Abstract In Brazil, the production of each ton of steel generates approximately 621 kg of waste and direct co-products. One of the components that generates a high amount of waste is the refractory material used in the steel process. So, in this study, the possibility of using MgO-C refractory waste from steel casting pots after their deterioration for the formation of chemically bonded phosphate ceramics was investigated. This work aims to study the recovery of industrial solid waste from MgO-C refractories by determining the processing conditions necessary to obtain magnesium phosphate ceramics. Three mean particle size of the waste and three potassium monophosphate:MgO ratio in the mixture were adopted. All mixtures showed the formation of the K-struvite phase and a strong relationship between the compressive strength and porosity properties. The highest compressive strength value obtained, 7.51 ± 0.24 MPa, is sufficient for use in several areas of engineering. It was also possible to statistically represent, using a quadratic model, the variation in porosity in relation to the phosphate content and particle size of the waste, obtaining porosities ranging from 14% to 25%. Taking into account this study used a waste, the evaluation of its environmental impact assumed an important role. The waste showed no appreciable toxicity, while some samples W3-20 showed toxicity to Allium cepa L. and Artemia salina. Considering the presented properties, the obtained material could be used as a structural block, filters, support for catalysts, and repair element for cement-based structures and roadways.

Abstract This study aims to evaluate the influence of the 11.6Li2O-16.8ZrO2-68.2SiO2-3.4Al2O3 (mol%) glass-ceramic addition (LZSA, 7 to 21 vol%) on the erosive wear of alumina in comparison to values of pure alumina obtained from the literature. Thus, composites were prepared from three commercial alumina of different initial particle sizes. Specimens were obtained by uniaxial pressing. Sintering temperatures and holding times were found to be different for each composite. The erosive wear test was carried out in an apparatus based on the standard ASTM G 76-4. The volumetric erosive wear (T vol) was correlated to the initial mean particle size of alumina, LZSA glass-ceramic content, average grain size of sintered alumina (AGS), porosity (P), elastic modulus, fracture toughness, natural defect size, and fracture energy based on a correlation matrix of statistical analyses. The experimental data of Tvol fit very well with P and AGS, individually, in a 3rd degree equation, except for composite AF21. Composite AF21, i.e. 21 vol% LZSA added to 0.5 µm mean particle size alumina (AF, fine alumina) and sintered at 1470 oC for 3 h, showed interesting results of T vol(2.05 × 10-8 m3·kg-1) related to the other investigated compositions, which varied from 1.90-4.37 × 10-8 m3·kg-1, and those existing in literature (0.55 × 10-8 to 10.78 × 10-8 m³·kg-1), mostly when considering the lower sintering temperature (1470 against 1600 oC). Thus, although the AC7 composite had shown the lowest Tvol value (1.90 × 10-8 at 1600 oC/7 h), the composite AF21 can be considered as the best result because of its lower sintering temperature and holding time (2.05 × 10-8 at 1470 oC/4 h). The formation of a viscous liquid phase, which crystallizes during the controlled cooling in the microstructure of the LZSA/alumina-based composites, improves the erosive wear of the alumina.

RESUMO Polyols as solvents are widely and successfully used in various methodologies to obtain zinc oxide nanostructures. One of the main reasons of using polyols is related to its capacity to prevent the agglomeration of ZnO nanoparticles during the synthesis and to promote a more stable colloidal solution of it. In this work it is presented, for the first time, the obtaining of nanostructured ZnO by a polyol mediated solvothermal synthesis using zinc nitrate as precursor. The combination of the zinc source with sodium hydroxide in a polyol medium with PVA as dispersing agent provided a simple process for obtaining nanostructured ZnO. The zinc oxide nanostructures obtained were characterized by UV-visible, XRD, FESEM, TEM, DLS and BET. As result, was obtained a wurtzite phase with hexagonal structure with crystallite size of 12 nm and, according to TEM micrographs, an average size of 14 nm, which was corroborated to other analyses.

