Effects of Heating Treatment on the Physicochemical and Volatile Flavor Properties of Argentinian Shortfin Squid (Illex argentinus).

In this study, the effect of different heating temperatures (80, 90, 100, and 121 °C) on the physicochemical and volatile flavor properties of fried mantles (Argentinian shortfin) was investigated. The squid mantles were soaked in a maltose syrup solution (20% w/v) for 10 s and fried in soybean oil for 10 s (160 °C), vacuum-packed, and processed at different temperatures for 10 min. Then, the squid mantles were subjected to colorimetric analysis, sensory evaluation, free amino acid analysis, and texture profile analysis. In addition, the volatile organic compounds (VOCs) in the squid mantles were analyzed. The results revealed that lower treating temperatures (80 and 90 °C) improved the chromatic and textural properties, along with organoleptic perception. Additionally, the content of amino acid in the squid mantles treated at 121 °C was significantly lower than that of the samples treated at other temperatures (p < 0.05). Headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) was used to detect 41 VOCs, including their monomers and dimers. Among these detected VOCs, the contents of alcohols, ketones, and pyrazines were positively correlated with temperature. However, the content of aldehydes in the squid mantles gradually decreased as the heating temperature increased (p < 0.05). The combined HS-GC-IMS and E-nose results revealed that the lower temperatures (80 and 90 °C) were more suitable for flavor development and practical processing. This study provides valuable information for properly controlling the heating process of squid products, as well as flavor and practical applications for the aquatic industry.

Role of volcanism and impact heating in mass extinction climate shifts.

This study investigates the mechanisms underlying the varied climate changes witnessed during mass extinctions in the Phanerozoic Eon. Climate shifts during mass extinctions have manifested as either predominant global cooling or predominant warming, yet the causes behind these occurrences remain unclear. We emphasize the significance of sedimentary rock temperature in comprehending these climate shifts. Our research reveals that low-temperature heating of sulfide leads to global cooling through the release of sulfur dioxide (SO2), while intermediate-temperature heating of hydrocarbons and carbonates releases substantial carbon dioxide (CO2), contributing to global warming. High-temperature heating additionally generates SO2 from sulfate, further contributing to global cooling. Different degrees of contact heating of the host rock can lead to different dominant volatile gas emissions, crucially driving either warming or cooling. Moreover, medium to high-temperature shock-heating resulting from asteroid impacts produces soot from hydrocarbons, also contributing to global cooling. Large-scale volcanic activity and asteroid impacts are both events that heat rocks, emitting the same gases and particles, causing climate changes. The findings elucidate the critical role of heating temperature and heating time in understanding major climate changes during mass extinctions.

Important roles of coarse particles in pasting and gelling performance of different pulse flours under high-temperature heating.

Dehulled pea, lentil, and faba bean grains were milled into flours with 0.5- to 2.5-mm sieves. As the particle size decreased, damaged-starch contents of the flours from the same pulse crop increased. At a holding temperature of 95 °C in RVA, peak and final viscosities and gelling ability of the flours generally increased as the particle size decreased. When the holding temperature increased from 95 to 140 °C, pasting viscosities of pea and lentil flours and gel hardness of lentil flours gradually decreased. In contrast, pasting viscosities and gel hardness of faba bean flours reached the highest values at 120 °C. The comparison of the pulse flours varying in particle size across the three market classes revealed that coarse particles comprising agglomerated starch, protein, and dietary fiber (i.e., particles of the second peak in the bimodal particle-size distribution curves) showed significant correlations with certain important functional properties of pulse flours.

Prompt Electronic Discrimination of Gas Molecules by Self-Heating Temperature Modulation.

