Residual Content Research Articles

Effects of diamond as a main carbon source on the fabrication and mechanical properties of reaction-bonded SiC

RBSC with a low residual Si less than 5 vol% was fabricated using SiC–C preform with diamond as a main carbon source by a conventional reaction sintering process at the temperature range between 1500 °C and 1800 °C. The diamond content in the SiC–C preform varied from 10 wt% to 17 wt%. The diamond as the main carbon source used in SiC–C preform effectively minimized the residual Si in RBSC by increasing the reaction of diamond due to the enhanced Si melt infiltration even in SiC–C preform with high carbon content. The Si melt infiltration should be performed above 1600 °C for the complete reaction of diamond particles with size of 0.5 μm because of the relatively low dissolution rate of diamond in Si melt. The flexural strength of RBSC with residual Si content less than 7 vol% exceeded 400 MPa. The flexural strength of RBSC was increased with decreasing residual Si content, but sharply decreased by the residual carbon accompanying pores in RBSC. RBSC with low residual Si content displayed moderate flexural strengths around 200 MPa even above Si melt temperature because of the formation of continuous SiC structure in RBSC by the enhanced grain growth of SiC. Vickers hardness of RBSC was steadily increased from 17.7 GPa to 24.6 GPa with decreasing residual Si.

Cellulose acetate/chitosan composite film loaded with ground cinnamon for active packaging: water vapor sorption kinetic, compounds release, and antimicrobial effect

This study evaluated structural, physical, and water sorption properties of cellulose acetate/chitosan composite film incorporated with ground cinnamon as an antimicrobial. The controlled release of antimicrobial compounds and antimicrobial effects on Escherichia coli and Staphylococcus aureus were also monitored. The composite film formed highly porous and fibrous materials with higher thermal resistance. A higher ratio of chitosan in the film improved the swelling degree and water-vapor absorption capacity but reduced adsorption rates. Consequently, antimicrobial compounds, including eucalyptol, naphthalene, and β-caryophyllene, were more quickly released from the composite film with a larger chitosan ratio, affecting stronger antimicrobial effects. The inclusion of ground cinnamon with residual fat content in the film contributed to an extended inhibition of microbial growth in an indirect packaging system. Understanding the chitosan/cellulose acetate ratio in the film composite formation and the incorporation of ground cinnamon is important to control the compounds' release and generate long-term antimicrobial effects of active packaging materials on fresh food products.

Consumption of a Byproduct of Chia Seed Oil Extraction by Cold Pressing Ameliorates Cardiovascular Risks Factors in an Experimental Model of Metabolically Unhealthy Normal Weight.

The byproduct of Salvia hispanica (chia) seed oil extraction by cold pressing, also known as expeller, possesses a high nutritional value. It is rich in proteins, fibers, minerals, and has a residual oil content of 7-11%, which is rich in omega 3 linolenic acid (ALA). However, this byproduct has been historically undervalued. Thus, the aim of current work was to study the effects of consuming of a rich in chia expeller diet on a rabbit model of metabolically unhealthy normal weight to validate their use as a functional food. Rabbits were fed different diets for a period of 6 weeks: a standard diet (CD), a high-fat diet (HFD), a rich in expeller CD (Exp-CD) and a rich in expeller HFD (Exp-HFD). The Exp-HFD attenuated the rise in basal glucose, TyG index, triglycerides, cholesterol and non-HDL cholesterol induced by the HFD. Both rich in expeller diets reduced mean arterial blood pressure (MAP) and increase liver and fat ALA levels compared to their respective controls. Furthermore, the angiotensin converting enzyme (ACE) activity was lower in the lungs of animals fed on rich in expeller diets compared to their respective controls. In vitro studies showed that ALA inhibited ACE activity. The evaluation of vascular reactivity revealed that rich in expeller diets improved angiotensin II affinity and reduced contractile response to noradrenaline. In conclusion, the consumption of rich in expeller diets showed beneficial effects in preventing cardiovascular risk factors such as insulin resistance, dyslipidemia and MAP. Therefore, its use as functional ingredient holds significant promise.

