Your browser doesn't support javascript.
loading
Montrer: 20 | 50 | 100
Résultats 1 - 20 de 1.090
Filtrer
1.
Heliyon ; 10(16): e35910, 2024 Aug 30.
Article de Anglais | MEDLINE | ID: mdl-39224269

RÉSUMÉ

Fiber-reinforced polymer composites are preferred over conventional materials because of their superior strength and modulus. Previously limited due to high manufacturing costs, synthetic fibers have been replaced by some natural fibers, such as waste wheat straw fibers. Here, epoxy-based polymer composites' mechanical and physical properties have been investigated, focusing on fiber weight ratios for both treated and untreated fiber. The research found that treated fibers display more effective mechanical qualities than untreated fibers, with a higher tensile strength of 54.4 MPa. The untreated Wheat Straw-Glass fiber reinforced composite has a less tensile strength of 26.3 MPa (10 wt% fiber). Pure resin-based composite has the most minor tensile strength at 1.52 MPa. The highest flexural strength obtained for hybrid composite is 88.76 MPa for treated fiber with epoxy resin and 49.6 MPa for untreated 30 wt % fiber. At the same time, the sole epoxy resin composite has the lowest value of 10.60 MPa. Untreated fiber (30 wt%) has the highest impact energy of 8J. Untreated wheat straw fiber absorbs more water due to its hydrophilic nature. In contrast, treated fiber exhibits better bonding and minimal water content, and the sole epoxy resin composite exhibits hydrophobic properties, resulting in less water absorption. The treated fiber displays better bonding than the untreated fiber throughout the SEM analysis. Wheat Straw fiber is mainly used for biodegradable plastic formation, housing construction, building materials, etc.

2.
Sci Rep ; 14(1): 20816, 2024 Sep 06.
Article de Anglais | MEDLINE | ID: mdl-39242593

RÉSUMÉ

The impact of premade beef patty (BBP) with red onion skin powder (OSP) at 0, 1, 2, and 3% levels on color, lipid, and protein oxidative stability, and infection degree of microorganisms during cold storage was investigated. The objective was to determine the effect of color by L*, a*, b*, and the content of MetMb. The inhibitory effect of OSP on the oxidation of lipid and protein was studied based on TBARS and the carbonyl content of protein in samples at different storage times. TVB-N content was used to characterize the degree of infection of microorganisms and their effect on meat quality. The results showed that the addition of OSP reduced the pH, L *, a*, and b * values of BBP, and improved the hardness, springiness, gumminess, and cohesiveness of BBP, but had no significant effect on the chewiness of BBP (p > 0.05). After 12 days of storage, the carbonyl group and TBARS content in the BBP supplemented with 3%OSP was significantly lower than that in the control group (p < 0.05). Furthermore, the addition of OSP significantly inhibited the TVB-N increase during beef patty storage. These results indicated that OSP has a good research prospect as a natural antioxidant or preservative.


Sujet(s)
Couleur , Stockage des aliments , Oignons , Oxydoréduction , Oignons/composition chimique , Animaux , Bovins , Stockage des aliments/méthodes , Poudres , Lipides/composition chimique , Viande rouge/analyse , Substances réactives à l'acide thiobarbiturique/métabolisme , Substances réactives à l'acide thiobarbiturique/analyse , Basse température , Conservation aliments/méthodes
3.
Acta Bioeng Biomech ; 26(1): 121-132, 2024 Jun 01.
Article de Anglais | MEDLINE | ID: mdl-39219082

RÉSUMÉ

Purpose: Titanium alloys are among the most widely used materials in medicine, especially in orthopedics. However, their use requires the application of an appropriate surface modification method to improve their properties. Such methods include anodic oxidation and the application of polymer coatings, which limit the release of alloying element ions. In addition, biodegradable polymer coatings can serve as a carrier for drugs and other substances. The paper presents the results of research on the physical properties of biodegradable polymer coatings containing nanoparticle hydroxyapatite on a titanium alloy substrate. Methods: A PLGA coating was used in the tests. The coatings on the substrate of the anodized Ti6Al7Nb alloy were applied by ultrasonic spray coating. The tests were carried out for coatings with various hydroxyapatite content (5, 10, 15, 20%) and thickness resulting from the number of layers applied (5, 10, 15 layers). The scope of the research included microscopic observations using scanning electron microscopy, topography tests with optical profilometry, structural studies using X-ray diffraction, as well as wettability and adhesion tests. Results: The results shows that with the use of ultrasonic spray coating system is possible to obtain the continuous coatings containing hydroxyapaptite. Conclusions: The properties of the coating can be controlled by changing the percentage of hydroxyapatite and the number of layers of which the coating is composed.


