dual inhibition of PIKfyve and KRAS/MAPK resulted in synergistic growth inhibition employing CellTiter-Glo-based synergy assays. Further, to investigate the in vivo potential of this combination, we utilized a syngeneic orthotopic model of PDAC. Surprisingly, most mice were cured when treated with both ESK981 and trametinib while each individual treatment only modestly decreased tumor burden. Additionally, we established a patient-derived xenograft model where mice treated with a combination of ESK981 and trametinib (MEK inhibitor) or ESK981 and MRTX-1133 (KRASG12D inhibitor) displayed substantial tumor regression in comparison to single treatment or control groups. Taken together, the dual inhibition of PIKfyve and KRAS holds promise as a therapeutic strategy for PDAC treatment. Citation Format: Jasmine P. Wisniewski, Caleb Cheng, Bailey Jackson, Ahmet Korkaya, Sydney Peters, Yuanyuan Qiao, Costas A. Lyssiotis, Arul M. Chinnaiyan. Dual inhibition of PIKfyve and KRAS/MAPK as a potential for therapeutic strategy for pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3300.

Coupling a Simple and Generic Membrane Fouling Model with Biological Dynamics: Application to the Modeling of an Anaerobic Membrane BioReactor (AnMBR).

A simple model is developed for membrane fouling, taking into account two main fouling phenomena: cake formation, due to attached solids on the membrane surface, and pore clogging, due to retained compounds inside the pores. The model is coupled with a simple anaerobic digestion model for describing the dynamics of an anaerobic membrane bioreactor (AnMBR). In simulations, we investigate its qualitative behavior: it is shown that the model exhibits satisfying properties in terms of a flux decrease due to membrane fouling. Comparing simulation and experimental data, the model is shown to predict quite well the dynamics of an AnMBR. The simulated flux best fits the experimental flux with a correlation coefficient r2=0.968 for the calibration data set and r2=0.938 for the validation data set. General discussions are given on possible control strategies to limit fouling and optimize the flux production. We show in simulations that these strategies allow one to increase the mean production flux to 33 L/(h·m2),whereas without control, it was 18 L/(h·m2).

Pool boiling heat transfer of ammonia outside enhanced tubes with various fin structures

Pool boiling heat transfer of ammonia on a smooth tube and three enhanced tubes was investigated at the saturation pressure ranging from 6.15 to 11.7 bar, which corresponds to the saturation temperature from 10 to 30 °C. The test tube with a length of 796 mm was immersed in the liquid pool of ammonia inside a cylindrical chamber having an internal diameter of 254.4 mm, and convection or pool boiling heat transfer outside the test tube was generated by flowing hot water through the tube. Three enhanced tubes of a low-finned tube (Low-fin), a low-finned tube with oblique cuttings (Turbo-C), and a finned tube having re-entrant cavities (Turbo-E) were prepared to examine the pool boiling enhancement on various finned tubes. Boiling hysteresis on the smooth tube was observed between when the heat flux increases and when the heat flux decreases, which resulted in the deviation of the heat transfer coefficients from the previous correlations when the heat flux decreases. A suitable correlation was suggested to compensate for the deviation of the heat transfer coefficients in case of decreasing the heat flux by modifying the Stephan-Abdelsalam correlation. Three enhanced tubes exhibited considerable enhancement in the heat transfer coefficients compared with the smooth tube, and boiling performance on the Turbo-E tube having re-entrant cavities was highly affected by the variation of the bubble diameter according to the saturation pressure. Enhancement factors of the enhanced tubes were obtained from the ratio of thermal conductance on the enhanced tube to that on the smooth tube.

Study of accelerator-based epithermal neutron flux depending on Li and Be targets