Comparative Biological Half-Life of Penthiopyrad and Tebufenpyrad in Angelica Leaves and Establishment of Pre-Harvest Residue Limits (PHRLs).

To prevent pesticides from exceeding maximum residue limits (MRLs) in crops during export and shipment, it is necessary to manage residue levels during the pre-harvest stages. Therefore, the Republic of Korea establishes pre-harvest residue limits (PHRLs) per crop and pesticide. This study was conducted to set PHRLs for penthiopyrad and tebufenpyrad in angelica leaves, where the exceedance rates of MRLs are expected to be high. The LOQ of the analytical method used was 0.01 mg/kg and it demonstrated good linearity, with a correlation coefficient of 0.999 or higher within the quantitation range of 0.005 to 0.5 mg/kg. The recovery and storage stability accuracy values were in the range of 94.5-111.1%, within the acceptable range (70-120%, RSD ≤ 20%). The matrix effect for both pesticides was in the medium-to-strong range, and it did not significantly impact the quantitative results as a matrix-matched calibration method was employed. Using the validated method, residue concentrations of penthiopyrad 20 (%) EC and tebufenpyrad 10 (%) EC were analyzed. Both pesticides exhibited a decreasing residue trend over time. In Fields 1-3 and their integrated results, the biological half-life was within 2.6-4.0 days for penthiopyrad and 3.0-4.2 days for tebufenpyrad. The minimum value of the regression coefficient in the dissipation curve regression equation was selected as the dissipation constant. The selected dissipation constants for penthiopyrad in Fields 1-3 and their integration were 0.1221, 0.2081, 0.2162, and 0.1960. For tebufenpyrad, the dissipation constants were 0.1451, 0.0960, 0.1725, and 0.1600, respectively. The dissipation constant was used to calculate PHRL per field. Following the principles of the PHRL proposal process, residue levels (%) on PHI dates relative to MRLs were calculated, and fields for proposing PHRLs were selected. For penthiopyrad, since the residue level (%) was less than 20%, the PHRL for Field 3 with the largest dissipation constant was proposed. For tebufenpyrad, as the residue level (%) exceeded 80%, the PHRL proposal could not established. It is deemed necessary to reassess the MRL and 'guidelines for safe use' for tebufenpyrad in angelica leaves.

Dynamic Behavior of Systemic Insecticide Residues in Snapdragons

Pesticide application is used in horticulture to reduce plant damage from organisms such as insects and mites. Systemic insecticides are highly efficacious and readily taken up by plant tissues. However, pesticide-treated plants may impose risks to nontarget insects or other organisms within ecosystems. In this study, insecticide residues in nectar, leaves, and flower petals of the horticulturally significant herbaceous annual snapdragon, Antirrhinum majus (Lamiales: Plantaginaceae), were assessed at two locations over several weeks following foliar and drench treatment with five systemic insecticides. Concentrations of the insecticides were determined by liquid chromatography–mass spectrometry. The independent effects Application Method, Application Rate, and Time were statistically significant among all active ingredients in the three matrices in both sites in California (CA) and New Jersey (NJ). The interaction effects were also generally statistically significant in the CA site but less consistently so in the NJ site, dependent on the active ingredient and matrix. Post hoc analyses found the highest residue concentrations in leaves and the lowest in nectar, a trend generally consistent over time regardless of active ingredient for both the CA and NJ sites. The results of this study are discussed in the context of conserving pollinators and other beneficial insects. It is recommended that similar studies should be implemented in different geographical regions and climates, along with multiyear studies for perennial ornamental plants.

Responses of Soil Carbon and Microbial Residues to Degradation in Moso Bamboo Forest.