Sujet(s)
Alliages , Matériaux revêtus, biocompatibles , Durapatite , Titane , Durapatite/composition chimique , Matériaux revêtus, biocompatibles/composition chimique , Titane/composition chimique , Alliages/composition chimique , Test de matériaux , Diffraction des rayons X , Mouillabilité , Polymères/composition chimique , Copolymère d'acide poly(lactique-co-glycolique)/composition chimique , Propriétés de surface
4.
Plant Foods Hum Nutr ; 2024 Sep 02.
Article de Anglais | MEDLINE | ID: mdl-39222224

RÉSUMÉ

The use of new types of raw materials to improve the quality and nutritional value of products is an important trend in flour confectionery. Flour from extruded sunflower seed kernels (FESSK), the by-product of oil production, was used as a new ingredient in muffin formulation. Analysis of physicochemical and nutritional properties of muffins prepared with FESSK, which was added in the amounts of 5, 10, and 15% to the total weight of mixture of wheat and rye flours, as well as their sensory evaluation, were performed. According to the sensory evaluation, the muffins with FESSK had a pleasant, nutty and sunflower aroma, and the best results were shown by muffins with 10% of FESSK. Addition of FESSK, 10%, led to an increase of the content of protein by 24.7%, fat by 16.9%, fiber by 23.3%, ash by 16.9%, and a decrease of content of total carbohydrates by 5.2% and sugars by 16.2%. Enriched muffins had improved texture characteristics, particularly, smooth, crack-free surface, soft, and elastic crumb with well-developed porosity and small, evenly distributed, thin-walled pores. The FESSK could be recommended as an ingredient for improving the nutritional and technological properties of flour confectionery products.

5.
Materials (Basel) ; 17(15)2024 Jul 26.
Article de Anglais | MEDLINE | ID: mdl-39124367

RÉSUMÉ

The construction industry's high energy consumption and carbon emissions negatively impact the ecological environment; large-scale construction projects consume much energy and emit a significant amount of CO2 into the atmosphere. Statistics show that 30% of energy loss and 40% of solid waste in the construction industry are generated during construction. Therefore, reducing emissions during construction has significant research potential and value. Many scholars have recently studied eco-friendly building materials to facilitate the use of high-carbon emission materials like cement. Adding fibers to composite materials has become a research hotspot among these studies. Although adding fibers to composite materials has many advantages, it mainly reduces the compressive strength of the composite material. This research used the response surface methodology (RSM) to optimize the raw material ratios and thus improve the performance of plant fiber composite materials. Single-factor experiments were conducted to analyze the effects of grass size, grass content, and quicklime content on the composite materials' compressive strength, flexural strength, and water absorption. The influencing factors and levels for the response surface experiment were determined based on the results of the single-factor analysis. Using the response surface methodology (RSM), a second-order polynomial regression model was established to analyze the interaction effects of the three factors on the composite materials' compressive strength, flexural strength, and water absorption rate. The optimal ratio was determined: the optimized options for grass size, grass content, and quicklime content are 2.0 mm, 8.2 g, and 38 g, respectively. The actual values of compressive strength, flexural strength, and water absorption rate of the composite materials made according to the predicted ratio are 11.425 MPa, 2.145 MPa, and 21.89%, respectively, with a relative error of 8% between the actual and predicted values. X-ray diffraction and scanning electron microscopy were also used to reveal the factors contributing to the relatively high strength of the optimized samples.

