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•A method of removing microplastics by magnetic carbon nanotubes was proposed.•Excellent performance of 100% removal was achieved for microplastics.•The mechanism of magnetic carbon ...nanotubes adsorption had been deeply discussed.•The recovering of magnetic carbon nanotubes and reusability were also investigated.
Microplastics (MPs), as reservoirs of cocktail of contaminants, impose severe impacts on human and ambient water environment. Therefore, efficient and eco-friendly MPs removal techniques are urgently needed. In this study, for the first time, magnetic carbon nanotubes (M−CNTs) have been synthesized as adsorbates to remove MPs. M−CNTs were effectively adsorbed on polyethylene (PE), polyethylene terephthalate (PET), and polyamide (PA) and all the MPs/M−CNTs composites were readily separated from aqueous solutions by magnetic force. When the 5 g⋅L−1 of M−CNTs was added, target MPs (5 g⋅L−1) were completely removed within 300 min. The maximum adsorption capacities of PE, PET and PA were 1650, 1400 and 1100 mg-M−CNTs⋅g−1, respectively. This process was hardly affected by the COD, NH3-N, and PO43− substance and all MPs were completely removed from the wastewater discharged from a kitchen waste treatment plant. Furthermore, the adsorbed M−CNTs can be recycled via thermal treatment (600 °C) and these M−CNTs were featured with the same magnetic properties and comparable MPs removal capacity to the original ones. After being used for four times, M−CNTs were still able to remove ~80% of total MPs in the testing solution. The observed effectual removal of MPs from prepared solutions and wastewater highlights M−CNTs as promising techniques for the control of MPs pollution.
The microstructure evolution of the γ′ precipitates in GH4720Li superalloy during the heat treatment processes of water quenching and subsequent aging at temperatures of 760 °C, 800 °C, and 850 °C ...was investigated with particular emphasis on the variation in the morphology, size, and size distribution of the precipitates and related mechanisms. Influence of aging temperature and time on the nucleation, growth, and coarsening behavior of the bimodal dispersion of secondary and tertiary γ′ precipitates were discussed. Results showed that only spherical-shaped secondary γ′ precipitates with sizes ranging from 10 to 50 nm formed during the cooling process of quenching. During aging, the nucleation of tertiary γ′ precipitate, growth of both secondary and tertiary γ′ precipitates follow the typical solid-diffusion-assisted precipitation mechanism, while the abnormal coarsening of the secondary precipitates occurs through coalescing adjacent particles. Aging temperature has a less effect on the precipitation of the tertiary γ′ precipitate but substantially influences the coarsening of the secondary γ′ precipitates. At higher aging temperatures such as 850 °C, the abnormal coarsening of the secondary γ′ precipitates, which always takes place at 760 °C and 800 °C, are significantly suppressed. The aging time mainly influences the growth rate of the secondary γ′ but shows little effect on the evolution of the tertiary γ′ phase. Precipitates strengthen the alloy through strong coupling interaction mechanism. An optimal aging strategy heating at 850 °C for 8 h is proposed for the GH4720Li superalloy, yielding the best uniform dispersion of the precipitates, maximum hardness of the sample, and being considered time and energy-saving.
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•The bio-model of microstructure evolution of the γ′ precipitates in GH4720Li superalloy during the heat treatment processes was investigated.•The nucleation, growth, and coarsening behavior of the bimodal dispersion of secondary and tertiary γ′ precipitates were discussed.•Aging temperature has a lesser effect on the precipitation of the tertiary γ′ precipitate but substantially influences the coarsening of the secondary γ′ precipitates.•The aging time mainly influences the growth rate of the secondary γ′ but shows little effect on the evolution of the tertiary γ′ phase.
Owing to the postharvest mass loss in most tropical and subtropical fruits and vegetables caused by chilling injury (CI), it is necessary to look for effective technologies to alleviate this issue. ...Studies thus far have found that some postharvest technologies could effectively alleviate CI in post-harvest fruits and vegetables.
This review summarizes the temperature and symptoms of CI in common postharvest fruits and vegetables. The postharvest technologies to control CI, which comprised physical (low-temperature conditioning, heat treatment, near-freezing temperature, controlled atmosphere, edible coating and ultraviolet irradiation) and chemical (ethylene and 1-methylcyclopropene, oxalic acid, calcium ions, nitric oxide, melatonin, salicylates and jasmonates, polyamines, and some other chemical substances) treatments, are also detailed. The potential biochemical mechanisms of different postharvest technologies are also proposed and attributed to the following strategies: maintaining membrane structure and sufficient energy supply, enhancing the antioxidant system, promoting the arginine pathway, regulating sugar metabolism, and activating the C-repeat/dehydration response element binding factor (CBF) genes.