Moso bamboo (Phyllostachys heterocycla cv. Pubescens) is known for its high capacity to sequester atmospheric carbon (C), which has a unique role to play in the fight against global warming. However, due to rising labor costs and falling bamboo prices, many Moso bamboo forests are shifting to an extensive management model without fertilization, resulting in gradual degradation of Moso bamboo forests. However, many Moso bamboo forests are being degraded due to rising labor costs and declining bamboo timber prices. To delineate the effect of degradation on soil microbial carbon sequestration, we instituted a rigorous analysis of Moso bamboo forests subjected to different degradation durations, namely: continuous management (CK), 5 years of degradation (D-5), and 10 years of degradation (D-10). Our inquiry encompassed soil strata at 0-20 cm and 20-40 cm, scrutinizing alterations in soil organic carbon(SOC), water-soluble carbon(WSOC), microbial carbon(MBC)and microbial residues. We discerned a positive correlation between degradation and augmented levels of SOC, WSOC, and MBC across both strata. Furthermore, degradation escalated concentrations of specific soil amino sugars and microbial residues. Intriguingly, extended degradation diminished the proportional contribution of microbial residuals to SOC, implying a possible decline in microbial activity longitudinally. These findings offer a detailed insight into microbial C processes within degraded bamboo ecosystems.

Enhancing interlayer bonding strength of 3D printed ternary geopolymer using calcium carbonate whiskers spray

Weak interlayer bonding, especially induced by a long period of printing interruption, is one of the major concerns for 3D printing concrete. The effect of CaCO3 whiskers suspension (CWS) spray and printing time interval on the interlayer bonding of 3D printing fly ash-granulated blast furnace slag-steel slag based geopolymer was investigated with splitting tensile strength and direct shear strength tests. The underlying mechanisms were explored based on the characterization of micromorphology, porosity, surface roughness and reaction kinetics of interlayer area. It was revealed that the CWS spray at appropriate concentrations can significantly improve the interlayer bonding of geopolymer printed at extended printing intervals, with 0.05 g/mL of CWS increasing the shear strength up to 71% at 60 min and 0.10 g/mL of CWS increasing the splitting tensile strength by 40% at 40 min. The CWS at proper concentrations could replenish the interlayer moisture, fill the interlayer voids and provide nucleation sites for geopolymerization and hydration products, i.e., N(C)-A-S-H and C-S-H gels. However, excessive CaCO3 whiskers or water content was harmful to the interlayer bonding. As the reaction process and microstructure of 3D printed ternary geopolymer were synergistically impacted by the printing time interval, residual water content, compensated moisture and CaCO3 whisker reinforcement, the mix of CWS spray should be carefully designed to optimize its effectiveness on the interlayer strengthening.

Following Regulation, Imidacloprid Persists and Flupyradifurone Increases in Nontarget Wildlife.

After regulation of pesticides, determination of their persistence in the environment is an important indicator of effectiveness of these measures. We quantified concentrations of two types of systemic insecticides, neonicotinoids (imidacloprid, acetamiprid, clothianidin, thiacloprid, and thiamethoxam) and butenolides (flupyradifurone), in off-crop nontarget media of hummingbird cloacal fluid, honey bee (Apis mellifera) nectar and honey, and wildflowers before and after regulation of imidacloprid on highbush blueberries in Canada in April 2021. We found that mean total pesticide load increased in hummingbird cloacal fluid, nectar, and flower samples following imidacloprid regulation. On average, we did not find evidence of a decrease in imidacloprid concentrations after regulation. However, there were some decreases, some increases, and other cases with no changes in imidacloprid levels depending on the specific media, time point of sampling, and site type. At the same time, we found an overall increase in flupyradifurone, acetamiprid, thiamethoxam, and thiacloprid but no change in clothianidin concentrations. In particular, flupyradifurone concentrations observed in biota sampled near agricultural areas increased twofold in honey bee nectar, sevenfold in hummingbird cloacal fluid, and eightfold in flowers after the 2021 imidacloprid regulation. The highest residue detected was flupyradifurone at 665 ng/mL (parts per billion [ppb]) in honey bee nectar. Mean total pesticide loads were highest in honey samples (84 ± 10 ppb), followed by nectar (56 ± 7 ppb), then hummingbird cloacal fluid (1.8 ± 0.5 ppb), and least, flowers (0.51 ± 0.06 ppb). Our results highlight that limited regulation of imidacloprid does not immediately reduce residue concentrations, while other systemic insecticides, possibly replacement compounds, concurrently increase in wildlife. Environ Toxicol Chem 2024;43:1497-1508. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Underestimation of carbon dioxide emissions from organic-rich agricultural soils