Though considerable progress has been achieved on gas molecule recognition by electronic nose (e-nose) comprised of nonselective (metal oxide) semiconductor chemiresistors, extracting adequate molecular features within short time (<1 s) remains a big obstacle, which hinders the emerging e-nose applications in lethal or explosive gas warning. Herein, by virtue of the ultrafast (∼20 µs) thermal relaxation time of self-heated WO3-based chemiresistors fabricated via oblique angle deposition, instead of external heating, self-heating temperature modulation has been proposed to generate sufficient electrical response features. Accurate discrimination of 12 gases (including 3 xylene isomers with the same function group and molecular weight) has been readily achieved within 0.5-1 s, which is one order faster than the state-of-the-art e-noses. A smart wireless e-nose, capable of instantaneously discriminating target gas in ambient air background, has been developed, paving the way for the practical applications of e-nose in the area of homeland security and public health.

Temperature Thresholds of Pyrogenic Dissolved Organic Matter in Heating Experiments Simulating Forest Fires.

Heating temperature (HT) during forest fires is a critical factor in regulating the quantity and quality of pyrogenic dissolved organic matter (DOM). However, the temperature thresholds at which maximum amounts of DOM are produced (TTmax) and at which the DOC gain turns into net DOC loss (TT0) remain unidentified on a component-specific basis. Here, based on solid-state 13C nuclear magnetic resonance, absorbance and fluorescence spectroscopies, and Fourier transform ion cyclotron resonance mass spectrometry, we analyzed variations in DOM composition in detritus and soil with HT (150-500 °C) and identified temperature thresholds for components on structural, fluorophoric, and molecular formula levels. TTmax was similar for detritus and soil and ranged between 225 and 250 °C for bulk dissolved organic carbon (DOC) and most DOM components. TT0 was consistently lower in detritus than in soil. Moreover, temperature thresholds differed across the DOM components. As the HT increased, net loss was observed initially in molecular formulas tentatively associated with carbohydrates and aliphatics, then proteins, peptides, and polyphenolics, and ultimately condensed aromatics. Notably, at temperatures lower than TT0, particularly at TTmax, burning increased the DOC quantity and thus might increase labile substrates to fuel soil microbial community. These composition-specific variations of DOM with temperature imply nonlinear and multiple temperature-dependent wildfire impacts on soil organic matter properties.

Combined effect of heating temperature and content of pectin on the textural properties, rheology, and 3D printability of potato starch gel.

Three-dimensional (3D) printing is one of the emerging techniques which fabricates customized foods with desired sensory characteristics. Rheological properties of 3D printing materials are vitally important in printability which govern the flowability and structural stability. Due to its unique gel-forming characteristics, potato starch has been extensively used in myriad food applications, such as 3D printing. However, little attention has been paid to the combined effect of heating temperature and pectin addition on the properties of potato starch gels. Thus, this study investigated the impact of different pectin contents (1, 1.5, and 2 %) on printability and the rheological and textural properties of potato starch gels heated at different temperatures (70, 80, and 90 °C). The gel heating temperature governs pectin-driven modifications in potato starch gels. Pectin addition increased the 3D printability, viscosity, storage modulus, hardness, gumminess, and springiness of starch gel at higher temperatures (80 °C and 90 °C). In contrast, at lower temperatures (70 °C), pectin addition decreased printability, viscosity, storage modulus, hardness, gumminess, and springiness. Therefore, the gel heating temperature influences the impact of pectin on printability, rheology, and textural properties. Accordingly, the combined effects of pectin and heating temperature should be considered in pectin-based 3D food-printing ink formulations.

Heating temperatures affect meat quality and vibrational spectroscopic properties of slow- and fast-growing chickens.

