The characterization of ultra-soft soil behavior is one of the most difficult challenges since the water content in such soils is very high. Hence, nondestructive or special measurement is required. Therefore, the behavior of untreated and treated ultra-soft soil was characterized using both miniature penetrometer and electrical methods. The ultra-soft soil was prepared with 2% to 10% bentonite. The soil with 10% bentonite was treated with 2% to 10% lime and with 1% to 10% polymer separately. The pH, CIGMAT miniature penetrometer, and electrical resistivity combined with the measured shear strength from the modified vane shear device were used to characterize the ultra-soft soils. The CIGMAT miniature penetrometer penetration varied linearly with the shear strength of the untreated and treated soft soils with 10% bentonite. Relative electrical resistivity decreased by 246% when the bentonite content was increased from 2% to 10% in the ultra-soft soil. The addition of 10% of the lime to the ultra-soft soil with 10% of bentonite content decreased the relative electrical resistivity by 171%. The addition of 10% of the polymer to the ultra-soft soil with 10% of bentonite content reduced the relative electrical resistivity by 545%. Power law, linear and hyperbolic models were used to predict the shear strength- electrical resistivity relationship for the untreated, lime-treated and polymer-treated ultra-soft soils respectively. The CIGMAT miniature penetrometer was modeled using 3-D axisymmetric finite element method, which predicted the penetration of CIGMAT penetrometer that agreed well with the experimental results of the ultra-soft soils.
Polymer materials exhibit a high ductility. Determination of the yield strain as well as the break (ultimate) strain is usually done on the basis of tensile tests performed on standard samples and evaluated for normalizhed measured length, supposing the homogeneous material deformation along the sample axis. This experimental approach does not take into account the plastic strain concentration ii small neck area during the final deformation phase before the sample rupture, what is typical for the plastics behavior. Application of so defined material characteristic in the case of Finite element metod (FEM) analyses of real constructions made of TSCP plastics (typical semi-crystal polymer) led to significantly conservative (smaller) values of ultimate loads compared to the measured ones. A special experimental method making use of high-speed camera has been developed to determine the strain in defined small area of local strain concentration being also in correlation with the FEM element size. Application of the more realistic (higher local) break strain value in the case of FEM analyses of real TSCP constructions led to much better agreement between the calculated and measured stiffness and ultimate load values.
Organic electronics represents a revolutionary, new way of electronics, which is based on the combination of a new class of materials and large area, high volume deposition and patterning techniques. Often also terms like printed, plastic, polymer or flexible electronics are used, which essentially all mean a progressive way of electronic manufacturing beyond the classical approach. Till today, it has been demonstrated many electronic devices based on organic materials, for instance organic photovoltaic cells, memory devices, printed RFIDs, batteries, sensors or OLED displays. Activities in the field of organic electronics conducted at the Department of Technologies and Measurements are focused mainly on sensor applications and construction of organic field-effect transistors. and Organická elektronika představuje nové a v mnoha ohledech revoluční odvětví, které je postaveno na unikátních vlastnostech určitých organických materiálů. Z hlediska elektroniky jsou velmi zajímavé zejména elektrické vlastnosti těchto materiálů. V tomto odvětví se můžeme setkat s pojmy jako tištěná elektronika, flexibilní elektronika, popřípadě polymerní elektronika. V současnosti jsou organické materiály využívané v organických fotovoltaických článcích, paměťových obvodech, bateriích, tištěných RFID, senzorech popřípadě v OLED displejích. Výzkum v oblasti organických materiálů se na katedře technologií a měření soustředí zejména na využití těchto materiálů pro senzorové aplikace a pro konstrukci organických tranzistorů řízených elektrickým polem.