Bioinspired ceramics based on the nacreous part of the mother-of-pearl microstructure have been developed in recent years to produce materials with high mechanical performance. Although significant ...advances in terms of simplicity and scalability of the synthesis process have been achieved, the reasons behind the improvement of the mechanical properties remains to be pinpointed. Recently, the development of boron containing nacre-like refractories have offered new insights into the relationship between the interphase composition and the performance increase of nacre-like materials. Based on those achievements, this paper presents a multiscale analysis to evaluate the role of the refractory interphase on the mechanical properties of the nacre-like refractories. The results demonstrate the presence of increased residual stresses and adhesion between the alumina platelets induced by the aluminium borate second phase when compared to composition without secondary phase. These new findings provide additional information towards a better design and fabrication of high-performance nacre-like refractories.
Steel ladle refractory lining plays an important role in steelmaking refinement as its thermal properties are strictly related to the ladle ability to keep the molten steel temperature constant. This ...work developed a transient numerical analysis, considering temperature dependent refractory properties. A holistic view of the process was proposed to help the refractory design of steel ladles, according to their saving energy capability and overall costs. The numerical description of the ladle cycle used the finite element method (FEM) via commercial software (Abaqus). The average heat flux in the hot face while holding the liquid steel determined the steel ladle energy losses and was compared to evaluate the lining efficiency. The investigations considered the application of distinct working refractories and the presence of an insulating layer. The developed thermal and energy balance tool provided a more inclusive and integrated approach for investigating the energy consumption and thermal history of the steel ladle process, regarding the refractory lining design.
•Microsilica increase mechanical properties without affect acoustic properties.•Higher microsilica percentage, impact in a porosity smaller.•With 5% of microsilica, better is the thermal ...conductivity.•It is possible to obtain a 87.85% of porosity with 0.20% of microsilica.
Gypsum is an ancient material of great abundance that can be used as acoustic and thermal insulation protection in civil construction, especially when water-based foam is added to it, improving these properties. This research presents gypsum foam processing using a direct casting method with additives from natural sources, thus avoiding environment degradation. The results showed that gypsum foam has a potential for thermal and acoustic insulation and is more effective than other materials currently being used. Although, the material mechanical strength decreases when only water-based foam is added, further microsilica (MS) addition improved its mechanical strength without spalling its acoustic absorption and thermal conductivity.
The objective of this study was to evaluate the effect of different trace mineral supplementation sources in the diet of broiler breeders on their performance and on their progenies. In total, 128 ...Cobb 500 broiler breeders were distributed according to a completely randomized experimental design in 2 experimental treatments. The control group was fed a diet supplemented with inorganic trace minerals (ITM), while the other group was fed a diet supplemented with reduced levels of trace minerals in the organic form. Eggs were collected when breeders were 35, 47, and 53 wk old. Their progeny (450 hatchlings) were divided according to trace mineral supplementation source from the maternal diet, creating 2 treatments with 16 replicates of 15 birds each. Organic trace mineral (OTM) supplementation improved broiler breeder performance, as shown by higher egg production and better eggshell quality of OTM-fed hens compared with those fed ITM. Egg fertility and hatchability were not influenced by the treatments. As to progeny performance, higher weight gain, and consequently, better feed conversion ratio, were obtained in the 41-day-old progenies of OTM-fed breeders, independently of hen age. Maternal diet trace mineral source did not affect broiler carcass, breast meat, or leg yields. The results of the present study show that supplementing broiler breeder diets with organic trace mineral sources enhances the performance of breeders and their progenies.
High-temperature ceramics, so-called refractories, are widely used for the manufacturing of metals, for energy generation and aerospace applications. Refractories are usually strong and stiff but ...fragile due to the lack of plastic deformation and other intrinsic toughening mechanisms. This inherent brittleness limits their use in applications where catastrophic failure is not tolerated. The present work reports the design and fabrication of refractories with a bio inspired nacre-like microstructure comprising aligned alumina platelets, separated by an aluminium borate interphase, obtained through transient liquid phase sintering. The bioinspired composites exhibit high strength, 672MPa, toughness, 7.4MPam1/2, and stable crack propagation at high temperatures, above 600°C, due to the aluminium borate interlayer. This makes nacre-like ceramic refractories sintered with a transient liquid phase good candidate for high temperature applications, competing favourably with ceramic matrix composites and following a simpler and cheaper processing route.