This study determined the effect of water bath cooking (70°C and 90°C for 40 min) and the extreme heat treatment by an autoclave (121°C for 40 min) on the quality of breast meat of a fast-growing chicken, commercial broiler (CB), and slow-growing chickens, Korat chicken (KC), and Thai native chicken (NC) (Leung Hang Khao), by vibrational spectroscopic techniques, including synchrotron radiation-based Fourier transform infrared (SR-FTIR) microspectroscopy and Fourier transform Raman (FT-Raman) spectroscopy. Taste-enhancing compounds, including inosine-5'-monophosphate (IMP) and guanosine-5'-monophosphate (GMP), were better retained in cooked KC and NC meats than in cooked CB meat (P < 0.05). The high heat treatment at 121°C depleted the amount of insoluble collagen in all breeds (P < 0.05). Shear force values of slow-growing chicken meat were not affected by high heating temperatures (P > 0.05). In addition, the high heat treatment increased protein carbonyl (P < 0.05), while no effect on in vitro protein digestibility (P > 0.05). SR-FTIR microspectroscopy performed better in differentiating the meat quality of different chicken breeds, whereas FT-Raman spectroscopy clearly revealed differences in meat qualities induced by heating temperature. Based on principal component analysis (PCA), distinct characteristics of chicken meat cooked at 70°C were high water-holding capacity, lightness (L*), moisture content, and predominant α-helix structure, correlating with Raman spectra at 3,217 cm-1 (O-H stretching of water) and 1,651 cm-1 (amide I; α-helix). The high heating temperature at 90°C and 121°C exposed protein structure to a greater extent, as evidenced by an increase in ß-sheets, which was well correlated with the Raman spectra at 2,968 and 2,893 cm-1 (C-H stretching), tryptophan (880 cm-1), tyrosine (858 cm-1), and 1,042, 1,020, and 990 cm-1 (C-C stretching; ß-sheet). SR-FTIR and FT-Raman spectroscopy show potential for differentiation of chicken meat quality with respect to breeds and cooking temperatures. The marked differences in wavenumbers would be beneficial as markers for determining the quality of cooked meats from slow- and fast-growing chickens.

Effect of Various Dynamic Shear Rheometer Testing Methods on the Measured Rheological Properties of Bitumen.

A 23 factorial design experiment was conducted to study the influence of pre-heating temperature (HT) for manufacturing sample, bonding temperature (BT) onto rheometer, and trimming state (Trim) of the sample on complex shear modulus (G*) and phase angle (δ) using a dynamic shear rheometer on unmodified bitumen of types 50/70, 70/100, and two 160/220 from various sources. In addition, the black diagram and 2S2P1D model were used to evaluate the viscoelastic properties of bitumens. Findings show that the G* is more sensitive to the changes than the δ. Additionally, it was found that the 8 mm parallel plate diameter had a higher sensitivity to the trimming state than the 25 mm. The tested factor HT generally did not have a statistically significant impact on the results of the tested materials, except for 160/220_I. At practically all the temperatures tested for 50/70 and 160/220_II, the G* dropped by increasing the factor BT from a lower to a higher value. The Trim:BT interaction has the greatest impact on all materials and temperatures on G*, except for 160/220 at lower temperatures. However, in the case of δ, the Trim:BT interaction has the most significant effects for 70/100 and 160/220_II. The black diagrams show no discernible differences, which may be a result of the limited range of changes made to the variables.

Exploring in vitro gastrointestinal digestion of myofibrillar proteins at different heating temperatures.

The effects of different heating temperatures (40-115 °C) on the structure, oxidation, and digestibility of beef myofibrillar protein were investigated. Reductions in the number of sulfhydryl groups were observed, together with gradual increases in the number of carbonyl groups, indicating oxidation of the protein by the increased temperatures. At temperatures between 40 °C and 85 °C, ß-sheets were converted to α-helices, and increased surface hydrophobicity showed that the protein expanded as the temperature approached 85 °C. These changes were reversed at temperatures over 85 °C, indicative of aggregation induced by thermal oxidation. Between 40 °C and 85 °C, the digestibility of the myofibrillar protein was increased, reaching a maximum of 59.5 % at 85 °C, after which it began to decrease. These results indicated that moderate heating and oxidation-induced protein expansion were beneficial to digestion while protein aggregation resulting from excessive heating is not conducive to digestion.

