Sequential injection method for bi-parametric determination of iron and manganese in soil leachates

Sequential injection method for bi-parametric determination of Fe and Mn in soil leachates to assess the impact of micronutrients supplementation.

Automatic control of the sand granulation process to improve homogeneity in the manufacture of ceramic tiles

The purpose of this article is to quantify to what extent the design of an automatic control system for the clay sand granulation process will improve the percentage of homogeneity in the manufacture of ceramic tiles, through the analysis of the percentage of dust moisture. For which the process under study is initially described, identifying its stages, the control strategy to be used and its main characteristics. After conducting the research, it was determined that from the proposed control strategy, in which the flow of clay sand is controlled through frequency variators and the sequential injection of water spray through electric nozzles, it was achieved improve the homogeneity percentage by 94.78%, achieving that the error between the desired value and the present value of the humidity percentage is 0.015%, the approximation to the desired value or setpoint value being significant. Thus, it was also possible to determine that through an analysis of the dispersion model, that the collected data respond to a constant; evidencing that there is no sudden variation in the percentage of homogeneity during the automated operation of the process, which validates the improvement of homogeneity in the manufacture of ceramic tiles.

Sequential Injection System for Analysis of Degree Brix, Orthophosphate and pH in Raw Sugarcane Juice Applicable to Sugar Industry

This work presents, for the first time, a new sequential injection analysis (SIA) method to simultaneously analyze degree Brix, orthophosphate and pH in raw cane juice. These key parameters relate to price of harvested sugarcane and quality of cane juice for sugar production. The SIA system employed two detectors: the first detector is a diode-array spectrophotometer, equipped with a regular flow cell, for measurements of degree Brix and orthophosphate. Quantitative of degree Brix (°Bx; ca. % (w/w) sucrose) was based on manipulation of the schlieren effect at the interface between plugs of sample and water. Orthophosphate analysis was carried out based on the molybdenum blue method with significant reduction in consumption of the reagents. Compensation of the schlieren effect from sucrose for determination of orthophosphate was achieved by using a dual-wavelength spectrometric detection. Second detector is a pH-sensing device, called ion-selective field-effect transistors (ISFET). The ISFET is based on the current through the ISFET arising according to the H+ concentration in solution. Our developed SIA system provides linear calibration graphs fitting for purpose in analysis of sugarcane juice (pH: 0–14, °Bx: 1.0–7.0 and P2O5: 20–200 mg L−1). Simultaneous analysis of sugarcane juice for pH, °Bx and P2O5 is carried out within 5 min (12 sample per h). Precision of SIA system is acceptable (RSD < 3%). Our SIA system gave quantitative results insignificantly different, as compared with conventional methods for analysis of pH, °Bx and P2O5 in sugarcane juice.

Sequential Injection Analysis for Automation and Evaluation of Drug Liberation Profiles: Clotrimazole Liberation Monitoring

A fully automated sequential injection system was tested in terms of its application in liberation testing, and capabilities and limitations were discussed for clotrimazole liberation from three semisolid formulations. An evaluation based on kinetic profiles obtained in short and longer sampling intervals and steady-state flux values were applied as traditional methods. The obtained clotrimazole liberation profile was faster in the case of Delcore and slower for Clotrimazol AL and Canesten cream commercial formulations. The steady-state flux values for the tested formulations were 52 µg cm−2 h−1 for Canesten, 35 µg cm−2 h−1 for Clotrimazol AL, and 7.2 µg cm−2 h−1 for Delcore measured in 4 min sampling intervals. A simplified approach for the evaluation of the initial rate based on the gradient between the second and third sampling points was used for the first time and was found to correspond well with the results of the conventional methods. A comparison based on the ratio of the steady-state flux and the initial rate values for Canesten and Clotrimazol AL proved the similarity of the obtained results. The proposed alternative was successfully implemented for the comparison of short-term kinetic profiles. Consequently, a faster and simpler approach for dissolution/liberation testing can be used.

LAB-SCALE TESTS OF INCOHERENT ROCK REINFORCEMENT USING TWO-COMPONENT POLYMER BLENDS

The study addresses improvement of physical and mechanical properties of incoherent sediments by means of their chemical reinforcement using two-component resins. The lab-scale testing data on reinforcement of fine-grained quartz sand using two-component activated mineral and polyurethane resin blends are presented. Resins were injected by two ways on the tests. The first method was sequential injection of the polymer blend components in rock samples. The second method was injection of finished polymer blends. The two-component activated mineral and polyurethane resin blends ensure more effective reinforcement of incoherent sediment rocks as against foamed polyurethane blends. The uniaxial compression strength of reinforced fine-grained sand is 2.5-3 times higher in case of sequential injection of the components than in injection of finished mixtures. The elasticity modulus of the reinforced samples is 5.5-6 times higher in sequential injection than in injection of finished blends. The test results are useful for selection and optimization of injection method for two-component polymer blends in stabilization of broken rocks and in water-proofing of underground excavations.