Organic-rich agricultural soils, including drained peatlands, are hotspots for biogenic CO2 emissions. Due to microbial mineralisation, the organic carbon (OC) content of these soils transitions to that of mineral soils, but it remains unclear how the residual OC content controls the rate of CO2 emission. Here we show that area-scaled CO2 emissions from topsoils with >6% OC are not controlled by OC content and OC density in a comprehensive laboratory incubation experiment. National greenhouse gas inventories assign area-scaled CO2 emission factors to soils with >12% OC, while soils with 6-12% OC are mostly disregarded or treated with lower emission factors. In this respect, our results suggest that CO2 emissions from organic soils could be underestimated by up to 40% in the Danish national inventory submission to the United Nations Framework Convention on Climate Change (UNFCCC). We conclude that global underestimation of area-scaled CO2 emissions from 6-12% OC soils occurs in countries with large proportions of organic soils in transition from organic to organo-mineral soils due to agricultural management. Refining CO2 emission estimates for 6-12% OC soils is critical for the accuracy of national inventories, but also for recognising the climate benefits of initiatives to rewet drained organic soils.

Synthesis of a novel Si-N-S flame retardant and its application on cotton cellulose biomacromolecule

A novel flame retardant containing Si, N, and S elements, ((2-(triethoxysilyl)ethyl)thio)ethan-1-amine hydrochloride (TETEA), was synthesized via a click reaction and characterized using nuclear magnetic resonance spectroscopy (NMR) and fourier transform infrared spectroscopy (FTIR). Subsequently, the flame-retardant cotton fabric was fabricated by sol-gel method. The results indicated that TETEA was successfully loaded on cotton fabric and formed a uniform protective layer on the surface of cotton fabric, exhibiting excellent flame retardancy. The flame-retardant cotton fabric achieved limiting oxygen index (LOI) of 28.3 % and passed vertical combustion test without after-flame or afterglow time at TETEA concentration of 500 g/L. Thermogravimetric analysis revealed that the residual carbon content of the flame-retardant cotton fabric was much higher than that of the control under air and N2 conditions. Besides, the flame-retardant cotton fabric was not ignited in cone calorimeter test with an external heat flux of 35 kW/m2. The peak heat release rate and the total heat release decreased from 133.4 kW/m2 to 25.8 kW/m2 and from 26.46 MJ/m2 to 17.96 MJ/m2, respectively. This phosphorus-free flame retardant offers a simplified synthesis process without adverse environmental impacts, opening up a new avenue for the development environmentally friendly flame retardants compared to traditional alternatives.

Hybrid Alloyed Sinter Hardening Steels Based on Different Prealloyed Powders

Abstract Sinter hardening grade steels were prepared using hybrid alloying by combining Cr-Mo and Mo prealloyed powders with fine Mn-Si masteralloy powders. Compacts from both base powders showed the “internal getter” effect, which however was much more pronounced for the Cr-Mo powders because of the markedly high starting oxygen content. Combining the base powders with the masteralloy resulted in the desired sinter hardenability, the Mo prealloyed powder resulting in somewhat better properties because of more complete dissolution of the masteralloy and lower residual oxygen content.

Cranial trauma in handgun executions: Circumferential delamination defect and its relationship with contact/close-range shooting.

Skeletal evidence usually constitutes the only source of information to interpret lesion patterns that help to clarify the circumstances surrounding death. The examination and interpretation of bone trauma are essential to the application and utility of anthropology as a forensic science. When discussing the effect of gunshot wounds in bone, it becomes imperative to differentiate between short and long-distance injuries based on clear, distinct, and observable signs. To contribute to the debate, our focus is directed toward the external analysis of the so-called circumferential delamination defect (CDD) as an observable proxy for close-range shooting (≤30 cm) and contact gunshot wounds in the skull. In the context of known extrajudicial killings, in which the perpetrators used short 9 × 19 FMJ ammunition in a close-range shooting, instances of CDD have been documented. Empirical evidence reinforcing the causal relationship between CDD and close-range shootings is presented. Elements' characteristics of firearm residues were also found in remains buried for up to 30 years. Primarily, this work shows that the concentrations of gunshot residues (Pb, Ba, and Sb) resemble those observed in fresh corpses with the same gunshot wound (GSW). Moreover, the correlation observed between CDD and gunshot residues, where the likelihood of CDD increases the closer to the head and the more perpendicular the shot angle is, reinforces CDD as a pivotal discriminatory factor in the skeletal evidence of short-range or contact shot. This research contributes to the field of forensic anthropology by providing fundamental insights into the etiology of CDD and its practical application.