The Li(p,n) and Be(p,n) reactions are widely used as accelerator-based neutron sources for boron neutron capture therapy (BNCT). Because the energy of the neutrons produced by these reactions is high for BNCT, a moderator is required to reduce the energy to the epithermal energy region. The neutron yields and energy spectra derived from the Li(p,n) and Be(p,n) reactions vary with the incident proton energy; a high proton energy results in a high neutron yield. However, a high proton energy can also increase the neutron energy, and in this case, a high neutron energy requires a thick moderator, which decreases the epithermal neutron flux. Notably, these tradeoffs are not completely clear. Furthermore, the upper limit of the epithermal neutron energy used in different BCNT facilities is not the same. Therefore, epithermal neutron flux estimation with applying an appropriate moderator is necessary for comparing epithernal neutron flux depending on the proton energy, target type, and epithermal neutron range definition.In this study, GEANT4 simulations were performed to determine effective moderator materials and thicknesses. After applying a moderator, we examined the epithermal neutron flux by changing the conditions that can influence the epithermal neutron flux, such as the proton energy, target species (Li and Be), and different definitions of the epithermal neutron region. The results showed that the epithermal neutron flux increases with the increasing proton energy until a certain level for both Li and Be targets. For proton energies above 3 MeV for the Li target and above 7 MeV for the Be target, the epithermal neutron flux decreases or its increase rate gradually decreases. And, when the upper energy limit of the epithermal neutron range is changed from 10 keV to 20 keV or 40 keV, the epithermal neutron flux is more than 109 cm−2 s−1 at a proton energy of 3 MeV for Li target and 8 MeV for Be target.

How high salt shock affects performance and membrane fouling characteristics of a halophilic membrane bioreactor used for treating hypersaline wastewater

In the present study, the effect of short-term salt shocks (13% and 20%) on the performance of a halophilic MBR bioreactor used to treat a hypersaline (5% salt) synthetic wastewater was considered. 13% and 20% salt shocks resulted in a transient and permanent decrease in chemical oxygen demand removal efficiency, respectively which could be correlated with soluble microbial products (SMP) concentration and specific oxygen uptake rate values of the halophilic population. DNA leakage tests suggested that both 13% and 20% short-term salt shocks resulted in some cell structural damage. During both 13% and 20% salt shocks mixed liquor SMP, extracellular polymeric substances (EPS), zeta potential and endogenous respiration increased while relative hydrophobicity, EPSp/EPSc and exogenous respiration decreased; in both cases, however, the pre-shock values for these parameters were restored after the removal of the salt shock. 13% salt shock resulted in a transient increase in the membrane fouling rate and a permanent rise in total membrane resistance (Rt). On the other hand, both membrane fouling rate and Rt increased during 20% salt shock. Membrane fouling rate initially reduced after the 20% salt shock removal but after 5 days a “TMP jump” occurred. The latter was caused by the higher steady state SMPc and SMPp concentrations after removal of 20% salt shock compared to pre-shock values. This might have either resulted in a decrease in critical flux or an increase in local flux above critical flux in some parts of the membrane. The contribution of cake layer resistance to overall membrane resistance increased after the 13% and 20% salt shocks. The findings of the present study reveal the robustness of halophilic MBRs against salt shocks in the treatment of hypersaline wastewater. However, in cases of very high salt shocks, appropriate membrane fouling reduction strategies should be carried out during its operation.

Controlled architecture of multi-defense anti-fouling forward osmosis membrane for efficient shale gas wastewater treatment

Forward osmosis (FO) membrane process facilitates effective treatment of shale gas wastewater (SGW) due to its tolerance to high salinity and exceptional separation performance. However, serious membrane fouling remains a challenge regarding the complexity of realistic SGW. To address the fouling issues, controlled block copolymer architecture was constructed on the FO membrane surface to achieve combined effect of oil-resistance, self-regenerating, and fouling mitigation. In the modification process, zwitterionic polymer with strong hydrophilicity and fluoropolymers with low surface energy were successively grafted to the membrane active layer by atom transfer radical polymerization. The outermost fluoropolymer layer with low surface energy imparts the membrane with anti-oil and self-regenerating capabilities. Meanwhile, the strong hydration effect of the zwitterionic polymer ensures that nonspecific foulants breaking through the outermost defense are kept away from the membrane surface. According to the Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, the modified FO membrane exhibited a significantly higher total interaction energy (ΔGTOT) compared to the pristine membrane when exposed to various types of model foulants (bovine serum albumin, humic acid, sodium alginate, mineral oil). Furthermore, the advantage of having multiple defense mechanisms was further substantiated through dynamic filtration tests with realistic SGW. In comparison to the pristine TFC membrane, the modified membrane not only experienced a much smaller decrease in water flux (reduced by 52%) during fouling but also an exceptional flux recovery after cleaning (∼97%). These findings underscore that the modified FO membranes greatly mitigated membrane fouling associated with SGW through the synergistic interplay between a zwitterionic polymer and a low surface energy material, highlighting its promising potential in SGW treatment via membrane technology.