This review found that a variety of postharvest treatments have been developed to control CI in postharvest fruits and vegetables. The key findings were that the effects of some postharvest treatments—such as ethylene and 1-methylcyclopropene—on fruit and vegetable CI are contradictory. Some key factors, such as the time and temperature of heat treatment and the dose of ultraviolet radiation, need to be regarded when applying postharvest technologies. Some small-molecule signal substances that from natural plant and the combination of different treatments are potential future research directions for controlling CI in postharvest fruits and vegetables.
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•The temperature and symptom of chilling injury (CI) of common product are summarized.•The technologies and biochemical mechanism to control the CI are summarized.•The effect of some technologies on CI of fruits and vegetables are contradictory.•There are some key factors when some technologies applied for alleviating CI.
One great challenge for perovskite solar cells (PSCs) lies in their poor operational stability under harsh stimuli by humidity, heat, light, etc. Herein, a thermal‐triggered self‐healing polyurethane ...(PU) is tailored to simultaneously improve the efficiency and stability of inorganic CsPbIBr2 PSCs. The dynamic covalent disulfide bonds between adjacent molecule chains in PU at high temperatures self‐heal the in‐service formed defects within the CsPbIBr2 perovskite film. Finally, the best device free of encapsulation achieves a champion efficiency up to 10.61 % and an excellent long‐term stability in an air atmosphere over 80 days and persistent heat attack (85 °C) over 35 days. Moreover, the photovoltaic performances are recovered by a simple heat treatment.
A functionalized polyurethane is used as an additive to self‐heal a CsPbIBr2 film by a disulfide‐exchange reaction upon heat treatment. The inorganic CsPbIBr2 perovskite solar cell achieves a champion efficiency of 10.61 % with efficiency recovery after heat treatment.
This book describes the basic principles of heat-treating technology in clear, concise, and practical terms for students, emerging professionals, production personnel, and manufacturing or design ...engineers.
Fe2O3‐coated FeSiCr(FeSiCr@Fe2O3) nanoparticles were prepared by plasma arc discharge method and oxidation heat treatment process, and the crystallinity of Fe2O3 was improved by vacuum heat ...treatment. By adjusting the oxidation temperature, Fe2O3 shell layer is formed on the surface of FeSiCr nanoparticles. The thickness of the Fe2O3 shell layer increases with the increase of oxidation temperature. The complex permittivity (εr${\varepsilon _r}$) and complex permeability (μr${\mu _r}$) show a trend of first increasing and then decreasing. When the oxidation temperature is 125°C, the minimum reflection loss (RLmin) of FeSiCr@Fe2O3 nanoparticles is calculated to be −23.7 dB at 11.2 Ghz (d = 2.2 mm). With the increase of the temperature of vacuum heat treatment, the crystallinity of Fe2O3 shell keeps increasing. The real and imaginary values (ε′$\varepsilon ^{\prime}$ and ε′′$\varepsilon ^{\prime\prime}$) of the complex permittivity of FeSiCr@Fe2O3 nanoparticle increase with the increase of the crystallinity of Fe2O3 shell, and the μr${\mu _r}$ basically remains unchanged. When the vacuum heat treatment temperature is 150°C, the FeSiCr@Fe2O3 nanoparticle obtains RLmin of −49.9 dB at 15.9 Ghz (d = 1.7 mm). And the corresponding effective absorption bandwidth within 1‐18 GHz (RL ≤ −10 dB) is 5.9 GHz. The improved microwave performance is due to the interface polarization of the core‐shell structure, and the synergistic effect between FeSiCr and Fe2O3 also helps to balance the electromagnetic parameters.
The graphical describes the experimental process, the micro morphology and microwave absorption mechanism of samples.
•We examine stress–strain behavior for 17–4 PH processed by selective laser melting.•We measure evolution of volumetric fractions for phases with heat treatment.•Peak age treatment strengthens while ...maintaining high austenite volumetric fraction.•As-fabricated and peak age treatments demonstrate significant work hardening.•Retained austenite transforms to martensite following overaged treatments.
Thermal processing and mechanical characterization of tensile specimens fabricated from bulk 17–4 PH material produced by selective laser melting (SLM) is presented. Prior to specimen evaluation, various industry standard and non-standard heat treatments were performed. The focus of this thermal processing was to evaluate the effect of aging on mechanical performance with or without a prior solution heat treatment. Volumetric fraction of metastable austenite was measured to vary with heat treatments performed and the initial conditions from which aging was initiated. Material aged following a solution heat treatment was found to have an austenite reversion from a fully martensitic structure to volumetric fractions as high as 20.4%. Whereas, initial concentrations of retained austenite in SLM as-fabricated material increased following a peak-age heat treatment, but decreased with higher temperature, overaged heat treatments. Specimens with large amounts of austenite demonstrated stress-induced transformation to martensite during tensile testing. This behavior was reflected in substantially reduced yield strengths, increased work hardening rates across greater ranges of strain, and delayed onset of localized plastic deformation. Ultimate tensile strengths for varieties of specimens aged to the peak-aged condition were similar, but differed greatly at strain levels where this strength was achieved.
