Runtime verification of autopilot systems using a fragment of MTL- $${\int }$$

International Journal on Software Tools for Technology Transfer - Current real-time embedded systems development frameworks lack support for the verification of properties using explicit time where...     

Stability of microencapsulated lactic acid bacteria under acidic and bile juice conditions

The probiotic strains Lactobacillus brevis CCMA1284 and Lactobacillus plantarum CCMA0359 were microencapsulated by spray drying using different matrices – whey powder (W), whey powder with inulin (WI) and whey powder with maltodextrin (WM). Viability of the microencapsulated strains in acid and bile juices and during 90 days of storage (seven and 25 °C) was evaluated. The two strains exhibited high encapsulation efficiency (> 86%) by spray drying. The different matrices maintained L. plantarum viability above six log CFU g⁻¹ at 7 °C for 90 days, whereas similar results for L. brevis were observed only for W. The use of inulin as matrix of encapsulation did not enhance bacterial viability in the evaluated conditions. In general, the use of W and WM as matrices was effective for L. plantarum viability. However, only W was effective for L. brevis in the evaluated conditions. The spray drying technique was successfully adopted for the encapsulation of L. plantarum CCMA0359 and L. brevis CCMA1284 strains.     

Prediction models for multiphase-flow-induced corrosion of API X80 steel in CO2/H2S environment

In the offshore oil and gas industry, mainly focusing on the use of rigid or flexible pipes of subsea infrastructure applied to risers or flowlines, one of the greatest difficulties is the interpretation of the combined effects of the various correlated phenomena (hydrodynamic effects of intermittent flow, the effects of corrosivity of the environment in addition to variations in pressure, temperature, and dynamic loading). On the basis of this scenario, defining the degree of severity of each of the correlated system variables becomes of fundamental importance for establishing reliable criteria for selecting materials for subsea application. The established flow pattern directly affects the corrosion rate (or the pipe material mass loss), but the balance of other variables including possible changes in the physical and transported fluid chemical properties may increase the damage up to an order of magnitude, which is a piece of information normally not foreseen in design criteria. Therefore, to improve the understanding of the corrosion study influenced by multiphase flow, a testing loop was designed and assembled at the Corrosion and Protection Laboratory of the Institute for Technological Research, in which API X80 steel coupons were positioned in locations with a 0° and 45° inclinations. Tests were conducted by varying the partial pressure of the gaseous phase containing blends of CO₂ and H₂S with N₂ balance, mixed with the liquid phase containing light oil and heavy oil in water with salinity (NaCl)-simulating oil well conditions with 80% water cut. The main objective of this study is to establish models that can predict the corrosion intensity in conditions close to those obtained experimentally. To achieve results, the multiple regression and Box–Cox transformation methods were applied. These models will make possible damage prediction and optimization of matrix parameters for the multiphase-loop test.     

Silica nanoparticles functionalized with a thermochromic dye for textile applications

The aim of this work was the fabrication of mesoporous silica nanoparticles functionalized with thermochromic dye for further incorporation onto textiles. The nanosilicas were prepared under alkaline conditions in the presence of the surfactant hexadecyltrimethylammonium chloride and functionalized with the organosilane dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (C18-NTMS). The dye was incorporated onto the mesoporous silica nanoparticles by two different methods: co-condensation and post-grafting, i.e. by adding the dye during or after the synthesis of the nanosilica, respectively. The morphology, particle and pore size, chemical composition, and textural properties of the silica nanoparticles were characterized by scanning electron microscopy (SEM), dynamic light scattering, N₂ adsorption isotherms at ?196 °C, Fourier transform infrared spectroscopy and thermogravimetry. The silica nanoparticles prepared with and without dye presented spherical shape (by SEM) and particle size ranging from 15 to 40 nm. The infrared spectra revealed the characteristic bands of silica and organosilane (in the cases where it was used). The prepared materials presented colour change when submitted to different conditions. The thermochromic dye-functionalized nanosilicas were efficiently immobilized into cotton fabric and tests were performed to verify the washing fastness. After washing, a slight decrease on the amount of silica was noticed, but much of it remained on the textile. The functionalized textiles presented a colour change within different conditions.     

Biochemical characterisation and application of lipases produced by Aspergillus sp. on solid‐state fermentation using three substrates

Lipase from Aspergillus sp. obtained by solid‐state fermentation (SSF) on wheat bran (LWB), soybean bran (LSB) and soybean bran combined with sugarcane bagasse (LSBBC) were 67.5, 58 and 57.3 U of crude lipase per gram substrate, respectively. The optimum pH of activity and stability of the LWB was between 8 and 9, and the optimum temperature of activity and stability was 50 °C and up to 60 °C, respectively. The LSB and LSBBC showed two peaks of optimum pH (4 and 6) and optimal values of temperature and stability at 50 °C. The LSB was stable in the pH range of 6–7, while LSBBC in the range of pH 4–7. All the enzymes show activities on p‐nitrophenyl esters (butyrate, laurate and palmitate). LWB stood out either on the hydrolysis of sunflower oil, presenting 66.1% of the activity over commercial lipase and on the esterification of oleic acid and ethanol, surpassing the activities of the commercial lipases studied. The thin layer chromatography showed that LWB and LSB have produced ethyl esters from corn oil, while LWB produced it from sunflower oil.     