6.
J Clin Pediatr Dent ; 48(4): 160-167, 2024 Jul.
Article de Anglais | MEDLINE | ID: mdl-39087226

RÉSUMÉ

Glass ionomer cements (GICs) are the common materials employed in pediatric dentistry because of their specific applications in class I restorations and atraumatic restoration treatments (ART) of deciduous teeth in populations at high risk of caries. Studies show a limited clinical durability of these materials. Attempts have thus been made to incorporate nanoparticles (NPs) into the glass ionomer for improving resistance and make it like the tooth structure. An in vitro experimental study was conducted using the required samples dimensions and prepared based on the test being carried out on the three groups with or without the modification of light-cured glass ionomer. Samples were grouped as follows: control group (G1_C), 2% silver phosphate/hydroxyapatite NPs group (G2_SPH), and 2% titanium dioxide NPs group (G3_TiO2). The physical tests regarding flexural strength (n = 10 per group), solubility (n = 10 per group), and radiopacity (n = 3 per group) were performed. The data were analyzed by Shapiro Wilks test, and one-way analysis of variance (one-way ANOVA), and multiple comparisons by post hoc Tukey's test. The p-value of < 0.05 was considered significant. No statistically significant difference was observed between the control group (G1_C) and (G2_SPH) (p = 0.704) in the flexural strength test, however differences were found between G2_SPH and G3_TiO2 groups, ANOVA (p = 0.006); post hoc Tukey's test (p = 0.014). Pertaining to the solubility, G2_SPH obtained the lowest among the three groups, ANOVA (p = 0.010); post hoc Tukey's test (p = 0.009). The three study groups obtained an adequate radiopacity of >1 mm Al, respectively. The resin-modified glass ionomer cement (RMGIC) was further modified with 2% silver phosphate/hydroxyapatite NPs to improve the physical properties such as enhancing the solubility and sorption without compromising the flexural strength and radiopacity behavior of modified RMGIC. The incorporation of 2% titanium dioxide NPs did not improve the properties studied.


Sujet(s)
Durapatite , Ciment ionomère au verre , Nanoparticules , Phosphates , Titane , Titane/composition chimique , Ciment ionomère au verre/composition chimique , Durapatite/composition chimique , Nanoparticules/composition chimique , Phosphates/composition chimique , Techniques in vitro , Test de matériaux , Humains , Composés de l'argent/composition chimique , Solubilité , Résistance à la flexion
7.
Int J Food Microbiol ; 424: 110851, 2024 Nov 02.
Article de Anglais | MEDLINE | ID: mdl-39116463

RÉSUMÉ

The frozen fruit sector has experienced significant growth due to improved product quality as well as the advantage of long-term preservation. However, freezing alone does not eliminate foodborne viruses, a major public health concern and considerable economic burden. One promising disinfecting treatment is pulsed light, shown previously to inactivate hepatitis A virus (HAV) and murine norovirus-1 (MNV-1) on the surface of fresh berries. Viral loads were reduced by 1-2 log, with minor visual quality deterioration observed. In this study, an FDA-compliant pulsed light treatment (11.52 J/cm2) was applied to frozen fruits and berries. Infectious MNV-1 and HAV titers were reduced by 1-2 log on most frozen fruits. A noteworthy finding was that reductions of both viruses on cranberries exceeded 3.5 log cycles. Although pulsed light caused a measurable rise in temperature on the product surface, no visible physical changes (e.g., color) were observed, and the fruit pieces were still frozen after treatment. Although the reduction of infectious titer by pulsed light alone was not large (1-2 log), considering the low amount of virus typically found on fruit, it may be beneficial in the frozen fruit sector. It would be easy to combine with other treatments, and synergic interactions might increase virus inactivation.


Sujet(s)
Fruit , Virus de l'hépatite A , Norovirus , Inactivation virale , Norovirus/effets des radiations , Virus de l'hépatite A/effets des radiations , Virus de l'hépatite A/physiologie , Virus de l'hépatite A/croissance et développement , Inactivation virale/effets des radiations , Animaux , Lumière , Souris , Conservation aliments/méthodes , Microbiologie alimentaire , Congélation
8.
Nanomaterials (Basel) ; 14(15)2024 Jul 28.
Article de Anglais | MEDLINE | ID: mdl-39120369

