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1.
Molecules ; 29(17)2024 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-39274999

RESUMO

Multifunctional thermal regulation materials with good thermal properties, efficient magnetic performance, and satisfactory interface bonding on fabrics are highly desirable for protective fabrics, building winter protection materials, medical thermal regulation materials, and special-environment work clothing. Herein, a new class of magnetic phase-change PW@CaCO3@Fe3O4 microcapsules was successfully produced by controlling the content of magnetic Fe3O4 through a self-assembly method. The microstructure, chemical composition, phase-change behavior, and magnetic properties of the products were sequentially characterized and analyzed. The findings revealed that the obtained microcapsules possessed regular spherical structure with uniform size and excellent thermal properties. Furthermore, PW@CaCO3 with Fe3O4 (i.e., 8% mass fraction) showed the highest thermal regulation and magnetic properties and reached an enthalpy value of 94.25 J·g-1, which is clearly superior to the value of 77.51 J·g-1 for PW@CaCO3 microcapsules. At the same time, the encapsulation efficiency of 38.7% and saturation magnetization of 2.50 emu·g-1 were the best among the four given samples. Therefore, the good paramagnetic feature had a significant synergistic effect on the thermal properties of the PW@CaCO3 microcapsules under study. More importantly, multifunctional fabrics loaded with PW@CaCO3@Fe3O4 microcapsules still showed an enthalpy value of 25.81 J·g-1 after several washes and have the potential to be used widely in the field of temperature control. The thermal regulation fabrics in this study exhibited excellent thermal properties and fastness, which contribute to their practical applications in advancing multifunctional textiles and high-technology modern fabrics.

2.
Macromol Rapid Commun ; 44(10): e2200910, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37017474

RESUMO

This work synthesizes a new bifunctional furan derivative (PDMS-FBZ) through a sequence of hydrosilylation of nadic anhydride (ND) with polydimethylsiloxane (PDMS), reaction of the product with p-aminophenol to form PDMS-ND-OH, and its subsequent Mannich reaction with furfurylamine and CH2 O. Then, the main chain-type copolymer PDMS-DABZ-DDSQ is prepared through a Diels-Alder (DA) cycloaddition of PDMS-FBZ with the bismaleimide-functionalized double-decker silsesquioxane derivative DDSQ-BMI. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy confirm the structure of this PDMS-DABZ-DDSQ copolymer; differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA) reveal it to have high flexibility and high thermal stability (Tg = 177 °C; Td10 = 441 °C; char yield = 60.1 wt%); contact angle measurements reveal a low surface free energy (18.18 mJ m-2 ) after thermal ring-opening polymerization, because the inorganic PDMS and DDSQ units are dispersed well, as revealed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). This PDMS-DABZ-DDSQ copolymer possesses reversible properties arising from the DA and retro-DA reactions, suggesting its possible application as a functional high-performance material.


Assuntos
Benzoxazinas , Polímeros , Reação de Cicloadição , Benzoxazinas/química , Polímeros/química , Microscopia Eletrônica de Varredura , Dimetilpolisiloxanos
3.
Molecules ; 28(10)2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-37241832