Effects of washing with boric acid solutions on residual boric acid content, microbiological load, and quality of fresh-cut spinach

Insufficient disinfection of fresh-cut spinach poses significant health risks, along with potential issues like odor, color changes, and softening during short-term storage. To address these challenges, boric acid solutions were explored as an alternative to chlorine washes, which are known to produce toxic compounds. Among various concentrations, 1 % boric acid exhibited the most effective microbial inactivation, leading to substantial reductions in total mesophilic aerobic bacteria, total yeast and mold, and Enterobacteriaceae counts, with reductions of 1.64, 1.38, and 1.77 logs, respectively. Additionally, washing spinach leaves with this solution for 1 min maintained quality parameters, with enhanced antioxidant activity (55.26 mg kg−1 Trolox equivalent), increased total phenolic content (1214.06 mg kg−1 gallic acid equivalent), retention of chlorophyll a (839.16 mg kg−1), chlorophyll b (539.61 mg kg−1) and ascorbic acid content (264.72 mg kg−1). Mechanical properties such as puncture strength (1.81 N) and puncture distance (52.78 mm) also showed favorable outcomes, alongside optimal moisture content at 89.81 %. Notably, residual boric acid content was lowest in spinach leaves (1252.49 mg kg−1) and highest in the wash water (53.88 mg kg−1) after treatment. Scanning electron microscopy images demonstrated maintained tissue integrity, while Hunter Lab readings indicated minimal color changes post-washing. Additionally, sensory evaluations and various physicochemical analyses further supported the efficacy of boric acid washing. Consequently, washing spinach leaves with a 1 % boric acid solution for 1 min yielded favorable results across multiple quality parameters. These findings suggest the potential of boric acid as a safe and effective alternative disinfectant in the fresh-cut produce industry, highlighting its practical implications for food safety and quality. Future research should focus on exploring long-term effects and optimizing washing protocols for broader applications.

Water–ice phase transition in frozen soils: a mesoscopic numerical study based on lattice Boltzmann method

ABSTRACT The phenomenon of water–ice phase transition in frozen soils is the key to explaining the mechanism of frost heaving and thawing settlement disaster. However, numerical analysis of water–ice phase transitions in frozen soils at mesoscale is rarely reported. This study combines the modified Gibbs-Thomson equation and the enthalpy-based lattice Boltzmann model, and develops a mesoscale numerical method to simulate the water–ice phase transition in the local pores of saturated frozen soil during freezing and thawing process. In order to accurately simulate this process, a new η coefficient is proposed to modify the Gibbs-Thomson equation, which is unrelated to the type of soil sample and gradation characteristics. According to the particle size distribution curve, the two-dimensional random circle generation method is used to reconstruct the soil pore structure. The freezing and thawing processes are verified with the experimental data. A larger non-uniformity coefficient C u and curvature coefficient C c of the grain size distribution result in a lower degree of subcooling and lower residual water content of the soil during the freezing process. The new model provides an effective means to understand the water–ice phase transition in frozen soil at a mesoscopic scale.

Exploring the Biogenic Transformation Mechanism of Polyphenols by Lactobacillus plantarum NCU137 Fermentation and Its Enhancement of Antioxidant Properties in Wolfberry Juice.