RÉSUMÉ

The physical properties of nano-fertilizers (NFs) are important in determining their performance, efficacy, and environmental interactions. Nano-fertilizers, due to their small size and high surface area-to-volume ratio, enhance plant metabolic reactions, resulting in higher crop yields. The properties of nano-fertilizers depend on the synthesis methods used. The nanoparticle's nutrient use efficiency (NUE) varies among plant species. This review aims to analyze the relationship between the physical properties of NF and their influence on crop performance and nutrient uptake efficiency. The review focuses on the physical properties of NFs, specifically their size, shape, crystallinity, and agglomeration. This review found that smaller particle-sized nanoparticles exhibit higher nutrient use efficiency than larger particles. Nano-fertilizer-coated additives gradually release nutrients, reducing the need for frequent application and addressing limitations associated with chemical fertilizer utilization. The shapes of nano-fertilizers have varying effects on the overall performance of plants. The crystalline structure of nanoparticles promotes a slow release of nutrients. Amorphous nano-fertilizers improve the NUE and, ultimately, crop yield. Agglomeration results in nanoparticles losing their nanoscale size, accumulating on the outer surface, and becoming unavailable to plants. Understanding the physical properties of nano-fertilizers is crucial for optimizing their performance in agricultural applications.

9.
J Food Sci ; 2024 Aug 27.
Article de Anglais | MEDLINE | ID: mdl-39192687

RÉSUMÉ

The walnut cracking process is the most critical and delicate step for achieving high-quality kernels. The traditional method for cracking (manually) is labor-intensive, time-consuming, and tedious. The existing cracking approaches are low production efficiency and serious walnut kernel breakage. Increasing cracking efficiency with minimum kernel breakage has been a challenging issue in the preliminary processing of walnuts. Therefore, this study develops an innovative walnut cracker with self-grading and multi-station extrusion, combined with theoretical investigation and experiment verification. First, a statistical analysis of walnut physical properties was conducted, including dimensions, shell thickness as well as shape characteristics. The mechanical properties of walnut cracking were examined by a series of experiments. Based on mechanical theory, a grading mechanism was designed for preliminary processing before walnut cracking. Then a shaftless screw conveying mechanism and an extrusion cracking mechanism were developed. To evaluate the cracker's performance, a comprehensive examination was carried out. The experiments yielded impressive results, with a grading rate of 87.3%, a shell-breaking rate of 91.50%, and a kernel-exposed rate of 84.72%. These outcomes signify a substantial improvement in production efficiency while minimizing kernel breakage. The developed walnut cracker plays a crucial role in walnut processing and kernel extraction, thereby elevating economic value. PRACTICAL APPLICATION: A self-grading multi-station extrusion walnut cracker is developed, which includes a grading mechanism with a shaftless screw conveyor and a grid-type trommel screen for conveying and classifying walnuts. This cracker can adapt to different walnut varieties by changing the gap-adjusting guide to control the breaking gap. Compared to similar extrusion-type walnut crackers, the developed cracker not only incorporates preliminary classification but also exhibits superior performance. HIGHLIGHTS: A novel multi-station extrusion mechanism for walnuts cracking is developed. The cracker can accommodate various walnut sizes for self-grading and screening. The design with semi-arc plates converts extrusion force into alternating stress. The shell-breaking rate and kernel-exposed rate achieves 91.50% and 84.72%.

10.
Materials (Basel) ; 17(16)2024 Aug 16.
Article de Anglais | MEDLINE | ID: mdl-39203258

RÉSUMÉ

Nonwoven upholstery fabric is a waste product which is mainly generated during upholstered furniture production. The polyester composition makes it problematic to recycle and reuse this product. This study examined the manufacturing process of nonwoven fabric-reinforced plywood composites and their selected mechanical and physical properties. Nonwoven fabric was integrated between veneers bound with urea-formaldehyde resin to improve standard layered composites' mechanical and physical properties. Several board variants were produced, differing in the position of the nonwoven layers in the composite structure. The composites were evaluated for modulus of rupture (MOR), modulus of elasticity (MOE), internal bond, and screw withdrawal resistance, among others. The results showed that the addition of nonwoven fabric significantly improved some properties, like internal bond and screw withdrawal resistance. Variants with strategically placed nonwoven layers showed the highest performance increases. The results underscore the potential of nonwoven fabric as an effective reinforcing material, offering a path to developing high-performance plywood composites suitable for demanding applications. Another environmental advantage is that the nonwoven fabric waste used in the tested plywood production has not been subjected to burning or landfilling but, through its incorporation into plywood structure, has positively contributed to the Carbon Capture and Storage (CCS) policy. The findings advocate for a circular economy approach, in which industrial waste is effectively repurposed, contributing to the development of green materials in the wood-based composite industry.