RESUMO

Crystalline/crystalline blends of polymer have shown advantages in the preparation of new polymeric materials. However, the regulation of co-crystallization in a blend is still full of challenges due to the preferential self-crystallization driven by thermodynamics. Here, an inclusion complex approach is proposed to facilitate the co-crystallization between crystalline polymers, because the crystallization process displays a prominent kinetics advantage when polymer chains are released from the inclusion complex. Poly(butylene succinate) (PBS), poly(butylene adipate) (PBA) and urea are chosen to form co-inclusion complexes, where PBS and PBA chains play as isolated guest molecules and urea molecules construct the host channel framework. The coalesced PBS/PBA blends are obtained by fast removing the urea framework and systematically investigated by differential scanning calorimetry, X-ray diffraction, proton nuclear magnetic resonance and Fourier transformation infrared spectrometry. It is demonstrated that PBA chains are co-crystallized into PBS extended-chain crystals in the coalesced blends, while such a phenomenon has not been detected in simply co-solution-blended samples. Though PBA chains could not be totally accommodated in the PBS extended-chain crystals, their co-crystallized content increases with the initial feeding ratio of PBA. Consequently, the melting point of the PBS extended-chain crystal gradually declines from 134.3 °C to 124.2 °C with an increasing PBA content. The PBA chains playing as defects mainly induce lattice expansion along the a-axis. In addition, when the co-crystals are soaked in tetrahydrofuran, some of the PBA chains are extracted out, leading to damage to the correlative PBS extended-chain crystals. This study shows that co-inclusion complexation with small molecules could be an effective way to promote co-crystallization behavior in polymer blends.

4.
Molecules ; 28(6)2023 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-36985509

RESUMO

As a common two-dimensional carbon material, graphene has been widely doped into polymers to prepare high-performance dielectric materials. However, the shortcomings of graphene, such as large specific surface area and poor dispersion, limit its further application. Therefore, in this work, to solve the problem regarding the uniform dispersion of graphene in the matrix, in situ polymerization was used to prepare graphene/polyimide films, in which 1,4-diiodobutane was used as a reduction agent to prevent the aggregation of graphene oxide (GO) during imidization. High dielectric constant composite films were obtained by adjusting the ratio of 1,4-diiodobutane in GO. The results show that the resulting graphene/polyimide composite film possessed a dielectric constant of up to 197.5, which was more than 58 times higher than that of the polyimide (PI) film. Furthermore, compared to the pure PI film, the composite films showed better thermal stability and mechanical properties. Thermal performance tests showed that the 1,4-diiodobutane added during the preparation of the composite film was thermally decomposed, and there was no residue. We believe our preparation method can be extended to other high dielectric composite films, which will facilitate their further development and application in high power density energy storage materials.

5.
J Sci Food Agric ; 103(14): 7302-7313, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37499162

RESUMO

BACKGROUND: Chalkiness in rice reduces its market value and affects consumer acceptance. Research on the mechanism of chalkiness formation has focused primarily on the activity of key enzymes of carbon metabolism and starch accumulation. The relationship between the formation of chalkiness induced by N fertilizer and rice starch's multi-level structure and thermal properties still needs to be fully elucidated. RESULTS: In this study, the rates of chalky grains and degree of chalkiness decreased with the increase in N fertilizer dosage. This was attributed to an increased proportion of short chains, ordered structure carbon chains, small starch granules, and branched starches, and a higher degree of crystallinity and ΔHg in protein, and a decreased proportion of amylose, large starch granules, and weighted average diameter of starch granule surface area and volume. Application of N fertilizer promoted an increased proportion of short-branched chain amylopectin to develop a more ordered carbohydrate structure and crystalline lamella. These effects enhanced the normal development and compactness of starch granules in grains, and improved their arrangement morphology, thereby reducing the chalkiness in rice. CONCLUSION: These changes in starch multi-level structure and protein improve the physicochemical characteristics of starch and enhance the fullness, crystallinity and compactness of starch granules, while synergistically increasing the regularity and homogeneity of starch granules and thus optimizing the stacking pattern of starch granules, leading to a reduction in rice chalkiness under nitrogen fertilization and thus improving the appearance of rice. © 2023 Society of Chemical Industry.

6.
Sensors (Basel) ; 22(2)2022 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-35062389

RESUMO

This paper provides a comprehensive review on the use of infrared thermography to detect delamination on infrastructures and buildings. Approximately 200 pieces of relevant literature were evaluated, and their findings were summarized. The factors affecting the accuracy and detectability of infrared thermography were consolidated and discussed. Necessary measures to effectively capture latent defects at the early stage of delamination before crack formation were investigated. The results of this study could be used as the benchmarks for setting standardized testing criteria as well as for comparison of results for future works on the use of infrared thermography for detection of delamination on infrastructures and buildings.