This study investigated the transformation of polyphenols, including free and bound polyphenols during the fermentation of wolfberry juice by Lactobacillus plantarum NCU137. Results indicated that fermentation significantly increased the free polyphenols content and released bound polyphenols, enhancing the antioxidant activity. Analysis showed that there were 19 free polyphenols, mainly scopoletin, pyrogallol, and dihydroferulic acid, and 16 bound polyphenols, especially p-coumaric acid, feruloyl hexoside, and caffeic acid. A significant correlation was observed between the generation and degradation of polyphenols, and specific bound polyphenols peaked during the 24-48 h fermentation. Furthermore, reduced surface roughness and galacturonic acid content in wolfberry residue, along with increased pectinase activity, suggested substantial pectin degradation in the cell wall, which may be associated with the release of polyphenols, due to pectin serving as carriers for bound polyphenols. The fermentation also increased polyphenol oxidase and peroxidase activity, contributing to polyphenol breakdown. These findings provide insights for improving wolfberry juice production.

MONITORING OF PESTICIDE RESIDUES IN GRAPEVINE LEAVES UNDER VARIANT FUNGAL DISEASE MANAGEMENT

Food contamination is the result of over-reliance on fungicides in crop production. The presence of pesticide residues in agricultural commodities needs to be strategically solved by applying gentle agrotechnical procedures. The research aimed to evaluate the effect of the treatment of grapevine with fungicides on the content and mobility of 4 active substances in the leaves of the variety Hibernal. The experiment included a control variant treated with fungicides and an untreated variant. We focused on monitoring the active substances of fungicides used in the first half of the vegetation: azoxystrobin, cyflufenamid, difenoconazole, myclobutanil, and another 25 active substances, in terms of multi-residue analysis methodologies. Grape leaves for analysis were collected on two dates: in the phenological phase of berry development BBCH 73 and 14 days after grape harvest – BBCH 91. Samples were prepared according to STN EN 15662. For qualitative analyzes of residues, we used the QuEChERS method in combination with liquid (LC-MS/MS) and gas (GC-MS/MS) chromatography with tandem mass spectrometry. In the untreated variant, the contents of residues from both leaves collection were in undetectable values. In the leaf samples of the treated variant collected in BBCH 73, we established higher values of residues than the MRL determines, namely for azoxystrobin 0.083 mg/kg (MRL – 0.01 mg/kg). Azoxystrobin is the active substance of the Quadris max fungicide, and we applied this preparation 41 days before the first collection of leaves. In the analyzes of leaf sampling from the treated variant after grape harvest in BBCH 91, we found a decrease in the content of all monitored residues below detectable values. We consider the gradual degradation of residues in biological materials to be a very favorable result from the point of view of their impact on consumer health and the environment. Through visual observations of the vegetation, we found out that even the untreated variant had a perfect state of health. Hibernal is a variety suitable for biological production systems, and we assume that even in vintages with high pressure of fungal diseases, it is possible to maintain the health of the grapevine with ecological products. Using the appropriate grape variety combined with the right agrotechnical interventions makes it possible to use safer ecological practices to produce healthy food, maintaining sustainability and a healthy natural environment. The research will continue in the early Table grape varieties, where the vegetation period is shorter, and space for breaking down the residues is more difficult.

Study on the water retention curve of shredded municipal solid waste considering the compressibility of specimens based on the centrifuge method.

The water retention curve (WRC) of municipal solid waste (MSW) is the important hydraulic parameter for the study of unsaturated seepage analysis in landfills. Due to the compressibility and degradability of the waste, the search for a method to quickly and accurately test its water retention curve (WRC) is a current problem that needs to be solved. In this paper, considering the volume change of the waste specimens in test, the test principle of centrifuge testing of WRC is corrected to make it applicable to the testing of waste WRC. In addition, the WRCs of 20 MSW specimens with typical landfill compositions and porosities are measured using the corrected centrifuge test. The effects of compositions and porosities of waste specimens on WRC parameters were analyzed. The results are summarized as follows. Disregarding the height reduction of specimens resulted in overestimated matric suction values and underestimating volume water content values. By comparing uncorrected and corrected values, the maximum difference of the matric suction and volumetric water content reach 233kPa and 11%, respectively. This study can provide a reference for accurately measuring the WRC of MSW using a centrifuge. For the waste specimen without kitchen and yard waste, composition had less of an effect on the WRC of waste compared to porosity. The effect of the content of the non-absorbable fraction on the residual volumetric water content θr and the parameter nv in the van Genuchten model was significant. The initial porosity n had a great effect on the parameter α.