Epidemiological characteristics of Cox A6 infected with hand-foot-mouth disease in children aged 1-12 years in Enshi / 公共卫生与预防医学

Objective To investigate the incidence and risk factors of severe cases of Cox A6 infected with HAND-foot-mouth disease in 1-12 years old children in Enshi city, and to provide reference for prevention and treatment of hand-foot-mouth disease. Methods From January to September 2021, hospitalized children aged 1-12 years with HFMD in Enshi city were collected. The samples of anal swabs and throat swabs were tested for Coxsackie virus A6 (Cox A6) nucleic acid, and the distribution of Cox A6 patients infected with HFMD and the proportion of severe cases in children aged 1-12 years were analyzed. Logistic regression was used to analyze the risk factors of severe cases. Results From January to September 2021, a total of 343 HFMD cases aged 1 to 12 years were reported in Enshi, among which 241 cases (70.26%) were infected with CoxA6. No death cases were reported during the period. The 241 cases of Cox A6 infected with HFMD were distributed from January to September. 129 males (53.53%) and 112 females (46.47%); 208 cases (44.40%) were mainly from 1 to 3 years old, followed by 66 cases (28.39%) from 4 to 6 years old, 45 cases (18.67%) from 7 to 9 years old, and 23 cases (9.54%) from 10 to 12 years old. Cox A6 was mainly infected with HFMD in 145 cases (60.17%) in rural areas and 96 cases (39.83%) in urban areas. 10 cases (4.15%) of Cox A6 infected HFMD were severe cases; There were significant differences in age, fever temperature, fasting blood glucose and fever time between the severe case group and the normal case group (P<0.05). Logistic multivariate regression analysis showed that fever temperature (OR=1.559, P<0.05), fasting blood glucose (OR=2.472, P<0.05) and fever time (OR=2.932, P<0.05) were independent risk factors for the occurrence of severe cases of Cox A6 infected with HFMWD in Enshi. Conclusion The incidence of Cox A6 infected with HFMD in Enshi is mainly concentrated in boys under 3 years old. Clinical treatment of HFMD children should focus on children with high fever temperature, fasting blood glucose and long fever time.

Investigation of Structural, Morphological and Magnetic Properties of MFe2O4 (M = Co, Ni, Zn, Cu, Mn) Obtained by Thermal Decomposition.

The structural, morphological and magnetic properties of MFe2O4 (M = Co, Ni, Zn, Cu, Mn) type ferrites produced by thermal decomposition at 700 and 1000 °C were studied. The thermal analysis revealed that the ferrites are formed at up to 350 °C. After heat treatment at 1000 °C, single-phase ferrite nanoparticles were attained, while after heat treatment at 700 °C, the CoFe2O4 was accompanied by Co3O4 and the MnFe2O4 by α-Fe2O3. The particle size of the spherical shape in the nanoscale region was confirmed by transmission electron microscopy. The specific surface area below 0.5 m2/g suggested a non-porous structure with particle agglomeration that limits nitrogen absorption. By heat treatment at 1000 °C, superparamagnetic CoFe2O4 nanoparticles and paramagnetic NiFe2O4, MnFe2O4, CuFe2O4 and ZnFe2O4 nanoparticles were obtained.

Investigating the Potential Plasticizing Effect of Di-Carboxylic Acids for the Manufacturing of Solid Oral Forms with Copovidone and Ibuprofen by Selective Laser Sintering.

In selective laser sintering (SLS), the heating temperature is a critical parameter for printability but can also be deleterious for the stability of active ingredients. This work aims to explore the plasticizing effect of di-carboxylic acids on reducing the optimal heating temperature (OHT) of polymer powder during SLS. First, mixtures of copovidone and di-carboxylic acids (succinic, fumaric, maleic, malic and tartaric acids) as well as formulations with two forms of ibuprofen (acid and sodium salt) were prepared to sinter solid oral forms (SOFs), and their respective OHT was determined. Plasticization was further studied by differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR). Following this, the printed SOFs were characterized (solid state, weight, hardness, disintegration time, drug content and release). It was found that all acids (except tartaric acid) reduced the OHT, with succinic acid being the most efficient. In the case of ibuprofen, only the acid form demonstrated a plasticizing effect. DSC and FTIR corroborated these observations showing a decrease in the glass transition temperature and the presence of interactions, respectively. Furthermore, the properties of the sintered SOFs were not affected by plasticization and the API was not degraded in all formulations. In conclusion, this study is a proof-of-concept that processability in SLS can improve with the use of di-carboxylic acids.