Can plant extracts be directly used in the fabrication of polymeric membranes for enhanced performance? A study on ultrafiltration membranes with Lycopodium

In this study, flat sheet PVDF membranes containing Lycopodium extracted with acetone and NMP were fabricated using the phase inversion method. When acetone was used as a solvent, PWF and reversible fouling rates were decreased. On the other hand, the PWF of NMP membranes fabricated with 0 %L, 1 %L, 2.5 %L, and 5 %L concentrations were found to be 198, 189, 167, and 148 L/m2.h, respectively. Although a decrease in fluxes was observed, an increase in FRR and reversible fouling rates was observed. Moreover, according to CLSM results, the live/dead cell ratio in the 5 %L-NMP membrane decreased from 16.7 to 0.7. Membranes with improved antifouling and antimicrobial properties were obtained by direct Lycopodium extraction in NMP. It is believed that these environmentally friendly membranes, produced through a more sustainable method, will perform well, especially in MBR applications.

Identification of HK3 as a promising immunomodulatory and prognostic target in sepsis-induced acute lung injury

BackgroundSepsis is a life-threatening global disease with a significant impact on human health. Acute lung injury (ALI) has been identified as one of the primary causes of mortality in septic patients. This study aimed to identify candidate genes involved in sepsis-induced ALI through a comprehensive approach combining bioinformatics analysis and experimental validation. MethodsThe datasets GSE65682 and GSE32707 obtained from the Gene Expression Omnibus database were merged to screen for sepsis-induced ALI related differentially expressed genes (DEGs). Functional enrichment and immune infiltration analyses were conducted on DGEs, with the construction of protein-protein interaction (PPI) networks to identify hub genes. In vitro and in vivo models of sepsis-induced ALI were used to study the expression and function of hexokinase 3 (HK3) using various techniques including Western blot, real-time PCR, immunohistochemistry, immunofluorescence, Cell Counting Kit-8, Enzyme-linked immunosorbent assay, and flow cytometry. ResultsThe results of bioinformatics analysis have identified HK3, MMP9, and S100A8 as hub genes with diagnostic and prognostic significance for sepsis-induced ALI. The HK3 has profound effects on sepsis-induced ALI and exhibits a correlation with immune regulation. Experimental results showed increased HK3 expression in lung tissue of septic mice, particularly in bronchial and alveolar epithelial cells. In vitro studies demonstrated upregulation of HK3 in lipopolysaccharide (LPS)-stimulated lung epithelial cells, with cytoplasmic localization around the nucleus. Interestingly, following the knockdown of HK3 expression, lung epithelial cells exhibited a significant decrease in proliferation activity and glycolytic flux, accompanied by an increase in cellular inflammatory response, oxidative stress, and cell apoptosis. ConclusionsIt was observed for the first time that HK3 plays a crucial role in the progression of sepsis-induced ALI and may be a valuable target for immunomodulation and therapy.Bioinformatics analysis identified HK3, MMP9, and S100A8 as hub genes with diagnostic and prognostic relevance in sepsis-induced ALI. Experimental findings showed increased HK3 expression in the lung tissue of septic mice, particularly in bronchial and alveolar epithelial cells. In vitro experiments demonstrated increased HK3 levels in lung epithelial cells stimulated with LPS, with cytoplasmic localization near the nucleus. Knockdown of HK3 expression resulted in decreased proliferation activity and glycolytic flux, increased inflammatory response, oxidative stress, and cell apoptosis in lung epithelial cells.