The objective of this study was to determine the effect of the heat treatment (HT, 60°C for 60 min) on the concentration of bovine colostrum oligosaccharides (bCO) in pooled bovine colostrum and the ...intestine of neonatal male Holstein calves after feeding. First-milking colostrum was pooled from both primiparous and multiparous cows, and half of the pooled colostrum was heat-treated at 60°C for 60 min (HC), whereas the other half was not heat-treated and remained fresh (FC). At birth, 32 male Holstein calves were randomly assigned to 1 of 3 treatment groups: (1) control calves that did not receive colostrum for the duration of the experiment and were euthanized at 6 h (NC, n = 4) or 12 h (NC, n = 4), (2) calves fed fresh colostrum (FC) and were euthanized at 6 h (FC, n = 6) or 12 h (FC, n = 6), or (3) calves fed heat-treated colostrum (HC) and euthanized at 6 h (HC, n = 6) or 12 h (HC, n = 6). All calves were fed 2 L of colostrum within 1 h after birth. At dissection, digesta of the distal jejunum, ileum, and colon was collected and analyzed by liquid chromatography-mass spectrometry to determine the concentration of bCO within each intestinal region. The heat-treated colostrum displayed numerically higher concentrations of total bCO (3,511.6 μg/g) when compared with fresh colostrum (1,329.9 μg/g), with 3′-sialyllactose being the most abundant bCO in both fresh and HT colostrum. In contrast, calves fed HT colostrum displayed a lower amount of total bCO in the distal jejunum (221.91 ± 105.3 vs. 611.26 ± 265.1 μg/g), ileum (64.97 ± 48.39 vs. 344.04 ± 216.87 μg/g), and colon (25.60 ± 13.1 vs. 267.04 ± 125.81 μg/g) at 6 h of life when compared with calves fed fresh colostrum. No differences were observed in regard to the concentrations of total bCO in the intestine of FC and HC calves at 12 h of life. It is speculated that lower concentrations of bCO in the gastrointestinal tract of HC calves at 6 h of life could be due to the early establishment of beneficial bacteria, such as Bifidobacterium, in HC calves and their subsequent metabolism of bCO as a carbon source. These findings suggest that the heat treatment of colostrum increases the amount of free bCO, which may serve as prebiotics available to microbiota within the intestine of the neonatal calf.
Due to easy re-stacking, low yield of few-layered MXenes (f-MXenes), the applications of MXenes are mainly restricted in multi-layered MXenes (m-MXenes) state. Although f-MXenes can be prepared from ...m-MXenes, after exfoliation process, a mass of sediments which are still essentially compact MXenes are usually directly discarded, leading to low utilization of raw m-MXenes. Herein, a classified preparation strategy is adopted to exploit the raw m-MXenes and traditional MXenes sediments, taking multi-layered Ti
3
C
2
T
x
MXene as an example. Via rational delamination and subsequent treatment to Ti
3
C
2
T
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sediments, we succeed in achieving classified and large-scale preparation of various Ti
3
C
2
T
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MXene derivatives, including few-layered Ti
3
C
2
T
x
(f-Ti
3
C
2
T
x
) powders, f-Ti
3
C
2
T
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films, and Ti
3
C
2
T
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MXene-derived nanowires with heterostructure of potassium titanate and Ti
3
C
2
T
x
. We demonstrate the necessity of “step-by-step delamination” towards traditional Ti
3
C
2
T
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sediments to improve the yield of f-Ti
3
C
2
T
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from 15% to 72%; the feasibility of “solution-phase flocculation (SPF)” to fundamentally solve the re-stacking phenomenon, and oxidation degradation issues of f-Ti
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C
2
T
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during storage; as well as the convenience of SPF to deal with time-consuming issues of fabricating Ti
3
C
2
T
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films. What’s more, alkali-heat treatment of final Ti
3
C
2
T
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sediments turns waste into treasure of Ti
3
C
2
T
x
-derived nanowires, leading to 100% utilization of raw Ti
3
C
2
T
x
. The content of one-dimensional (1D) nanowires in the hybrids can be adjusted by controlling alkalization time. The 3D architecture heterostructure composed of 1D nanowires and 2D nanosheets exhibits gorgeous application potential. This work can expand preparation and application of various MXenes derivatives, promoting process of various MXenes.
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