Comparison of the Surface Properties of Hydrothermally Synthesised Fe3O4@C Nanocomposites at Variable Reaction Times.

The influence of variable reaction time (tr) on surface/textural properties (surface area, total pore volume, and pore diameter) of carbon-encapsulated magnetite (Fe3O4@C) nanocomposites fabricated by a hydrothermal process at 190 °C for 3, 4, and 5 h was studied. The properties were calculated using the Brunauer-Emmett-Teller (BET) isotherms data. The nanocomposites were characterised using Fourier transform infrared spectroscopy, X-ray diffraction analysis, thermogravimetry, and scanning and transmission electron microscopies. Analysis of variance shows tr has the largest effect on pore volume (F value = 1117.6, p value < 0.0001), followed by the surface area (F value = 54.8, p value < 0.0001) and pore diameter (F value = 10.4, p value < 0.001) with R2-adjusted values of 99.5%, 88.5% and 63.1%, respectively. Tukey and Fisher tests confirmed tr rise to have caused increased variations in mean particle sizes (11-91 nm), crystallite sizes (5-21 nm), pore diameters (9-16 nm), pore volume (0.017-0.089 cm3 g-1) and surface area (7.6-22.4 m2 g-1) of the nanocomposites with individual and simultaneous confidence limits of 97.9 and 84.4 (p-adj < 0.05). The nanocomposites' retained Fe-O vibrations at octahedral (436 cm-1) and tetrahedral (570 cm-1) cubic ferrite sites, modest thermal stability (37-60 % weight loss), and large volume-specific surface area with potential for catalytic application in advanced oxidation processes.

Glutathione-mediated formation of disulfide bonds modulates the properties of myofibrillar protein gels at different temperatures.

The present study illustrated modulation of protein aggregation by affecting disulfide/sulfhydryl exchange reactions by adding different concentrations of free thiol represented by reduced-glutathione (GSH) for modulating myofibrillar protein (MP) gel properties at 75 °C or 95 °C. Gel strength and rheological results showed the effects of GSH were dependent on the concentrations (5, 10, 20, 40, and 80 g/kg) and heating temperatures. SEM results showed that the addition of GSH improved the gel microstructure at 95 °C. AFM and DLS results indicated that protein aggregation was also inhibited. At 75 °C, the addition of GSH influenced both MP aggregation and gel properties. Low concentrations (5, 10 g/kg) of GSH promoted aggregation, whereas high concentrations (20, 40, and 80 g/kg) of GSH inhibited this. By analyzing the protein structure and cross-linking pattern changes of MP and MP/GSH composites, a pathway involving GSH influencing MP gel properties was determined.

Heating temperature dependence of molecular characteristics and biological response for biomass pyrolysis volatile-derived water-dissolved organic matter.

The utilization of biomass pyrolysis volatile-derived water-dissolved organic matter (WOM, often called wood vinegar) determines sustainable recycling of biomass. Further, pyrolysis temperature significantly controls the cracking of biomass components, resulting in various molecular compositions and biological responses of WOM. Although it has been widely used in the agriculture, the relationship between molecular compositions and biological responses affected by heating temperature is still unclear. Here, it was observed that the WOM concentration increased with increasing temperatures and the pyrolysis of 1 g biomass can generate ~ WOM with 36.24 mg C. Moreover, with increasing pyrolysis temperatures, the generated WOM consisted of more phenols but fewer alcohols, furans, acids, and ketones, and demonstrated characteristics of higher aromaticity and lower m/z molecular weight. Due to the enhanced polarity, high temperatures promoted the solubility of WOM. Germination tests show that low pyrolysis temperatures-derived WOM (< 400 °C) with large-molecular-weight and low oxygen-containing (low O/Cwa) promoted plant growth, while high temperatures-derived WOM (> 400 °C) with small-molecular-weight and high oxygen-containing (high O/Cwa) inhibited growth. These results suggest that WOM can be separately collected at different pyrolysis temperatures to achieve sustainable recycling of pyrolysis volatile.