Variability in surface CO2 flux: Implication for monitoring surface emission from geothermal fields

In the last decade the international push for the development of various renewable energy and the increase of the carbon tax for emitters, has put high enthalpy geothermal on a hot seat. Anthropic geothermal emissions in volcanic areas are not negligible due to the inherent nature of their volcanic setting but are counted regardless, similarly to a gas or coal power plant, despite their non-fossil carbon origin. Natural volcanic emissions are however poorly constrained due to the lack of field scale soil CO2 flux assessments. In this study, we analyse the temporal and spatial variations of soil CO2 flux and soil temperature in the Taupō region, Taupō Volcanic Zone, New Zealand, in the light of seasonal variation, field utilisation, and seismicity. Fortnightly monitoring between 2019 and 2023 at 8 sites across the Tauhara and Wairakei geothermal fields provides insight into changes of seasonal variations and geothermal activities. To understand the broader distribution of natural degassing and to compare the CO2 flux over decades, we repeated the CO2 flux survey between 2019 and 2023 and compared to previous results at Karapiti, Wairakei geothermal field (2004, 2018), Ring of Fire, Tauhara geothermal field (2006), and Rotokawa geothermal field (2003, 2011). Similar emissions but a change in the spatial distribution at Tauhara geothermal field suggests that human surface development has affected permeability in the shallow subsurface. In contrast, a similar spatial distribution of flux, but higher emissions, at Karapiti, Wairakei indicates the recovery or modification of reservoir pressure. Finally, a decrease of total emission flux of the natural geothermal features at Rotokawa coincides with the decrease of CO2eq emissions at the power stations. This study showcases the complexity and uncertainties of natural CO2 emission calculations and provides recommendations for future monitoring studies.

Impacts of physical parameterization scheme of snow and soil properties over the Tibetan Plateau on the simulation of summer rainfall in China

Accurate representation of soil and snow state variables in the land surface model is crucial for good simulation results. In order to investigate the potential impacts of the overestimated snow cover over the Tibetan Plateau (TP) on precipitation over China, we designed comparative experiments over TP with and without updated soil texture data, soil hydrological parameters, and the fresh snow density scheme to address this issue with the Weather Research and Forecasting Model (WRF). The results show that snow cover fraction (SCF) and surface albedo in winter on the TP were overestimated in the WRF control experiment (CTL), with albedo bias exceeding 0.4 in the western TP. The SCF in the WRF improved experiment (WRFIM) is about 8% lower than that of the CTL, and the bias is decreased to 0.2–0.3 in the interior of the TP. The thermal and dynamic effects of the TP in winter have a significant impact on the weather and climate of East Asia during summer. Thus, the simulated summer rainfall bias is significantly reduced by WRFIM in North China, and the mid-lower reaches of the Yangtze River, along with the spatial correlation coefficient between the observed-based and WRF-simulated rainfall increased from 0.76 in CTL to 0.88 in WRFIM. The WRFIM-simulated reductions in snow cover and albedo cause a decrease in upward shortwave radiation and eventually increase net surface radiation. The horizontal temperature gradient of the atmosphere is increased in the WRFIM compared to the CTL, and the increased temperature in the lower and middle layers accommodates more water vapor, which is not conducive to precipitation formation. Correspondingly, the Western Pacific Subtropical High at 500 hPa in the middle troposphere weakened. The low-level anticyclonic circulation at 850 hPa also weakened to the east, affecting water vapor transport in eastern China. It leads to a decrease in the water vapor transported northward by southeasterly from the western Pacific Ocean and a decrease in the water vapor flux reaching North China. This work indicates that accurate characterization of soil properties and snow cover on the TP is crucial for improving the simulation bias of summer rainfall in China.

Enhancing pool boiling in microgravity using micro-fins and an electrostatic field under different liquid subcooling

Despite boiling heat transfer is an effective way to remove heat and its performances comply with the high requirements of the electronics cooling and aerospace devices, in reduced gravity levels environments a decrease of the Critical Heat Flux (CHF) occurs. In the past decades, several techniques were developed to enhance the performances of a boiling system, such as external force fields and surface modification. Adding micro-structures on a boiling surface can delay the CHF occurrence, due to capillarity. As capillary forces are independent of gravity, this technique is potentially useful in microgravity. In the present study, micro-finned surfaces of new geometry were tested during parabolic flights in microgravity conditions under the action of an electric field and at different subcooling levels ranging from 5 to 35 K. The experimental results, reported here for the first time, showed that the micro-fins alone (whose characteristic length ranges from 30 to 120 µm) were not effective to increase CHF in microgravity, even if the heat transfer coefficients were higher with respect to the smooth surface tested for comparison. The addition of an external electric field enhanced the CHF due to its vapor removal capability and the bubble breaking effect. Moreover, the combined effect of micro-fins and electric field showed a synergic effect, increasing the CHF value up to 2.2 times. The CHF increased linearly with the subcooling level. The results indicate that micro-fins enhancing action can be severely reduced by the accumulation of vapor in the proximity of the surface, due to lack of buoyancy. However, if vapor is removed with an alternative action (e.g., electric forces) the fin enhancement is restored.