Assuntos
Raios Infravermelhos , Termografia
7.
Int J Mol Sci ; 24(1)2022 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-36613777

RESUMO

Exopolysaccharides produced by edible microorganisms exhibit excellent constructive physicochemical and significant biological activity, which provide advantages for the food or pharmaceutical industries. Two novel exopolysaccharides produced by Debaryomyces hansenii DH-1 were characterized, named S1 and S2, respectively. S1, with a molecular weight of 34.594 kDa, primarily consisted of mannose and glucose in a molar ratio of 12.19:1.00, which contained a backbone fragment of α-D-Manp-(1→4)-α-D-Manp-(1→2)-α-D-Glcp-(1→3)-α-D-Manp-(1→3)-ß-D-Glcp-(1→4)-ß-D-Manp-(1→. S2, with a molecular weight of 24.657 kDa, was mainly composed of mannose and galactose in a molar ratio of 4.00:1.00, which had a backbone fragment of α-D-Manp-(1→6)-ß-D-Manp-(1→2)-α-D-Manp-(1→4)-α-D-Galp-(1→3)-ß-D-Manp-(1→6)-α-D-Manp-(1→. Both S1 and S2 exhibited good thermal stability and potent hydroxyl radical scavenging activity, with ~98%. Moreover, S1 possessed an additional strong iron-reducing capacity. In vitro antitumor assays showed that S1 and S2 significantly inhibited the proliferation of Hela, HepG2, and PC-9 cancer cells. Moreover, PC-9 was more sensitive to S1 compared with S2. The above results indicate that S1 and S2 have great potential to be utilized as natural antioxidants and candidates for cancer treatment in the food and pharmaceutical industries.


Assuntos
Antioxidantes , Debaryomyces , Antioxidantes/farmacologia , Antioxidantes/química , Manose , Peso Molecular , Galactose , Polissacarídeos/química
8.
J Sci Food Agric ; 102(7): 2813-2825, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-34738641

RESUMO

BACKGROUND: The major by-products of mango processing are the seeds, which represent approximately 15-20% of the fruit. The process protocol for isolation of starch from mango kernel was standardized based on starch yield, starch purity and colour values using centrifugation and chemical method. Optimized starches obtained from both methods were further investigated for estimation of functional properties and were characterized through Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry and pasting properties analysis. RESULTS: The slurry making of mango kernels with a solid-to-water ratio of 1:3 at a centrifugation frequency of 3 times was found to be the best among all the experimental combinations (solid-to-water proportion (1:2, 1:3 and 1:4, w/v) and centrifugation frequency (2, 3 and 4 times)) with a starch yield of 48.43 ± 1.08% and purity of 76.46 ± 0.83%. In the chemical method of starch isolation (washing was done with 0.1 mol L-1 NaOH and 0.1 mol L-1 HCl at three levels each), the sample treated with 60% (w/v) 0.1 mol L-1 NaOH and 10% (w/v) 0.1 mol L-1 HCl resulted in 36.50 ± 0.58% starch yield with a purity of 92.03 ± 0.87%. Among the functional properties, the chemically isolated starch showed significantly higher paste clarity (45.79 ± 2.36%) than starch obtained using the centrifugation process (12.50 ± 1.57%). The chemically isolated starch also exhibited better colour attributes, which were very close to those of laboratory-grade starch. CONCLUSION: Detailed characterization studies inferred that both the starches possessed good functional, structural and thermal properties, indicating suitability for food and non-food applications. © 2021 Society of Chemical Industry.