Abstract The clay minerals have characteristics and properties that allow their applicability in the cosmetic area, being incorporated into formulations as an active principle. Therefore, the aim of this work is characterizing and evaluating the influence of a clay from Miracema do Norte, Tocantins, Brazil, named Clay V, on the physicochemical characteristics of a hydrophilic gel of Aristoflex®, a copolymer of the neutralized acryloyldimethyltaurate and vinylpyrrolidone sulphonic acid. Clay V was decontaminated and characterized through microbiological evaluation, crystalline phases present by X-Ray Diffraction (XRD), chemical composition by X-Ray Fluorescence (XRF), thermogravimetric analysis (TGA) and granulometric distribution by sieving. Gels were prepared using Clay V with particles in the range ≤ 180 μm in three different concentrations: 1%, 3% and 5% (w/w) and a standard gel without clay. The formulations were evaluated according to organoleptic characteristics, pH, viscosity, spreadability and the centrifugation test. The microbiological evaluation showed that the clay sample is in compliance with the parameters established by the legislation. The following mineral phases were identified by XRD: kaolinite, illite, vermiculite and quartz, mainly composed of silica and alumina according to XRF. Thermal analysis showed that the clay has two thermal decomposition reactions, the largest being 547.6°C. The granulometric analysis identified that the largest fraction (63.22%) was of particles with sizes greater than 710 μm. The organoleptic characteristics presented by the formulations were suitable, with characteristic gel odor, homogeneous appearance, soft and refreshing texture and staining based on the concentration of Clay V used. The obtained pH values were within the range between 5.5 and 6.5, and it was verified that the gel has high spreadability, distributing evenly on the skin. The values obtained for viscosity showed that the formulations are non-Newtonian fluids with pseudoplastic behavior. The centrifugation test showed that the formulations are stable, with no phase separation. The results obtained with the tests showed that the natural clay V material is beneficial in cosmetic products and can be used for incorporation in cosmetic gel formulations of Aristoflex® type.

Oil is a major pollutant of water resources, affects aquatic life, causing environmental degradation. Currently there is an increase in studies of membrane applied to separation of oil-water. Among these membranes, there are composite membranes, which show as main characteristic an association of organic and inorganic membrane properties. In a tangential flow process, the ceramic tube (support) is responsible for the mechanical strength of the membrane and the selective barrier property of the membrane is established by the polymer. The aim of this work is the application of α-alumina/polyamide 66 composite membrane in the retention of sunflower oil from oil-water emulsions and the study of resistance of such membranes in ultrafiltration processes. The α-alumina ceramic tubes were impregnated internally with a solution of polyamide 66 (PA66) (5% w/v) and tested with distilled water and sunflower oil solutions at concentrations of 50, 100 and 200 mg·L-1. Membranes impregnated with PA66 showed a sunflower oil retention between 53.5 and 99.5% and superior membrane resistance (MR) to the permeate flux (1.92 x 1013 a 5.52 x 1013) which explains the decrease in the permeate volume.

Water pollution by organic compounds is one of the major challenges faced by industries that use dyeing processes. Thus, some methods were developed for degrading dyes in wastewaters, including heterogeneous photocatalysis by semiconductor oxides. However, these oxides have limited photocatalytic activity due to the fast recombination of photogenerated electron-hole pairs. The aim of this study is the use of a carbon nanotube (CNT) and TiO2-ZnO oxide junction from modified sol-gel method to promote the degradation of organic dye through the photocatalytic activity of these nanocomposites. TiO2-ZnO/CNT nanocomposites were studied by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM) and photocatalytic decomposition of organic dyes. The results of photocatalysis show up to 60% the efficiency of the samples in the removal of dye.