Spatial resolution effects on the solar open flux estimates

Context. Spectropolarimetric observations used to infer the solar magnetic fields are obtained with a limited spatial resolution. The effects of this limited resolution on the inference of the open flux over the observed region have not been extensively studied. Aims. We aim to characterize the biases that arise in the inference of the mean flux density by performing an end-to-end study that involves the generation of synthetic data, its interpretation (inversion), and a comparison of the results with the original model. Methods. We synthesized polarized spectra of the two magnetically sensitive lines of neutral iron around 630 nm from a state-of-the-art numerical simulation of the solar photosphere. We then performed data degradation to simulate the effect of the telescope with a limited angular resolution and interpreted (inverted) the data using a Milne-Eddington spectropolarimetric inversion code. We then studied the dependence of the inferred parameters on the telescope resolution. Results. The results show a significant decrease in the mean magnetic flux density – related to the open flux observed at the disk center – with decreasing telescope resolution. The original net magnetic field flux is fully resolved by a 1m telescope, but a 20 cm aperture telescope yields a 30% smaller value. Even in the fully resolved case, the result is still biased due to the corrugation of the photospheric surface. Conclusions. Even the spatially averaged quantities, such as the open magnetic flux in the observed region, are underestimated when the magnetic structures are unresolved. The reason for this is the presence of nonlinearities in the magnetic field inference process. This effect might have implications for the modeling of large-scale solar magnetic fields; for example, those corresponding to the coronal holes, or the polar magnetic fields, which are relevant to our understanding of the solar cycle.

Ending the prompt phase in photospheric models of gamma-ray bursts

The early steep decay, a rapid decrease in X-ray flux as a function of time following the prompt emission, is a robust feature seen in almost all gamma-ray bursts with early enough X-ray observations. This peculiar phenomenon has often been explained as emission from high latitudes of the last flashing shell. However, in photospheric models of gamma-ray bursts, the timescale of high-latitude emission is generally short compared to the duration of the steep decay phase, and hence an alternative explanation is needed. In this paper we show that the early steep decay can directly result from the final activity of the dying central engine. We find that the corresponding photospheric emission can reproduce both the temporal and spectral evolution observed. This requires a late-time behaviour that should be common to all gamma-ray burst central engines, and we estimate the necessary evolution of the kinetic power and the Lorentz factor. If this interpretation is correct, observation of the early steep decay can give us insights into the last stages of central activity, and provide new constraints on the late evolution of the Lorentz factor and photospheric radius.

Ultrafiltration polyanionic poly (3‐sulfopropyl methacrylate) membranes with enhanced antifouling and water flux

AbstractPolyethersulfone (PES) membranes are prevalent in the field of water treatment owing to their exceptional separation efficiency, robust mechanical properties, and resistance to chemical degradation. Nevertheless, these membranes are prone to fouling, resulting in a decrease in both flux and ultrafiltration efficiency. In the present study, PES membranes are blended with poly (3‐Sulfopropyl Methacrylate) (PSPMA) in various weight percentages (0%–3%) to improve their antifouling and ultrafiltration properties. The physicochemical properties of the blended membranes, including surface morphology, contact angle, hydrophilicity and surface energy are evaluated. The findings indicate that incorporation PSPMA results in an enhancement of the hydrophilic properties and surface charge of the PES membranes, assessed by employing Bovine Serum Albumin (BSA) as a representative protein. Modified blended membranes display greater Flux Recovery Ratio (FRR%) and exhibit superior fouling resistance. Under the same experimental conditions (0.2 MPa applied pressure), a pure water flux of 154.18 L·m−2·h−1 for PES/PSPMA membrane found substantially greater than pure PES membrane (103.52 L·m−2·h−1) along with Total Fouling Ratio (TFR) of 36% and 64.9% respectively. Exceptional antimicrobial efficacy for modified membranes is revealed against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) using disc diffusion technique rendering them well‐suited for water treatment applications.