11.
Food Res Int ; 192: 114804, 2024 Sep.
Article de Anglais | MEDLINE | ID: mdl-39147504

RÉSUMÉ

This study investigated spray drying a method for microencapsulating Lacticaseibacillus rhamnosus GG using a gastrointestinal resistant composite matrix. An encapsulate composite matrix comprising green banana flour (GBF) blended with maltodextrin (MD) and gum arabic (GA). The morphology of resulted microcapsules revealed a near-spherical shape with slight dents and no surface cracks. Encapsulation efficiency and product yield varied significantly among the spray-dried microencapsulated probiotic powder samples (SMPPs). The formulation with the highest GBF concentration (FIV) exhibited maximum post-drying L. rhamnosus GG viability (12.57 ± 0.03 CFU/g) and best survivability during simulated gastrointestinal digestion (9.37 ± 0.05 CFU/g). Additionally, glass transition temperature (Tg) analysis indicated good thermal stability of SMPPs (69.3 - 92.9 ℃), while Fourier Transform infrared (FTIR) spectroscopy confirmed the structural integrity of functional groups within microcapsules. The SMPPs characterization also revealed significant variation in moisture content, water activity, viscosity, and particle size. Moreover, SMPPs exhibited differences in total phenolic and flavonoid, along with antioxidant activity and color values throughout the study. These results suggested that increasing GBF concentration within the encapsulating matrix, while reducing the amount of other composite materials, may offer enhanced protection to L. rhamnosus GG during simulated gastrointestinal conditions, likely due to the gastrointestinal resistance properties of GBF.


Sujet(s)
Préparation de médicament , Gomme arabique , Lacticaseibacillus rhamnosus , Musa , Polyosides , Poudres , Probiotiques , Séchage par pulvérisation , Lacticaseibacillus rhamnosus/composition chimique , Gomme arabique/composition chimique , Polyosides/composition chimique , Musa/composition chimique , Taille de particule , Capsules , Farine/analyse , Spectroscopie infrarouge à transformée de Fourier , Digestion , Viscosité , Tube digestif/métabolisme , Viabilité microbienne
12.
Sci Rep ; 14(1): 15995, 2024 Jul 10.
Article de Anglais | MEDLINE | ID: mdl-38987292

RÉSUMÉ

This paper focuses on the effect of granite-micro-filler on static mechanical properties, damping behavior, and physical characteristics of silk-sisal hybrid composite. The composites structures are fabricated by using three layers of plain weaves mat with varying weight percentages (2, 4, and 6 wt%) of granite-micro-filler by hand layer process. The effect of granite-micro-filler on silk-sisal is analyzed and results are compared with pure silk-sisal (without granite-Micro-filler) hybrid composite. The results infer that; the tensile strength and flexural strength value of the developed silk-sisal hybrid composites are increased with the increase in wt% of granite-micro-filler content than pure silk-sisal, approximately 5% and 9% improved value in order by adding 6 wt% granite-micro-filler on silk-sisal. The tensile and flexural fracture morphology analysis indicated that composed plain weave of silk-sisal fiber mat with two (longitudinal and transverse) directions possesses higher mechanical properties and also observed that, granite-micro-filler dispersed on silk-sisal fiber mat and resin with closely packed. The improved damping factor is obtained by adding 6 wt% of granite-micro-filler content, which is approximately 75.8% higher than pure silk-sisal. The physical properties of silk-sisal hybrid composite have also been analyzed and well discussed in this paper.

