Study of mixtures using simplex design for the addition of chamotte in clay bricks

The red clay ceramic industry is associated with several environmental damages, from the extraction of natural resources as raw materials to the generation of high amounts of waste. This study proposed the incorporation of the ceramic bricks waste (chamotte) in ceramic mixtures for the production of clay bricks. In order to define the greater content of chamotte, which can be added maintaining the technical qualities required for the product, the experimental design of mixtures was used, with the production of bricks containing the chamotte and two other clayey materials. The compositions were subjected to firing at 850, 950, and 1050°C. The properties of firing linear shrinkage, apparent specific mass, water absorption, apparent porosity, and axial compressive strength were evaluated. It was observed that chamotte (C) contributed to the improvement of some of these properties, such as linear shrinkage. Overlapping the response surfaces obtained in the statistical analysis, the optimal chamotte (C) content was determined for each firing temperature. It was concluded that the incorporation of up to 30% chamotte (C) is technically feasible considering the evaluated temperature range. In this way, there is a product that adds both sustainability and technical performance to the ceramic industry.     

Oil Quality and Yield of Different Carthamus tinctorius Cultivars: Promising Oilseeds for Biodiesel in Semi-Arid Regions

In this study, seed productivity and oil content of three safflower genotypes (IMAMT 1750, IMAMT 946 and IMAMT 894) cultivated in the Brazilian semi-arid region were evaluated to identify which genotype has the best in-field performance. The acidity and saponification index were evaluated, as well as the efficiency of lipid extraction through thermal analysis, aiming to estimate the species' potential for biofuel production in semi-arid regions. Field cultivation under semi-arid conditions lasted for ~75 days and no herbivory were observed on the plants. The IMAMT 894 genotype presented higher seed yield than the other genotypes, IMAMT 1750 presented 34% oil, and IMAMT 946 and IMAMT 894 presented 32% oil with efficient extraction in the Soxhlet system and high oil content and quality; higher than traditionally used crops such as soybean and cotton. The IMAMT 894 genotype showed higher seed productivity, but all three genotypes presented good oil yield and quality for biodiesel production. Oil extraction in the Soxhlet system was efficient since the thermogravimetric analysis showed no oil in the residual biomass after oil extraction.     

The influence of organization of LbL films containing a silsesquioxane polymer on the electrochemical response of dopamine

This paper describes the construction, evaluation, and application of an electrochemical sensor for the determination of dopamine (DA) in the presence of ascorbic acid (AA) and uric acid (UA). Satisfactory results were achieved for the simultaneous determination of DA and UA, it was verified that it is possible to detect AA in the presence of DA, but high concentrations of AA interfere in detection of DA. The sensor was constructed using the layer-by-layer (LbL) technique with the modification of the surface of indium tin oxide coated glass (ITO) substrate with nanostructured films comprising a 3-n-propylpyridinium silsesquioxane polymer (SiPy⁺Cl^?) and nickel(II) tetrasulfophthalocyanine (NiTsPc). Using the square wave voltammetry technique (SWV), the LbL modified electrodes produced at different pHs (pH 2 and 8) were used to determine DA in the presence UA, and the electrochemical responses of the electrodes were compared. It was observed that the electrodes with the highest concentration of monomeric species showed the highest current intensity and the lowest peak potential for the DA and UA analytes in analysis of DA and UA, individually and simultaneously, with peak potential separation of 460 mV versus Ag/AgCl. Applying SWV, a linear dynamic range of 10–99 μmol L^?1 and 100–900 μmol L^?1 with detection limit of 16.8 μmol L^?1 and 58.3 μmol L^?1 was obtained for DA and UA, respectively. The method has good selectivity and sensitivity, and it was successfully applied to the simultaneous determination of DA and UA in spiked human urine sample.     

A computational model for the flow within rigid stator progressing cavity pumps

This work presents the development of a novel computational model for the 3D-transient flow in a Progressing Cavity Pump (PCP) that includes the relative motion between the rotor and stator. The governing equations are solved using an Element-based Finite Volume Method in a moving mesh. The model implementation is only possible due to the meticulous mesh generation and motion algorithm described herein, which is considered to be one of the main contributions of the present work. The model developed in this study is capable of precisely predicting volumetric efficiency and viscous loses in addition to providing detailed information about the pressure and velocity fields inside the device. Turbulence effects are accurately treated with advanced turbulence models. In addition, although the presented results are for single phase flow, the model can be extended to account for multiphase flows using models available in CFD software. In addition, some aspects related to inertial effects that are not captured by simplified models are analyzed using this model. The results presented herein consider a rigid stator pump. The model was validated against experimental results from literature.     