Dissolving grade eco-clean cellulose pulps by integrated fractionation of cardoon (Cynara cardunculus L.) stalk biomass

A biorefinery scheme with separate processing of the two main carbohydrate streams (cellulose and hemicellulose-derived) was employed to the energy crop cardoon (Cynara cardunculus L.) to fractionate the whole stalk material. A high quality xylose-enriched substrate was obtained after selective one-step dilute sulfuric acid hydrolysis of hemicelluloses, yielding 18.1 g of xylose per 100 g of dry biomass. The xylan-free solid residue was delignified by sulfur-free organosolv pulping to produce dissolving grade pulps having 93.8% of α-cellulose (33.1 g per 100 g dry initial biomass) and 79.5% degree of crystallinity. About 76% of crop lignin (13.8 g per 100 g dry initial biomass) was recovered from the spent pulping liquor as a high purity reactive precipitated organosolv lignin. Response surface methodology was used for statistical modeling and optimization of the applied separation processes. The central composite rotatable design was applied to assess the effects of the principal technological parameters on the main reaction outputs.     

Real time algorithms for digital pulse processing applied to gamma-ray and hard X-ray spectroscopy

The duration of a single plasma discharge in the next generation of fusion experiments will be much longer than in the present devices. Storing all raw data acquired in each discharge will be more difficult and the high rates achieved by the new digitizers are already contributing to storage overload. This gap can be mitigated by real time (RT) analysis and compression, using devices such as field programmable gate arrays (FPGAs) capable to transfer and process data on the fly. However, to ensure a correct RT analysis, the FPGA algorithm must be adapted to the signal to be acquired. Since minor changes in signal shape may require significant algorithm modifications, it is important to know in advance the signal attributes. For that reason, the availability of more than one RT algorithm, especially during commissioning of new sub-systems and during campaigns with relevant changes in diagnostic conditions, is advantageous. This paper presents an implementation using two RT algorithms processing simultaneously, developed for the gamma-ray and hard X-ray diagnostics of the Joint European Torus (JET). Both algorithms perform pulse height analysis with pile-up rejection. While the first algorithm is suitable for Gaussian shaped pulses, the second is suitable for exponential signals. The algorithms are selectable by the user, during discharge configuration. Tests with radioactive sources made in JET are presented.     

High surface area LaNiO<Subscript>3</Subscript> electrodes for oxygen electrocatalysis in alkaline media

LaNiO₃ coatings on nickel-foam supports were prepared by brush painting. The electrochemical properties were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Comparative studies were performed with LaNiO₃-pelleted electrodes. The roughness factors were determined by CV and found to be 5,208 ± 350 and 4,037 ± 250 for the pelleted and coated electrodes, respectively. EIS measurements confirm the results obtained by CV. Values lower than 0.3 were calculated for the morphology factors for both electrodes, indicating low electrochemical porosity. The experimental method used in this work to synthesise the oxide coupled with the use of Ni foam as support has proved to be very effective in producing oxide electrodes with surface areas higher than those referred to in relevant literature.     

Optimization of Lithium Extraction from Lepidolite by Roasting Using Sodium and Calcium Sulfates

The lithium extraction from a lepidolite concentrate using roasting, followed by water leaching, was studied. Several alternative additives were initially tested. The use of sodium and calcium sulfates as additives was evaluated in more detail. The influence of some process variables, namely the roasting time, roasting temperature and the additive/concentrate mass ratio, was studied applying a design of experiments. The lithium extraction was modelled and the fitted and validated model was used to optimize the process response. The increase in the additive/concentrate mass ratio, roasting time and temperature seems to result in solid state reactions and transformations that lead to phase, morphological and particle size distribution modifications, which were assessed by XRPD, SEM, and particle size analyses. In this process, lithium sodium sulfate formation constitutes a crucial step enabling the Li water leaching. High lithium extractions were estimated for several combinations of factors. At 850°C, lithium extractions over 90% are obtained when the roasting time is above 1.90 hour and the additive/concentrate mass ratios are over 0.77. An increase in the temperature to 875°C also leads to lithium extractions over 90% for a roasting time of 1 hour and an additive/concentrate mass ratio of 0.60.