Materials selection of multi-component systems is a challenging task, which is usually not properly tackled in furnace linings (FL) design. In an attempt to generate a systematic approach to select ...FL ceramic materials, an evolutionary screening procedure (ESP) is proposed in this paper, where a multi-objective genetic algorithm coupled with a finite element model aims to transform a list of potentially feasible ceramic candidate materials into an optimized set of multi-component systems simultaneously computing external lining temperatures and costs. An ESP-based selection methodology is proposed and studied in light of a case-study concerning an electric resistance furnace. A customized initial screening was carried out to select potential single candidate materials to be used. Next, the ESP was used to select optimized lining configurations while discarding infeasible combinations, such as those in which one of the materials maximum allowed temperature had been breached. Afterwards, TOPSIS (a multi-criteria decision-making approach) was applied to rank the optimized results according to some furnace preference scenarios. The ESP-based selection diminished a universe of 1.9×105 lining configurations into a few units to be investigated in more details by simulating only 3.8% of them, thus requiring reduced amount of time for completing this task. The adopted quantitative strategy uses commonly used computational techniques and could be applied to metallurgical ladle linings, be adapted to select raw materials or resolve other complex decision-making problems in the ceramic community.
The refractory field is a complex network in which long-term trends are determined based on the interaction between different players such as raw material producers, refractory manufacturers, end ...users, research centres and universities. As it is a complex system, it is very difficult to know who the leading participants are in the scientific development and what the future technologies and trends will be in the area. In order to retrieve this information, data mining and the graph theory were used to analyse publications from the major technical journals in the refractory area over the last 21 years. Based on this study, a complete map of the international collaboration of the different leading countries in the refractory field was attained. A common factor of these countries is the active working interaction, which helps them to tackle challenging problems with a high degree of complexity. In depth, technological trends were obtained from the analysis of selected keyword over the period considered showing a lack of technological breakthrough in the past 10 years. Furthermore, a strong increasing trend using different types of computer simulations to support the technological development of the refractories was observed.
This study investigated the chemical composition, immunomodulatory and antioxidant activities, and histopathological analysis of mice tissues treated with methanolic extract from R. marina poison. ...Marinobufagin, telecinobufagin and bufalin were identified in the chemical profile. The biochemical results demonstrated an effect between doses in the period of 7 days, an immunomodulatory effect was observed regarding the production capacity of interleukin (IL)-12p70 and tumor necrosis factor (TNF)-α at 7 and 30 days, respectively. The lower dose suggests better bioactivity to the treated animal than the higher dose. Histopathological analyses of the lung, heart, kidney and liver showed tissue damage in all organs, mainly in the lung, and were proportional to the dose and the treatment period. We observed that the treatment modulated cytokine production, and therefore this effect may be related to the tissue damage observed. This study demonstrates a positive effect in the antioxidant and immune system, indicating that the molecules found in the extract have biotechnological potential.
ABSTRACT
Considering the market availability of new commercial layer strains with distinct characteristics and behaviors, studies to update their nutritional requirements and to evaluate the need to ...adopt management practices, such as beak trimming, are needed. The objective of the present study was to evaluate the effects of dietary metabolizable energy (ME) levels and beak trimming on the live performance, egg quality, and economics of commercial layers. A total of 640 Novogen White layers were distributed according to a randomized experimental design in a 5 × 2 factorial arrangement (5 ME levels × 2 beak trimming treatments), totaling 10 treatments with 8 replicates of 8 hens each. The evaluated dietary ME levels were 2,600; 2,700; 2,800; 2,900; and 3,000 kcal/kg of feed. Layers were beak-trimmed once (7 days old) or twice (7 and 70 days old). Live performance and egg quality mesuraments and production economics were analyzed. Egg production was positively influenced by dietary ME levels. Feed intake (FI), feed conversion ratio (FCR), egg weight, albumen height, Haugh units, and eggshell strength were positively influenced by increasing dietary ME levels. Hens beak-trimmed once presented higher feed intake and worse FCR than those beak-trimmed twice. Beak trimming did not affect egg production, egg weight, albumen height, Haugh units, and eggshell strength. Production costs increased as dietary ME levels increased. Higher production cost was determined for hens beak-trimmed once than for those beak-trimmed twice. Total revenue was not influenced by the treatments. Gross margin was linearly decreased as dietary ME levels increased and was lower when hens were beak-trimmed once. Increasing dietary ME levels and beak trimming hens once reduce the economic viability of egg production.
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