Evaluation of pasting and gelling properties of commercial flours under high heating temperatures using Rapid Visco Analyzer 4800.

In this study, pasting and gelling behaviors of flours were investigated at heating temperatures of 95-140 °C. Overall, both peak and breakdown viscosities of the flours were positively correlated with starch contents (p < 0.01) but inversely correlated with protein (p < 0.01) and fiber contents (p < 0.05) at 95-140 °C. When the heating temperature increased, pasting temperatures and peak viscosities of most waxy and normal flours largely remained the same, but their holding strengths and final viscosities gradually decreased. However, pulse and high-amylose maize flours required a holding temperature above 95 °C to achieve the highest peak and final viscosities. Normal maize and pulse flours formed hard gels after cooking at 120 °C, and high-amylose maize flour developed the firmest gel after cooking at 140 °C. Chemical compositions, particle sizes, and thermal properties of the studied flours influenced their pasting and gelling properties to certain levels under the different heating temperatures.

Optimization Study on Specific Loss Power in Superparamagnetic Hyperthermia with Magnetite Nanoparticles for High Efficiency in Alternative Cancer Therapy.

The cancer therapy with the lowest possible toxicity is today an issue that raises major difficulties in treating malignant tumors because chemo- and radiotherapy currently used in this field have a high degree of toxicity and in many cases are ineffective. Therefore, alternative solutions are rapidly being sought in cancer therapy, in order to increase efficacy and a reduce or even eliminate toxicity to the body. One of the alternative methods that researchers believe may be the method of the future in cancer therapy is superparamagnetic hyperthermia (SPMHT), because it can be effective in completely destroying tumors while maintaining low toxicity or even without toxicity on the healthy tissues. Superparamagnetic hyperthermia uses the natural thermal effect in the destruction of cancer cells, obtained as a result of the phenomenon of superparamagnetic relaxation of the magnetic nanoparticles (SPMNPs) introduced into the tumor; SPMNPs can heat the cancer cells to 42-43 °C under the action of an external alternating magnetic field with frequency in the range of hundreds of kHz. However, the effectiveness of this alternative method depends very much on finding the optimal conditions in which this method must be applied during the treatment of cancer. In addition to the type of magnetic nanoparticles and the biocompatibility with the biological tissue or nanoparticles biofunctionalization that must be appropriate for the intended purpose a key parameter is the size of the nanoparticles. Also, establishing the appropriate parameters for the external alternating magnetic field (AMF), respectively the amplitude and frequency of the magnetic field are very important in the efficiency and effectiveness of the magnetic hyperthermia method. This paper presents a 3D computational study on specific loss power (Ps) and heating temperature (ΔT) which allows establishing the optimal conditions that lead to efficient heating of Fe3O4 nanoparticles, which were found to be the most suitable for use in superparamagnetic hyperthermia (SPMHT), as a non-invasive and alternative technique to chemo- and radiotherapy. The size (diameter) of the nanoparticles (D), the amplitude of the magnetic field (H) and the frequency (f) of AMF were established in order to obtain maximum efficiency in SPMHT and rapid heating of magnetic nanoparticles at the required temperature of 42-43 °C for irreversible destruction of tumors, without affecting healthy tissues. Also, an analysis on the amplitude of the AMF is presented, and how its amplitude influences the power loss and, implicitly, the heating temperature, observables necessary in SPMHT for the efficient destruction of tumor cells. Following our 3D study, we found for Fe3O4 nanoparticles the optimal diameter of ~16 nm, the optimal range for the amplitude of the magnetic field of 10-25 kA/m and the optimal frequency within the biologically permissible limit in the range of 200-500 kHz. Under the optimal conditions determined for the nanoparticle diameter of 16.3 nm, the magnetic field of 15 kA/m and the frequency of 334 kHz, the magnetite nanoparticles can be quickly heated to obtain the maximum hyperthermic effect on the tumor cells: in only 4.1-4.3 s the temperature reaches 42-43 °C, required in magnetic hyperthermia, with major benefits in practical application in vitro and in vivo, and later in clinical trials.