Assuntos
Mangifera , Amido , Amilose/química , Mangifera/química , Padrões de Referência , Hidróxido de Sódio , Amido/química , Água , Difração de Raios X
9.
J Biomech Eng ; 142(12)2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-32391553

RESUMO

Treatment of atrial fibrillation by cryoablation of the pulmonary vein (PV) suffers from an inability to assess probe contact, tissue thickness, and freeze completion through the wall. Unfortunately, clinical imaging cannot be used for this purpose as these techniques have resolutions similar in scale (∼1 to 2 mm) to PV thickness and therefore are unable to resolve changes within the PV during treatment. Here, a microthermal sensor based on the "3ω" technique which has been used for thin biological systems is proposed as a potential solution and tested for a cryoablation scenario. First, the sensor was modified from a linear format to a serpentine format for integration onto a flexible balloon. Next, using numerical analyses, the ability of the modified sensor on a flat substrate was studied to differentiate measurements in limiting cases of ice, water, and fat. These numerical results were then complemented by experimentation by micropatterning the serpentine sensor onto a flat substrate and onto a flexible balloon. In both formats (flat and balloon), the serpentine sensor was experimentally shown to: (1) identify tissue contact versus fluid, (2) distinguish tissue thickness in the 0.5 to 2 mm range, and (3) measure the initiation and completion of freezing as previously reported for a linear sensor. This study demonstrates proof of principle that a serpentine 3ω sensor on a balloon can monitor tissue contact, thickness, and phase change which is relevant to cryo and other focal thermal treatments of PV to treat atrial fibrillation.


Assuntos
Criocirurgia , Veias Pulmonares , Fibrilação Atrial , Ablação por Cateter , Humanos , Pessoa de Meia-Idade
10.
Molecules ; 25(14)2020 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-32708238

RESUMO

Polylactic acid (PLA) is one of the most promising biodegradable and recyclable thermoplastic biopolymer derived from renewable feedstock. Nanocellulose reinforced PLA biocomposites have received increasing attention in academic and industrial communities. In the present study, cellulose nanofibrils (CNFs) was liberated by combined enzymatic pretreatment and high-pressure homogenization, and then subsequently incorporated into the PLA matrix to synthesize PLA/CNF biocomposite films via solution casting and melt compression. The prepared PLA/CNF biocomposite films were characterized in terms of transparency (UV-Vis spectroscopy), chemical structure (attenuated total reflectance-Fourier transform infrared, ATR-FTIR; X-ray powder diffraction, XRD), thermal (thermogravimetric analyzer, TGA; differential scanning calorimetry, DSC), and tensile properties. With 1.0-5.0 wt % additions of CNF to the PLA matrix, noticeable improvements in thermal and physical properties were observed for the resulting PLA/CNF biocomposites. The 2.5 wt % addition of CNF increased the tensile strength by 8.8%. The Tonset (initial degradation temperature) and Tmax (maximum degradation temperature) after adding 5.0 wt % CNF was increased by 20 °C, and 10 °C, respectively in the nitrogen atmosphere. These improvements were attributed to the good dispersibility and improved interfacial interaction of CNF in the PLA matrix.


Assuntos
Celulose/química , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/metabolismo , Nanofibras/química , Poliésteres/química , Poliésteres/metabolismo , Estrutura Molecular , Transição de Fase , Pressão , Relação Estrutura-Atividade , Propriedades de Superfície , Resistência à Tração , Temperatura de Transição
11.
J Sci Food Agric ; 99(10): 4624-4634, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30895624

RESUMO

BACKGROUND: Sweetpotato (Ipomoea batatas Lam.) is a major starchy crop with great agricultural significance in many countries. There is a need to assess more genetic resources for sweetpotato quality improvement. This study aims to analyze physicochemical properties of whole (unpeeled) root flours from seven New Zealand sweetpotato varieties with commercial significance. Using whole unpeeled plants for 'healthy' food formulations becomes more popular due to nutritional effects and environmental concerns. RESULTS: Great variations were found in chemical composition, in vitro antioxidant activities, swelling power, water solubility index, in vitro digestibility, thermal, pasting and gel textural properties of the seven flours. The antioxidant activities and phenolic contents were higher in the color-fleshed samples. Correlation analysis showed that the swelling, pasting and texture properties were largely affected by the activity of the endogenous amylase. Principal component analysis was done in four aspects including chemical composition, mineral content, antioxidant activities and functional properties to analyze the similarity and difference among these seven sweetpotato varieties. CONCLUSION: The seven sweetpotato flours showed a wide range of functionalities and will be useful for the formulations of diverse and 'healthy' sweetpotato-based products. © 2019 Society of Chemical Industry.