In this study, polymer/ceramic composite membranes were prepared and characterized. The polymer used was polyamide 66 (PA66) deposited by dip coating on the inner surface of α-alumina-based (Al2O3) microporous tube. A coating on the ceramic support surface and the formation of the selective layer was analyzed by scanning electron microscopy (SEM) in membranes with one (PA-1) and two layers (PA-2). The results of mercury porosimetry showed that the deposition of the polyamide layers decreases the average pore size. The PA-1 presented an average pore size of 0.35 μm, while the PA-2 presented two peaks of 0.18 and 0.56 μm. Both showed a superior performance than the ceramic support (pore diameter of 0.65 μm). Although, the permeate flux was higher with an impregnation membrane, the number of layers (one or two) just introduced a slight difference in pore statistical analysis. The order of rejection coefficient values for protein molecules is BSA > egg albumin > trypsin. The permeation tests showed that the composite membrane can be applied in ultrafiltration processes with MWCO of 69 kDa.

RACIONAL: No tratamento cirúrgico do câncer colorretal, a linfadenectomia é considerada adequada quando pelo menos 12 linfonodos são removidos. OBJETIVO: Avaliar se a operação videolaparoscópica afeta positivamente as taxas de linfadenectomia adequada. MÉTODOS: Estudo observacional foi realizado com pacientes submetidos à operação aberta ou videolaparoscópica para câncer colorretal entre 2008 e 2013. As seguintes variáveis foram coletadas: gênero, idade, localização do tumor, histologia, grau de diferenciação, estágio do tumor, número de linfonodos removidos , e número de nódulos linfáticos afetados pela doença. RESULTADOS: Um total de 62 pacientes com câncer colorretal foram incluídos; 42 (67,7%) receberam operação aberta e 20 (32,3%) laparoscópica. Quanto à linfadenectomia, média de 13 nódulos linfáticos (95% CI: 10-16) foram removidos no grupo que recebeu a operação aberta, enquanto 19 linfonodos foram removidos (IC 95%: 14-24) no grupo laparoscópico (p=0,021). Linfadenectomia adequada (remoção de, pelo menos, 12 nódulos linfáticos) foi obtida em 58,1% dos casos no total, em 50,0% dos pacientes que receberam a operação aberta, e em 75% dos que receberam a laparoscópica. Pacientes não idosos e aqueles com estágio avançado da doença eram mais propensos a receber linfadenectomia adequada (p=0,004 e p=0,035, respectivamente). CONCLUSÃO: O estágio da doença e a idade do paciente foram os fatores que tiveram a maior influência sobre a realização de linfadenectomia adequada. O tipo de procedimento cirúrgico não afetou o número de linfonodos removidos.

BACKGROUND: In the surgical treatment of colorectal cancer, a lymphadenectomy is considered adequate when at least 12 lymph nodes are removed. AIM: To evaluate whether videolaparoscopic surgery positively affects the rates of adequate lymphadenectomy. METHODS: An observational study was conducted with patients undergoing either open or videolaparoscopic surgery for colorectal cancer between 2008 and 2013. The following variables were collected: gender, age, tumor site, histology, degree of differentiation, tumor stage, number of lymph nodes removed, and number of lymph nodes affected by the disease. RESULTS: A total of 62 patients with colorectal cancer were included; 42 (67.7%) received open surgery, and 20 (32.3%) laparoscopic surgery. Regarding lymphadenectomy, a mean of 13 lymph nodes (95% CI: 10-16) were removed in the group that received open surgery, while 19 lymph nodes were removed (95% CI: 14-24) in the laparoscopic surgery group (p=0.021). Adequate lymphadenectomy (removal of at least 12 lymph nodes) was achieved in 58.1% of the total cases, in 50.0% of the patients who received open surgery, and in 75% of those who received laparoscopic surgery. Non-elderly patients and those with an advanced disease stage were more likely to receive an adequate lymphadenectomy (p=0.004 and p=0.035, respectively). CONCLUSION: Disease stage and patient age were the factors that had the greatest influence on achieving an adequate lymphadenectomy. The type of surgery did not affect the number of lymph nodes removed.