Variations in Ginsenosides of Raw Ginseng According to Heating Temperature and Time.

OBJECTIVES: Ginsenosides found in ginseng, and the hydrolysates derived from their conversion, exhibit diverse pharmacological characteristics [1]. These have been shown to include anti-cancer, anti-angiogenic, and anti-metastatic effects, as well as being able to provide hepatic and neuroprotective effects, immunomodulation, vasodilation, promotion of insulin secretion, and antioxidant activity. Therefore, the purpose of this study was to examine how quickly the ginsenosides decompose and what kinds of degradation products are created under physicochemical processing conditions that don't involve toxic chemicals or other treatments that may be harmful. METHODS: The formation of ginsenoside-Rg2 and ginsenoside-Rg3 was examined. These demonstrated diverse pharmacological effects. RESULTS: We also investigated physicochemical factors affecting their conversion. The heating temperatures and times yielding the highest concentration of ginsenosides (-Rb1, -Rb2, -Rc, -Rd, -Rf, -Rg1, and -Re) were examined. Additionally, the heating temperatures and rates of conversion of these ginsenosides into new 'ginseng saponins', were examined. CONCLUSION: In conclusion, obtained provide us with effective technology to control the concentration of both ginsenosides and the downstream converted saponins (ginsenoside-Rg2, Rg3, Rg5, and Rk1 etc.), as well as identifying the processing conditions which enable an enrichment in concentration of these compounds.

Organic fragments newly released from heat-treated peat soils create synergies with dissolved organic carbon to enhance Cr(VI) removal.

Surface fires occur naturally or anthropogenically and can raise the temperature at the soil surface up to 600 °C. The heat derived from the surface fire can be subsequently transferred into CO2-enriched subsoils. As a result, the chemical compositions of soil organic matter (SOM) may be altered in fire-impacted anaerobic environments, indirectly influencing the redox transformations of pollutants, such as Cr(VI). In this study, a peat soil was heated up to 600 °C with limited air flow to simulate the effects of heat on the SOM during surface fire events. Then, Cr(VI) removal, including reduction and sorption, by the heat-treated peat soils was determined in relation to changes in the soil organic components. The results showed that the amount of O-containing functional groups, -CH2/-CH3 units of aliphatic groups, and dissolved organic carbon (DOC) in the SOM gradually decreased with an increase in the heating temperature. The removal of 0.1932 mM Cr(VI) did not exhibit a consistent decline along with the changes in these soil components. The heating temperatures of 200 and 250 °C were the thresholds that led to the decomposition of temperature-sensitive soil organic components such as lignin and other labile SOM. Such newly released organic fragments synergized lignin-like substances and carboxyl groups, resulting in up to 99% removal of the initially added Cr(VI). As the heating temperatures were increased from 300 to 600 °C, Cr(VI) reduction decreased from 66% to 20%. The black carbon-like materials and/or aromatic-containing moieties were the major components responsible for Cr(VI) reduction in 600°C-treated peat soils.

Finite Element Analysis of Extrusion Process for Magnesium Alloy Internal Threads with Electromagnetic Induction-Assisted Heating and Thread Performance Research.

The casting magnesium alloy AZ91D cannot be extruded at room temperature. This paper presents a process for extruding internal threads using AZ91D heated by electromagnetic induction. The feasibility of the process is verified by finite element simulation and experiments. Using DEFORM-3D to simulate the process of extruding a M12 × 1.25 mm threaded hole by electromagnetic induction-assisted heating, the equivalent stress-strain and material flow law in the process of thread deformation was analyzed and verified by experiments. Three parameters-hole diameter, machine speed and heating temperature-were considered to study the influence of different process conditions on the forming torque. The results show that a heating temperature above 523 K can improve the plasticity of AZ91D. The hole diameter has an important influence on the forming torque. The forming process is not suitable for high-speed machining. The surface metal of the thread formed by this process has a strong deformation layer, which can improve the strength and hardness of the thread.