13.
Rev Cient Odontol (Lima) ; 12(1): e188, 2024.
Article de Anglais | MEDLINE | ID: mdl-39015310

RÉSUMÉ

Objective: To describe the existing knowledge about metal-free prosthetic biomaterials according to their physicochemical properties and based on this, define criteria for their placement in both the anterior and posterior sectors. Materials and methods: A digital search was carried out in the databases: PubMed/Medline, Scopus, Web of Science and Google Scholar of the literature published in the English language without time restrictions and included original articles such as case reports, retrospective and prospective studies, narrative, comprehensive, systematic reviews and meta-analysis. Meanwhile, short communications, editorials and articles in a language other than English were excluded. Results: 40 articles were evaluated, published between 2000 and 2023. The main characteristics and physicochemical properties of ceramic biomaterials such as zirconia, feldspathic based ceramics, lithium disilicate and alumina, among others, were analyzed and summarized. In addition, certain criteria were defined based on the available scientific evidence on the use of different ceramic systems both in the anterior sector and in the posterior sector for patients who need some type of prosthetic restoration. Conclusions: Among the different metal-free materials used for the construction of fixed dental prostheses, zirconia has been shown to have better aesthetic, biomechanical and biocompatibility properties, which makes it a candidate material for the rehabilitation of partially edentulous patients.


Objetivo: Describir el conocimiento existente sobre los biomateriales protésicos libres de metal, según sus propiedades fisicoquímicas, y definir, con base en ello, criterios para su colocación tanto en el sector anterior como en el posterior. Materiales y métodos: Se realizó una búsqueda digital en las bases de datos PubMed/Medline, Scopus, Web of Science y Google Scholar de la literatura publicada en idioma inglés, sin restricciones de tiempo. Se incluyó artículos originales como reportes de casos, estudios retrospectivos y prospectivos, revisiones y metanálisis narrativos, exhaustivos y sistemáticos. Por otra parte, se excluyeron comunicaciones breves, editoriales y artículos en idioma distinto al inglés. Resultados: Se evaluaron 40 artículos, publicados entre 2000 y 2023. Se analizaron y resumieron las principales características y propiedades fisicoquímicas de biomateriales cerámicos, como circonia, cerámicas de base feldespática, disilicato de litio y alúmina, entre otros. Además, se definieron ciertos criterios basados en la evidencia científica disponible sobre el uso de diferentes sistemas cerámicos, tanto en el sector anterior como en el posterior, para pacientes que necesitan algún tipo de restauración protésica. Conclusiones: Entre los diferentes materiales libres de metales utilizados para la construcción de prótesis dentales fijas, la circonia ha demostrado tener mejores propiedades estéticas, biomecánicas y de biocompatibilidad, lo que la convierte en un material candidato para la rehabilitación del paciente parcialmente edéntulo.

14.
Ultrason Sonochem ; 108: 106978, 2024 Aug.
Article de Anglais | MEDLINE | ID: mdl-38971086

RÉSUMÉ

Drying, as a critical step in the production of air-dried beef, has a direct impact on the quality of the final product. Innovatively, a composite system incorporating contact ultrasound (CU) and infrared radiation (IR) as auxiliary measures within a hot air drying (HAD) framework was built in this research, and the effects of these techniques on the drying kinetics, protein denaturation, and moisture transformation of air-dried beef were investigated. In comparison to HAD treatment, the integrated CU and IR (CU-IRD) system displayed marked enhancements in heat and moisture transport efficiency, thereby saving 36.84% of time expenditure and contributing favorably to the improved moisture distribution of the end-product. This was mainly ascribed to the denaturation of myosin induced by IR thermal effect and the micro-channel produced by CU sponge effect, thus increasing T2 relaxation time and the proportion of free water. In conclusion, the composite system solved the problem of surface hardening and reduces hardness and chewiness of air-dried beef by 40.42% and 45.25% respectively, but inevitably increased the energy burden by 41.60%.