Quantitation of hepatitis G and C viruses in the liver: evidence that hepatitis G virus is not hepatotropic

Hepatitis G virus (HGV) is prevalent in patients with chronic liver disease and has been previously detected in liver specimens. However, it is unknown whether the virus is replicating in the liver or is simply a contaminant from serum. We sought to determine whether HGV was hepatotropic and to determine whether coinfection with HGV and hepatitis C virus (HCV) influenced the level of either virus. Virus was quantitated using branched DNA (bDNA) assay for both HGV and HCV in the liver explants and pretransplant serum samples from 30 transplant recipients: Group I, HGV/HCV coinfection (n = 10); group II, HCV infection alone, (n = 8); group III, HGV alone (n = 12). In patients with coinfection HCV (RNA) titers in liver were consistently higher than those for HGV RNA (median 1.13 x 10(8) and 360,000 Eq/g respectively, P < .01). The ratio of liver/serum viral RNA was significantly higher for HCV than for HGV (median 129 and 0.3 respectively, P < .01). Levels of HCV RNA were similar in patients with HCV infection alone versus those with HGV/HCV coinfection (median; liver = 1.15 x 10(7) vs. 1.13 x 10(8) Eq/g, serum = 500,000 vs. 200,000 Eq/mL) and levels of HGV RNA in liver and serum were similar in patients with HGV infection alone compared to those with HGV/HCV coinfection (median; liver = 1.2 x 10(6) vs. 4.0 x 10(5) Eq/g, serum = 4.5 x 106 vs. 2.6 x 10(6) Eq/mL). Levels of either virus appeared unaffected by the presence of an additional virus. The high ratio of HCV RNA levels in liver compared to serum is consistent with its known hepatotropism, but this pattern was not observed for HGV. The median liver/serum ratio of HGV RNA was less than unity, a finding consistent with serum contamination of liver tissue. Thus we conclude that the liver is not the main site of HGV replication.     

Calculation of vapor-liquid equilibria in aqueous sulfuric acid solutions using the UNIQUAC equation in the whole concentration range

Sulfuric acid has many industrial applications. Its main use can be related to fertilizer manufacture, process with ore, chemical synthesis, liquid effluents treatment and the petroleum refine. A main characteristic of this acid is its behavior depending on concentration. When it is dilute, under molar concentrations of 90%, the solution acts as a strong acid and does not show dehydration power. On the other hand, when it is concentrated, above 90%, its acidic feature is omitted and its dehydration power increases. Due to its importance in chemical process and in view of all works present in the literature, one does not consider both dissociation reactions in the liquid phase and the complex formation reaction in the vapor as one, a thermodynamic model has been developed using Prigogine and Defay Chemical Theory. This model takes into account phase and chemical equilibria, simultaneously, with satisfactory results to calculate vapor-liquid equilibria of H₂O-H₂SO₄ solutions in the whole concentration range and temperatures from 0 to 150 °C.     

Enzymatic Reactions in Near Critical CO2: The Effect of Pressure on Phenol Removal by Tyrosinase

The use of enzymes in supercritical CO₂ (SCCO₂) has received extensive attention in recent years. Biocatalysts have the advantage of substrate specificity and SCCO₂ offers several advantages over liquid solvents. This work deals with the utilization of SCCO₂ as a medium for the enzymatic removal of phenol from aqueous solutions using tyrosinase. Since the presence of oxygen is crucial for the enzyme-catalyzed oxidation, the substantial solvating power of SCCO₂ makes it a promising medium for such reactions. The conversion of phenol was higher at 10 MPa. Under near critical conditions (7 MPa, 35 °C), the addition of air at 5 × 10⁵ Pa of pressure improved phenol removal.     

Color vision discrimination in the capuchin monkey Cebus apella: evidence for trichromaticity

Primates display significant differences in color vision. The purpose of this study was to assess the ability of capuchin monkeys in discriminating chromatic and achromatic Munsell color chips through behavioral tests. The subjects were trained in a simple and reverse discrimination learning procedure. All subjects were capable of discriminations along five color categories investigated. The results are discussed in terms of the hypothesis of male dichromatism in New World monkeys, the role of color vision in adaptation to feeding ecology, as well as to aspects regarding primate evolution.     

A Reed-Solomon Based Method to Improve Message Delivery in Delay Tolerant Networks

Delay and Disruption Tolerant Networks are made up of mobile wireless nodes which may experience major message delivery restrictions. Such restrictions are the result of intermittent connectivity and scattered topology. Within these networks, messages can be detained for long periods of time or never be delivered. Existing solutions that purport improved message delivery rates modify routing protocols to perform integrity verification with each hop, resulting in routing overhead and, very often, unnecessary processing costs. This article proposes a scheme, named EMCOD, which decreases message delivery delay, while minimally increasing the processing overheads. To achieve this, EMCOD uses data encoding and interleaving to create messages. The original data is reassembled from some of the messages received, without the need to wait for all messages to be received. In scenarios subject to long delays and/or significant packet loss rates, it is possible to reduce original data recovery times by more than 50%. The processing overhead resulting from the encoding procedures is offset by the data recovery capabilities, which effectively decreases network overheads by more than 60%, in the same scenarios. EMCOD modifies the Bundle Layer, without interfering with the remaining layers, making it possible to route the messages through nodes that do not implement the proposed scheme.