Barium monoferrite BaFe2O4 classified as permanent magnet stands out among other ceramic magnets due to its high chemical stability, corrosion resistance and low production cost. In addition, experiments conducted on photocatalytic degradation of methyl orange and UV transmittance by spectrophotometry have shown that this material has photocatalytic properties. The spinel ferrite is of importance in many technological areas such as computing, communications and security. Several techniques for synthesis have been studied to optimize the properties of this material. The synthesis of BaFe2O4 by conventional processes often occurs at temperatures above 1000 ºC. In this work, we obtained the phase BaFe2O4 at low temperatures (600 ºC) from the combustion reaction using nitrates and maleic anhydride as metal complexing agent. Techniques of X-ray diffraction, specific surface area, thermogravimetry analysis and photocatalytic analysis were employed to characterize the products obtained.

Os cimentos de fosfatos de cálcio são biomateriais formados pela mistura de um pó de fosfato de cálcio com água ou com solução aquosa de sais orgânicos ou inorgânicos formando uma pasta que reage à temperatura ambiente ou corpórea, endurecendo como resultado da reação de precipitação. Cimentos de fosfato de cálcio são usados comumente em cirurgias de preenchimento ósseo na odontologia e ortopedia, que requerem procedimentos extremamente invasivos. A inovação consiste em formular uma pasta injetável pela incorporação de aditivos. Neste estudo, três aditivos (carboxi-metil-celulose, polímero de agar e alginato de sódio) foram incorporados a fosfato tricálcico-alfa, nas concentrações de 0,4%; 0,8%; 1,6%; 3,2%; 6,4% em massa. Os resultados demonstraram que foi possível obter composições de cimento de fosfato tricálcico injetáveis. Verificou-se que a injetabilidade, medida por um método inédito proposto, depende do comportamento reológico das pastas. Neste estudo, as formulações com 1,6% de carboxi-metil-celulose, 1,6% de agar e 0,8% de alginato de sódio, permitiram a obtenção de uma viscosidade suficiente para uma boa homogeneização e injeção do cimento.

Calcium phosphate cements are biomaterials made of a mixture of calcium phosphate powder with water or with aqueous solutions of inorganic or organic salts, forming a paste that reacts at room or body temperature and hardens as a result of precipitation reactions. Calcium phosphate cements are commonly used in both dentistry and orthopedic bone filling surgeries, which require extremely invasive procedures. The innovation consists in formulate an injectable paste by incorporation of additives. In this work, three different additives (carboxymethylcellulose, agar polymer and calcium alginate) were incorporated in alpha-tricalcium phosphate (alpha-TCP), in concentrations of 0.4%; 0.8%; 1.6%; 3.2% and 6.4% wt%. Results showed that it was possible to obtain injectable compositions of tricalcium phosphate cement. It was verified that the injectability, measured by a novel method, depends on the rheological behavior of the pastes and injection time. In this study, pastes with sufficient viscosity for good homogenization and injection were obtained. In this study, pastes with 1.6% carboxymethylcellulose, 1.6% agar and 0.8% sodium alginate present sufficient viscosity for good homogenization for cement injection.

In this work, the feldspar used as a flux in typical porcelain was replaced by waste glass, and the resulting batch composition contained 50% kaolin, 25% quartz and 25% waste glass. The properties of this porcelain with glass powder (GP) were compared to traditional porcelain (TP), which utilizes feldspar. The samples were fired at different temperatures, ranging from 1200 °C to 1400 °C. Technical parameters, such as water absorption, modulus of rupture and K IC, phase analysis by XRD, and microstructure by SEM were analysed. The results indicated that the lower fracture toughness and MOR of GP is a consequence of the peculiar microstructure of this porcelain. The reduction in firing temperature and the use of a cheaper substitute for feldspar makes GP also an attractive economical alternative.