The electrical impedance diagnostic methods and instrumentation developed at the Gdansk and Warsaw Universities of Technology are described. On the basis of knowledge of their features, several original approaches to the broad field of electrical impedance applications are discussed. Analysis of electrical field distribution after external excitation, including electrode impedance, is of primary importance for measurement accuracy and determining the properties of the structures tested.

Firstly, the problem of electrical tissue properties is discussed. Particular cells are specified for in vitro and in vivo measurements and for impedance spectrometry. Of especial importance are the findings concerning the electrical properties of breast cancer, muscle anisotropy and the properties of heart tissue and flowing blood. The applications are both important and wide-ranging but, for the present, special attention has been focused on the evaluation of cardiosurgical interventions.

Secondly, methods of instrument construction are presented which use an electrical change in conductance, such as impedance pletysmography and cardiography, for the examination of total systemic blood flow. A new method for the study of right pulmonary artery blood flow is also introduced. The basic applications cover examination of the mechanical activity of the heart and evaluation of many haemodynamic parameters related to this. Understanding the features that occur during blood flow is of major importance for the proper interpretation of measurement data.

Thirdly, the development of electrical impedance tomography (EIT) is traced for the purposes of determining the internal structure of organs within the broad field of 2-D and 3-D analysis and including modelling of the organs being tested, the development of reconstruction algorithms and the construction of hardware.

In recent years, the technical and economic feasibility of using microalgae and cyanobacteria has been explored for the removal and exploitation of domestic, agricultural and industrial residual effluents with high C, N and P compounds content. To contribute to the understanding of the process and its technical viability for microalgae growth, the article discusses monitoring, flow determination, and physicochemical characteristics of two types of effluents generated in an experimental farm located in the east of Colombia, before (R1) and after biological treatment (R2). In general, the results showed the reduction of different parameters, such as total dissolved solids (TDS), hardness, salinity and phosphates after treatment with activated sludge. However, the conductivity value obtained in R1 and R2 showed the presence of a pollutant load. These findings can be attributed to the highest concentration of fats and oils in the water during early hours of the day. Finally, although the concentration of nitrates increased from 46.63 to 225.21 mg∙dm–3 and phosphate decreased slightly from 9.65 to 6.21 mg∙dm–3, no inhibition was generated in the microalgae, as evidenced in the growth of the microalgal biomass in effluents after nitrate and phosphate removal above 80%.

An innovative measurement setup for the dielectric characterisation of fibres in a terahertz time-domain spectrometer using an HDPE elliptical lens for coupling into the fibres has been built and validated by measurements of several different types of samples. The setup is based on a commercial all fibre-coupled terahertz time-domain spectrometer. Measurements of the effective refractive index have been conducted on polypropylene-based three-dimensional printing filaments, silica glass rods, and a polytetrafluoroethylene cord of lowered density, covering the frequency range of approximately 100 GHz to 1 THz. The theoretical part of the work includes numerical calculations performed via the finite difference eigenmode method and the characteristic equations of a uniform circular dielectric waveguide for a few guided modes, from which it is clear that primarily the fundamental mode propagates along the fibre. Details on model-based phase corrections, crucial to the accurate determination of the effective refractive index of dispersive fibres, have been presented as well.

In the present work, bacteria of the Pseudomonas genus native to the Ecuadorian Amazon with the capacity to treat contaminated water and soils were selected. For this purpose, 20 soil samples from Amazon region with evidence of contamination were analysed. For identification, each sample was assigned a code according to the sampling area: Joya de los Sachas (S), Minga (M) and Siete de Julio-Shushufindi (SH). The cultures were performed in the combination of Bushnell Hass (BH) + Luria Bertani (LB) and Müeller-Hinton (MH) + Brucella agar (BA) media, all with the addition of diesel to verify their efficacy in the growth of bacteria capable of surviving in contaminated media. The combination with ideal results was that of BH + LB, by means of Gram-staining it was determined that 19 of the samples had interest microorganisms. To characterize the isolates at the species level, biochemical tests of: catalase, citrate, glucose, hemolytic activity and urease were applied, which allowed to confirm the existence of the Pseudomonas of interest. The results indicated that P. stutzeri (in samples S1 and M1), P. aeruginosa (in SH2 and SH5) and P. putida (in S7, S8, S10 and SH4) obtaining a total of 8 isolates (40%) of interest from the initial 19. With the results obtained from this work, an optimal culture method was standardized for the selection of bacteria with potential for treating contaminated soils and water.

We report on the first application of the graphics processing units (GPUs) accelerated computing technology to improve performance of numerical methods used for the optical characterization of evaporating microdroplets. Single microdroplets of various liquids with different volatility and molecular weight (glycerine, glycols, water, etc.), as well as mixtures of liquids and diverse suspensions evaporate inside the electrodynamic trap under the chosen temperature and composition of atmosphere. The series of scattering patterns recorded from the evaporating microdroplets are processed by fitting complete Mie theory predictions with gradientless lookup table method. We showed that computations on GPUs can be effectively applied to inverse scattering problems. In particular, our technique accelerated calculations of the Mie scattering theory on a single-core processor in a Matlab environment over 800 times and almost 100 times comparing to the corresponding code in C language. Additionally, we overcame problems of the time-consuming data post-processing when some of the parameters (particularly the refractive index) of an investigated liquid are uncertain. Our program allows us to track the parameters characterizing the evaporating droplet nearly simultaneously with the progress of evaporation.