Tallinn University of Technology

About: Tallinn University of Technology is a education organization based out in Tallinn, Estonia. It is known for research contribution in the topics: European union & Oil shale. The organization has 3688 authors who have published 10313 publications receiving 145058 citations. The organization is also known as: Tallinn Technical University & Tallinna Tehnikaülikool.

Recent developments and challenges of aqueous mineral carbonation: a review

Abstract: Aqueous mineral carbonation is the most selected ‘ex-situ’ mineral carbonation route under research scrutiny and is among the earliest routes studied on a pilot scale. This review summarises the recent advancements in aqueous mineral carbonation and discusses the current frontiers, research gaps, and future perspectives of the process. It also provides useful insights into the current practices and conveys the required actions to overcome the present challenges in the field. The key factors hindering the successful deployment of the technology on a large scale are the high cost of operation, energy intensity, slow reaction, and low carbon dioxide fixation efficiency ratio. Once the current challenges are circumvented, this aqueous route can stand as a potentially viable carbon sequestration technology for application in small-to-medium scale carbon dioxide emitters. The exponential increase in the number of studies and noticeable pilot-scale initiatives in recent years indicate that the aqueous mineral carbonation research is progressing in the right direction towards developing the technology as a promising, economically viable, and sustainable industrial carbon dioxide sequestration method.

Toxicity of nine (doped) rare earth metal oxides and respective individual metals to aquatic microorganisms Vibrio fischeri and Tetrahymena thermophila

Abstract: Despite the increasing use of rare earth elements (REEs) and oxides (REOs) in various technologies, the information on their ecotoxicological hazard is scarce. Here, the effects of La3+, Ce3+, Pr3+, Nd3+, Gd3+, CeO2, and eight doped REOs to marine bacteria Vibrio fischeri and freshwater protozoa Tetrahymena thermophila were studied in parallel with REO dopant metals (Co2+, Fe3+, Mn2+, Ni2+, Sr2+). The highest concentrations of REOs tested were 100 mg/L with protozoa in deionized water and 500 mg/L with bacteria in 2% NaCl. Although (i) most REOs produced reactive oxygen species; (ii) all studied soluble REEs were toxic to bacteria (half-effective concentration, EC50 3.5–21 mg metal/L; minimal bactericidal concentration, MBC 6.3–63 mg/L) and to protozoa (EC50 28–42 mg/L); and (iii) also some dopant metals (Ni2+, Fe3+) proved toxic (EC50 ≤ 3 mg/L), no toxicity of REOs to protozoa (EC50 > 100 mg/L) and bacteria (EC50 > 500 mg/L; MBC > 500 mg/L) was observed except for La2NiO4 (MBC 25 mg/L). According to kinetics of V. fischeri bioluminescence, the toxicity of REEs was triggered by disturbing cellular membrane integrity. Fortunately, as REEs and REOs are currently produced in moderate amounts and form in the environment insoluble salts and/or oxides, they apparently present no harm to aquatic bacteria and protozoa.

On mathematical modelling of solitary pulses in cylindrical biomembranes.

Abstract: The propagation of action potentials in nerve fibres is usually described by models based on the ionic hypotheses. However, this hypothesis does not provide explanation of other experimentally verified phenomena like the swelling of fibres and heat production during the nerve pulse propagation. Heimburg and Jackson (Proc Natl Acad Sci USA 102(28):9790–9795, 2005, Biophys Rev Lett 2:57–78, 2007) have proposed a model describing the swelling of fibres like a mechanical wave related to changes of longitudinal compressibility of the cylindrical membrane. In this paper, the possible dispersive effects in such microstructured cylinders are analysed from the viewpoint of solid mechanics, particularly using the information from the analysis of the well-known rod models. A more general governing equation is proposed which satisfies the conditions imposed by the physics of wave processes. The numerical simulations demonstrate the influence of nonlinearities, the role of various dispersion terms and the formation and propagation of solitary waves along the wall together with the corresponding transverse displacement. It is conjectured that due to the coupling effects between longitudinal and transverse displacements of a cylinder, the transverse displacement (i.e. swelling) is related to the derivative of the longitudinal displacement. In this way, the correspondence between theoretical and experimental (Tasaki in Physiol Chem Phys Med NMR 20:251–268, 1988) results can be described.