Assuntos
Farinha/análise , Ipomoea batatas/química , Amilases/química , Ipomoea batatas/classificação , Tubérculos/química , Solubilidade , Amido/química
12.
Small ; 14(20): e1800614, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29665299

RESUMO

The high aspect ratio and the porous nature of spatially oriented forest-like carbon nanotube (CNT) structures represent a unique opportunity to engineer a novel class of nanoscale assemblies. By combining CNTs and conformal coatings, a 3D lightweight scaffold with tailored behavior can be achieved. The effect of nanoscale coatings, aluminum oxide (Al2 O3 ) and nonstoichiometric amorphous silicon carbide (a-SiC), on the thermal transport efficiency of high aspect ratio vertically aligned CNTs, is reported herein. The thermal performance of the CNT-based nanostructure strongly depends on the achieved porosity, the coating material and its infiltration within the nanotube network. An unprecedented enhancement in terms of effective thermal conductivity in a-SiC coated CNTs has been obtained: 181% compared to the as-grown CNTs and Al2 O3 coated CNTs. Furthermore, the integration of coated high aspect ratio CNTs in an epoxy molding compound demonstrates that, next to the required thermal conductivity, the mechanical compliance for thermal interface applications can also be achieved through coating infiltration into foam-like CNT forests.

13.
Fire Saf J ; 952018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38567118

RESUMO

This paper presents a systematic investigation of the influence of various parameters on the thermal performance of composite floor slabs with profiled steel decking exposed to fire effects. The investigation uses a detailed finite-element modeling approach that represents the concrete slab with solid elements and the steel decking with shell elements. After validating the modeling approach against experimental data, a parametric study is conducted to investigate the influence of thermal boundary conditions, thermal properties of concrete, and slab geometry on the temperature distribution within composite slabs. The results show that the fire resistance of composite slabs, according to the thermal insulation criterion, is generally governed by the maximum temperature occurring at the unexposed surface of the slab, rather than the average temperature. The emissivity of steel has a significant influence on the temperature distribution in composite slabs. A new temperature-dependent emissivity is proposed for the steel decking to give a better prediction of temperatures in the slab. The moisture content of the concrete has a significant influence on the temperature distribution, with an increment of 1 % in moisture content leading to an increase in the fire resistance of about 5 minutes. The height of the upper continuous portion of the slab is found to be the key geometrical factor influencing heat transfer through the slab, particularly for the thin portion of the slab. Heat transfer through the thick portion of the slab is also significantly affected by the height of the rib and the width at the top of the rib.

14.
J Nanosci Nanotechnol ; 17(2): 1275-279, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29683302

RESUMO

This study investigated the structure and thermal, electrical, optical, and adhesive properties of two magnetic CoFeB thin films with compositions of Co40Fe40B20 and Co60Fe20B20.The thin films were deposited on a glass substrate by using direct current (DC) magnetron sputtering at room temperature (RT) and ranged in thicknesses from 25 to 200 Å. X-ray diffraction (XRD) patterns indicated that the thin films were amorphous. The activation energy (Q) of the Co40Fe40B20 and Co60Fe20B20 thin films exhibited concave up and concave down trends, respectively. The critical thickness of the films was 75 Å. The 75-Å-thick Co60Fe20B20 thin film exhibited the highest Q value, indicating that transforming the amorphous structure into a crystalline structure is difficult. When the Co concentration ratio was increased, the stability of the amorphous state of CoFeB increased apparently. The 75-Å-thick Co60Fe20B20 thin film exhibited the highest resistivity, whereas the 75-Å-thick Co40Fe40B20 thin film exhibited the lowest resistivity. As the thickness of the Co40Fe40B20 and Co60Fe20B20 thin films was increased, the transmittance decreased and absorbance increased. The Co60Fe20B20 thin film exhibited a higher surface energy and stronger adhesion than did the Co40Fe40B20 thin film.