Sujet(s)
Air , Dessiccation , Rayons infrarouges , Eau , Eau/composition chimique , Cinétique , Dessiccation/méthodes , Bovins , Animaux , Ondes ultrasonores , Température élevée , Viande rouge , Phénomènes physiques
15.
Polymers (Basel) ; 16(14)2024 Jul 10.
Article de Anglais | MEDLINE | ID: mdl-39065288

RÉSUMÉ

In this study, a twin-screw extruder was used to fabricate poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends and blend-based nanocomposites with carbon nanotube (CNT) or nanocarbon black (CB) as nanofillers. The fabricated samples were subsequently treated with supercritical carbon dioxide (scCO2) to fabricate the corresponding foams. Bi-phasic morphology and selective distribution of CNTs or CBs in the PBAT phase were observed in the blends/composites through scanning electron microscopy. After the scCO2 treatment, the selective foaming of the PBAT phase in the prepared blends/composites was confirmed. The cellular structure of PBAT phase in scCO2-treated blends is similar to the size/shape of PBAT domains in untreated blends or treated neat PBAT foam. The addition of CNTs or CBs in the blends led to a slight reduction in cell size of the foamed PBAT phase, demonstrating CNT/CB-induced cell nucleation. Differential scanning calorimetry (DSC) results showed that CNTs and CBs played as nucleating agents and increased the initial crystallization temperature up to 14 °C compared with neat PBAT for PBAT in different composites during cooling. The scCO2 treatment induced the bimodal stability of PBAT crystals in different samples, which melted mainly in two temperature regions in DSC studies. Thermogravimetric analyses revealed that compared with parent blends, the addition of CNTs or CBs increased the temperature at 80 wt.% loss (degradation of PBAT portion) up to 6 °C. The electrical resistivity decreased by more than six orders of magnitude for certain CNT- or CB-added composites compared with the parent blends. The hardness of the blends slightly increased after forming the corresponding composites and then declined after the scCO2 treatment.

16.
Polymers (Basel) ; 16(14)2024 Jul 14.
Article de Anglais | MEDLINE | ID: mdl-39065329

RÉSUMÉ

High-strength concrete (HSC) has a high compressive strength, high density, excellent durability, and seepage resistance, but its deformation ability is weak. Adding fibers can improve the physical and mechanical properties of HSC. Additionally, the HSC structure may face the threat of fire. In the process of fire extinguishing, the damage mechanism of high-temperature-resistant concrete is complicated due to the different contact conditions with water at different locations. Hence, it is essential to conduct pertinent research on the behavior of fiber-reinforced HSC with different cooling methods after high-temperature action. In this paper, polyvinyl alcohol fiber (PVA fiber) was selected to be added into the HSC to carry out high-temperature experimental research, so as to explore the apparent changes, failure pattern, and mass loss rate of the fiber-reinforced HSC using different cooling methods and analyze the influence of its residual compressive strength and flexural strength. The test results suggest that, with the increase in heating temperature, the color of the specimen's surface transitions from dark blue-gray to white, and the quantity of surface cracks on the specimen gradually rises. The mechanical strength gradually decreases as the heating temperature increases. At a consistent heating temperature, the mechanical strength initially rises, and then falls with an increase in fiber content. The maximum compressive strength and flexural strength were achieved at PVA fiber contents of 0.2% and 0.3%, respectively. For different temperatures and fiber contents, the mechanical strength after natural cooling is generally higher than that after immersion cooling. In addition, X-ray polycrystalline diffractometry (XRD) and scanning electron microscopy (SEM) tests were conducted to analyze the compositional alterations and microstructure of the fiber-reinforced HSC following high-temperature exposure, accompanied by an explanation of the factors influencing the alterations in the physical and mechanical properties. Therefore, the findings of this study can serve as a valuable reference for the utilization of HSC in engineering structures and contribute to the advancement of HSC technology.

17.
Sci Rep ; 14(1): 16606, 2024 07 18.
Article de Anglais | MEDLINE | ID: mdl-39025936

RÉSUMÉ

The agronomic use of compost and biochar as soil amendments may exhibit contrasting results in terms of soil fertility and plant nutrition. The effects of the biennial application of biochar, compost and a blend of compost:biochar (90:10; % dw:dw) on the agronomical performance of an organically managed and well established 25-year-old olive orchard was assessed 5 years after the initial application. The agronomical evaluation was based on the assessment of the soil physical, chemical, and biological characteristics, and the assessment of the soil fertility by both crop production and nutritional status of the orchard, and the bioassay with olive plantlets. Biochar mainly benefited the physical properties (bulk density, total porosity, aeration, water retention capacity) of soil, especially in the top 0-5 cm. Compost and its blend with biochar improved microbial activity, soil nutritional status (increasing the content of soluble organic C, N, and P) and favoured the formation of aggregates in soil. The bioassay conducted with young plantlets confirmed the enhanced soil fertility status in the three amended treatments, particularly in the case of biochar and its blend with compost. However, this effect was not significantly observed in the adult plants after 5 years of application, reflecting the slow response of adult olive trees to changes in fertilization. Based on these results, alongside the desirable long-residence time of biochar in soil and the ready availability of compost, the blend of biochar with compost assayed in this study is defined as a valid strategy for preparing high quality soil organic amendments.