Selective adsorption and separation of salicylic acid and 4‐hydroxyisophthalic acid from industry‐grade 4‐hydroxybenzoic acid on UiO‐66

AbstractIn this study, UiO‐66 was employed for the first time as an adsorbent to separate phenolic acid analogues, specifically 4‐hydroxyisophthalic acid and salicylic acid, from impurities. Synthesized in‐house, UiO‐66 was shown to exhibit high selectivity towards 4‐HIPA/4‐HBA and SA/4‐HBA when a molar equivalent of acetic acid modulator to terephthalic acid was set at 44. The adsorption capacities for 4‐HBA, 4‐HIPA, and SA were determined to be 56.34, 55.02, and 60.34 mg/g, respectively. Furthermore, it was observed that after six regeneration cycles, the adsorption capacity for 4‐HBA remained nearly unchanged, whereas those for 4‐HIPA and SA decreased by 5.6% and 2.6%, respectively. FTIR and XPS analyses revealed that all three compounds were adsorbed at the same dominant Zr cluster site on UiO‐66, primarily through hydrogen bonding and electrostatic interaction. Dynamic adsorption experiments revealed that 4‐HBA was the first to elute, maintaining the residual contents of 4‐HIPA and SA below 0.1 wt%. Compared to traditional separation techniques, this paper provided a simple and effective method to purify industrial grade 4‐hydroxybenzoic acid.

Microbial preference for chlorate over perchlorate under simulated shallow subsurface Mars-like conditions

The Martian surface and shallow subsurface lacks stable liquid water, yet hygroscopic salts in the regolith may enable the transient formation of liquid brines. This study investigated the combined impact of water scarcity, UV exposure, and regolith depth on microbial survival under Mars-like environmental conditions. Both vegetative cells of Debaryomyces hansenii and Planococcus halocryophilus, alongside with spores of Aspergillus niger, were exposed to an experimental chamber simulating Martian environmental conditions (constant temperatures of about − 11 °C, low pressure of approximately 6 mbar, a CO2 atmosphere, and 2 h of daily UV irradiation). We evaluated colony-forming units (CFU) and water content at three different regolith depths before and after exposure periods of 3 and 7 days, respectively. Each organism was tested under three conditions: one without the addition of salts to the regolith, one containing sodium chlorate, and one with sodium perchlorate. Our results reveal that the residual water content after the exposure experiments increased with regolith depth, along with the organism survival rates in chlorate-containing and salt-free samples. The survival rates of the three organisms in perchlorate-containing regolith were consistently lower for all organisms and depths compared to chlorate, with the most significant difference being observed at a depth of 10–12 cm, which corresponds to the depth with the highest residual water content. The postulated reason for this is an increase in the salt concentration at this depth due to the freezing of water, showing that for these organisms, perchlorate brines are more toxic than chlorate brines under the experimental conditions. This underscores the significance of chlorate salts when considering the habitability of Martian environments.

Effect of residual carbon on silicon carbide ceramics in photopolymerization-based additive manufacturing

Silicon carbide (SiC) is widely used in various industrial fields for its excellent properties. Vat photopolymerization (VP) technology stands out in the fabrication of SiC ceramics due to its enhanced design flexibility and capability to produce intricate geometries. However, the excessive residual carbon content in VP technology directly affects the sintering performance of SiC ceramics, leading to cracking and deformation defects. To address this issue, we systematically studied the residual carbon content of SiC under different debinding atmospheres in forming by VP technology. We found that the debinding atmosphere can effectively control the residual carbon content in SiC ceramics. Residual carbon exists in samples with a lower degree of defect, promotes grain growth, reduces neck size, and results in flexural strength of 253.13 MPa after pressureless sintering. This research promotes the application of VP technology in SiC ceramics and opens up a new avenue for the development of high-performance SiC ceramics.