15.
Sol Energy ; 146: 1-7, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28579647

RESUMO

A composite phase change material (PCM) comprised of organic montmorillonite (OMMT)/paraffin/grafted multi-walled nanotube (MWNT) is synthesized via ultrasonic dispersion and liquid intercalation. The microstructure of the composite PCM has been characterized to determine the phase distribution, and thermal properties (latent heat and thermal conductivity) have been measured by differential scanning calorimetry (DSC) and a thermal constant analyzer. The results show that paraffin molecules are intercalated in the montmorillonite layers and the grafted MWNTs are dispersed in the montmorillonite layers. The latent heat is 47.1 J/g, and the thermal conductivity of the OMMT/paraffin/grafted MWNT composites is 34% higher than that of the OMMT/paraffin composites and 65% higher than that of paraffin.

16.
J Food Sci Technol ; 54(7): 1891-1900, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28720945

RESUMO

During the processing of lemon fruit, a large quantity of seeds is produced as a by-product. These seeds contain valuable components; therefore, required to be evaluated. This study aimed to compare the cold pressed with hexane-extracted lemon seed oils and determine their physicochemical and thermal properties. Cold pressing yielded significantly lower oil (36.84%) than hexane extraction (71.29%). In addition, the concentrations of free fatty acids, peroxides, and p-anisidine were lower in the cold pressed oil. Cold pressed oil showed higher total phenolics, α-tocopherol and antioxidant capacity. The major fatty acids found in the cold pressed oil were linoleic and palmitic acids, whereas ß-sitosterol and campesterol were the dominant sterols. The crystallization and melting temperatures and enthalpies were also elucidated. In conclusion, this study proved that high quality of lemon seed oils can be produced by the cold pressing technique; this oil can be used in industries such as the food, cosmetic or chemical industries.

17.
J Insect Sci ; 14: 36, 2014 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-25373183

RESUMO

African wild silkmoth, Gonometa postica Walker (Lepidoptera: Lasiocampidae), were reared indoors in order to examine the influence of rearing conditions on the structure and properties of silk cocoon shells and degummed fibers by using a scanning electron microscope, an Instron tensile tester, and a thermogravimetric analyzer. The cocoons reared indoors showed inferior quality in weight, length, width, and cocoon shell ratio compared to cocoons reared outdoors. There were no differences in cocoon shell and fiber surfaces and cross sectional structures. Cocoon shells were covered with calcium oxalate crystals with few visible fibers on their surface. Degummed fibers were smooth with minimum unfractured surfaces and globular to triangular cross sections. Indoor-reared cocoon shells had a significantly higher breaking strain, while the breaking stress was higher for cocoons reared outdoors. Fibers from indoor cocoons had a significantly higher breaking stress while outdoor fibers had higher breaking strain. Thermogravimetric analysis curves showed two main thermal reactions revealing the dehydration of water molecules and ir-reversible decomposition of the crystallites in both cocoons and fibers reared indoors and outdoors. Cocoon shells underwent additional peaks of decomposition with increased temperature. The total weight loss was higher for cocoon shells and degummed fibers from indoors. Rearing conditions (temperature and relative humidity), feeding method used, changes in total life span, days to molting, and spinning might have influenced the variation in the properties observed.The ecological and commercial significances of indoor rearing of G. posticaare discussed.