Sujet(s)
Charbon de bois , Compostage , Olea , Sol , Olea/croissance et développement , Sol/composition chimique , Compostage/méthodes , Engrais/analyse , Agriculture biologique/méthodes
18.
J Funct Biomater ; 15(7)2024 Jun 25.
Article de Anglais | MEDLINE | ID: mdl-39057295

RÉSUMÉ

This review article will discuss the origin of resin-based dental composite materials and their adoption as potentially useful adjuncts to the primary material used by most dentists for direct restorations. The evolution of the materials, largely driven by the industry's response to the needs of dentists, has produced materials that are esthetic, strong, and versatile enough to be used in most areas of the oral cavity to replace or restore missing tooth structures. Significant advancements, such as the transition from chemical to light-curing materials, refinements in reinforcing particles to produce optimum polishing and wear resistance, formulating pastes with altered viscosities to create highly flowable and highly stiff materials, and creating materials with enhanced depth of cure to facilitate placement, will be highlighted. Future advancements will likely reflect the movement away from simply being a biocompatible material to one that is designed to produce some type of beneficial effect upon interaction within the oral environment. These new materials have been called "bioactive" by virtue of their potential effects on bacterial biofilms and their ability to promote mineralization of adjacent tooth structures.

19.
Nanomaterials (Basel) ; 14(14)2024 Jul 12.
Article de Anglais | MEDLINE | ID: mdl-39057863

RÉSUMÉ

NaNbO3(NN)-based lead-free materials are attracting widespread attention due to their environment-friendly and complex phase transitions, which can satisfy the miniaturization and integration for future electronic components. However, NN materials usually have large remanent polarization and obvious hysteresis, which are not conducive to energy storage. In this work, we investigated the effect of introducing CaTiO3((1-x)NaNbO3-xCaTiO3) on the physical properties of NN. The results indicated that as x increased, the surface topography, oxygen vacancy and dielectric loss of the thin films were significantly improved when optimal value was achieved at x = 0.1. Moreover, the 0.9NN-0.1CT thin film shows reversible polarization domain structures and well-established piezoresponse hysteresis loops. These results indicate that our thin films have potential application in future advanced pulsed power electronics.

20.
J Food Sci Technol ; 61(9): 1662-1674, 2024 Sep.
Article de Anglais | MEDLINE | ID: mdl-39049924

RÉSUMÉ

The optimization of hydration temperature and duration were determined in six basmati and non-basmati paddy cultivars varying in grain size, shape, and amylose content based on kinetic parameters and effect of hydration temperature on physical, milling, textural and color attributes. Based on higher R2, lower Chi square and RMSE values, Peleg model fitted more suitably compared to Singh and Kulshrestha model. Hydration process significantly altered geometric, gravimetric and mechanical properties as evident by regression analysis. Physical properties except length and L/B ratio positively correlated with increasing hydration temperature. Head rice yield significantly improved in the hydrated treatments and showed a linear increase with the increase in hydration temperature. Head rice yield significantly correlated with hardness of grain (r = 0.684, p ≤ 0.01). Variable physico-chemical properties of cultivars led to establishment of cultivar specific optimum hydration temperature. Based on improvement in hardness, milling efficiency, head rice yield, color and textural attributes, the optimized temperature emerged as 75 °C for long slender grained cultivars (PB1509, PB1718, PS17) and 80 °C for medium grained cultivars (PD18, KJ, AL). The results revealed that optimum hydration temperature should be cultivar specific to get better output of parboiling process. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-024-05925-1.

SÉLECTION CITATIONS
DÉTAIL DE RECHERCHE