Assuntos
Mariposas/química , Seda/química , Criação de Animais Domésticos , Animais , Feminino , Masculino , Mariposas/crescimento & desenvolvimento , Pupa/química
18.
iScience ; 27(4): 109460, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38550980

RESUMO

Various energy storage systems (ESS) can be derived from the Brayton cycle, with the most representative being compressed air energy storage and pumped thermal electricity storage systems. Although some important studies on above ESS are reported, the topological structure behind those systems (i.e., derivations of the Brayton cycle) has not been studied, and the underlying thermodynamic ideas still need to be further explored. This paper first introduces the topological structure and the symmetry of ESS and their based Brayton cycles. The formation method of ESS based on paths and separation points is specified. It is found that round-trip path can form ESS directly. Then various ESS formed are compared. Finally, the synergistic effect and gain principle of thermal cycle and ESS are revealed. This work helps to reveal the intrinsic relationship between thermal cycles and ESS, understand the general laws behind ESS, and guide the combination of thermal cycles and ESS.

19.
iScience ; 27(8): 110393, 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39108733

RESUMO

Symmetry analysis is a cutting-edge research approach in physics, yet its application in macroscopic energy systems remains limited. This study demonstrates its potential to provide valuable insights for a deeper understanding and development of thermodynamic cycles. This article first studies the symmetry of the proposed C-P diagrams and finds rich symmetries including reflection symmetry, translation symmetry, and rotational symmetry within Carnot cycles. Then, it emphasizes that one can use symmetry alone to prove that the highest efficiency for any cycle operating in a certain temperature range is the Carnot efficiency, without relying on the entropy concept in the second law of thermodynamics. Lastly, it is found that this symmetry analysis framework can also be used for thermal cycles with phase transitions, as exemplified by applying in Rankine cycles. This research not only contributes groundbreaking insights into unraveling the symmetry inherent in thermodynamic cycles, but also promotes symmetry analysis to be an alternative analysis mean.

20.
Plants (Basel) ; 13(19)2024 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-39409548

RESUMO

Balanced fertilizer application is crucial for achieving high-yield, high-quality, and efficient maize cultivation. Sulfur (S), considered a secondary nutrient, ranks as the fourth most essential plant nutrient after nitrogen (N), phosphorus (P), and potassium (K). S deficiency could significantly influence maize growth and development. Field experiments were conducted in Jiangsu, Yangzhou, China, from April 1 to July 20 in 2023. Jingkenuo2000 (JKN2000) and Suyunuo5 (SYN5) were used as experiment materials, and four treatments were set: no fertilizer application (F0), S fertilizer application (F1), conventional fertilization method (F2), and conventional fertilization method with additional S application (F3). The objective was to investigate the impact of S application on grain weight and the quality of fresh waxy maize flour and starch. The results indicated that all fertilization treatments significantly increased grain weight and the starch and protein contents in grains compared to no fertilization. Among these, F3 exhibited the most significant increases. Specifically, in JKN2000, the grain weight, starch content (SC), and protein content (PC) increased by 27.7%, 4.8%, and 14.8%, respectively, while in SYN5, these parameters increased by 26.3%, 6.2%, and 7.4%, respectively, followed by F2 and F1. Compared to F0, F3 increased starch and protein contents by 4.8% and 14.8% in JKN2000, and by 6.2% and 7.4% in SYN5. Compared to F0, F2 and F3 significantly increased the iodine binding capacity (IBC) of SYN5, with F3 being more effective than F2, while they had no significant effect on the IBC of JKN2000. The peak viscosity (PV) and breakdown viscosity (BD) of waxy maize flour and starch for both varieties showed a consistent response (increasing trend) to S application, and F3 had the largest increase. Regarding the thermal properties of waxy maize flour, F3 significantly enhanced the retrogradation enthalpy (ΔHgel) of both varieties compared to F0, while achieving the lowest retrogradation percentage (%R). In starch, the highest ΔHgel and the lowest %R were observed under the F2 treatment. In summary, under the conditions of this experiment, adding S fertilizer to conventional fertilization not only increased the grain weight of waxy maize but also effectively optimized the pasting and thermal properties of waxy maize flour and starch.

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