The influence of pyrocatechol added in pre-oscillatory period on the dynamics of the Bray-Liebhafsky reaction

In the past two decades, chemical oscillators have emerged as a popular tool for the determination of “reactive” analytes due to their great sensitivity toward any kind of external perturbations. They have found application in many fields of applied science enabling relatively easy quantitative and qualitative analyses. In this study influence of pyrocatechol, an important precursor in many organic syntheses, on the pre-oscillatory period of the Bray-Liebhafsky (BL) reaction was examined. The BL reaction was followed by the potentiometric method. In a series of experiments (in a concentration range from 1.5 × 10-5 M to 3 × 10-5 M), pyrocatechol was added 45 minutes after the start of the reaction, causing an immediate appearance of oscillations. For these experimental conditions, the period between the first and second oscillation increases linearly with the added pyrocatechol concentration. The obtained results can be useful for analytical purposes and accordingly, potential determination of unknown pyrocatechol concentration

Bioinspired NEMS-Prospective of Collaboration with Nature

The fields of micro- and nanomechanics are strongly interconnected with the development of micro-electro-mechanical (MEMS) and nano-electro-mechanical (NEMS) devices, their fabrication and applications. This article highlights the biomimetic concept of designing new nanodevices for advanced materials and sensing applications

Temperature pattern measurements in Briggs-Rauscher oscillaotry reaction with state I to state II transition

Thermal monitoring of a Briggs-Rauscher oscillatory reaction with a phase transition or the state I (low concentration of iodide and iodine) to the state II (high concentration of iodide and iodine) transition with formation of new solid iodine phase is presented. This is the very first time that an oscillatory reaction and the state I to state II transition have been monitored using a thermal camera. It should be pointed out, that the BR reaction solution is not homogenized by stirring, and that only oxygen production influence the solution mixing. Therefore, the analysis was done at three sampling points on the cuvette where temperature change over time was observed, and compared with average temperature distribution. The first point is chosen to correspond to the top of the solution in the cuvette, followed by one in the middle of the volume and one at the very bottom of the cuvette. Although the state I to the state II transition itself is not reproducible (investigated transition exhibits crazy clock behavior), the overall temperature pattern has shown a reproducible character

The comparison of two methods used to observe a nonlinear system: potentiometry and holography

The transition from state I ( characterized by low iodide and iodine concentration) to state II (high iodide and iodine concentration) occurs in a nonlinear Briggs-Rauscher (BR) oscillatory reaction. This transition was studied by two methods: potentiometric and holographic. The first derivative technique was applied to the obtained electrochemical and holographic curves of the transition state I→state II to obtain the corresponding slopes. Based on these slopes, the results of the two methods are compared. The obtained holographic slope for the transition from state I to state II is higher than the potentiometric one in all selected reaction sections. In the initial phase of the transition from state I to state II, it is clear that the velocity of the holographic method is twice that of the potentiometric method. While this trend shows a twofold increase at the beginning of the phase transition, it deviates in the other phases, where the holographic measurements show a 1.5-fold higher rate in the middle. The obtained results could have a strong impact on the study of nonlinear systems in the future

The synthesis, characterization, behavior in the Briggs-Rauscher reaction, and photoluminescence properties of newly created phosphate-tungsten bronzed doped with cerium and praseodymium

Phosphate tungsten bronzes (PWBs), due to their intriguing and potentially valuable properties, have consistently garnered research attention [1]. In this study, we introduced two rare-earth metallic elements, namely cerium and praseodymium, as dopants for PWBs. This led to the successful synthesis of novel PWBs doped with cerium and praseodymium, which were subsequently subjected to various characterization techniques, including thermal analyses (TA), Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD), scanning electron microscopy with energy-dispersive X-ray spectrometry (SEM-EDX), and hotoluminescence spectroscopy (PL). The behavior of cerium and praseodymium doped phosphate tungsten bronzes (Ce-PWB and Pr-PWB) [2], was investigated in the Briggs-Rauscher (BR) oscillatory reaction. The alterations in the oscillatory dynamics, brought about by the incorporation of cerium and praseodymium dopants, served as a means to distinguish between these bronzes. Additionally, this approach provided a method for assessing the catalytic properties of the bronzes. Apart from their nonlinear behavior, these bronzes also exhibited photoluminescence in the visible spectrum, specifically in the blue region

Effect of CoMoO4 nanopowders synthesized by glycine nitrate procedure and calcinated at 450 °C on Briggs-Rauscher oscillatory dynamics

Cobalt molybdate is of importantce for the development of mobile telecommunication systems, such as mobile phones and high-quality microwave dielectric ceramics for high resonant frequency selectivity in microwave devices. Due to their special catalytic properties, cobalt molybdates have been used as catalysts in many chemical and petrochemical processes. The CoMoO4 nanoparticles ware synthetized in a simple, quick, and inexpensive way, by using a glycine nitrate procedure (GNP), with and without calcination at 450 °C [1], and investigated by applying the Briggs-Rauscher oscillatory reaction method [2]. The complex oscillatory BR reaction is sensitive to different insoluble analyte addition [3]. This feature of BR oscillatory reaction is used to investigate effect of different masses of GNP synthetized (with and without calcination at 450 °C) CoMoO4 samples on oscillatory dynamics. These two samples give the complete different effects in BR reaction. Obtained results strongly suggest that BR oscillatory reaction could be used for distinguishing these two samples, opening new direction in the investigation of ceramics materials

Effect of CoMoO4 nanopowders synthesized by glycine nitrate procedure and calcinated at 450 °C on Briggs-Rauscher oscillatory dynamics

Cobalt molybdate is of importantce for the development of mobile telecommunication systems, such as mobile phones and high-quality microwave dielectric ceramics for high resonant frequency selectivity in microwave devices. Due to their special catalytic properties, cobalt molybdates have been used as catalysts in many chemical and petrochemical processes. The CoMoO4 nanoparticles ware synthetized in a simple, quick, and inexpensive way, by using a glycine nitrate procedure (GNP), with and without calcination at 450 °C [1], and investigated by applying the Briggs-Rauscher oscillatory reaction method [2]. The complex oscillatory BR reaction is sensitive to different insoluble analyte addition [3]. This feature of BR oscillatory reaction is used to investigate effect of different masses of GNP synthetized (with and without calcination at 450 °C) CoMoO4 samples on oscillatory dynamics. These two samples give the complete different effects in BR reaction. Obtained results strongly suggest that BR oscillatory reaction could be used for distinguishing these two samples, opening new direction in the investigation of ceramics materials

Comparison of the luminescence properties of phosphate-tungsten bronze and cerium doped phosphate-tungsten bronze

Phosphate-tungsten bronzes (PWBs) constantly attract a lot of attention owing to their interesting chemical, mechanical, and optical properties. Furthermore, tungsten bronzes as inert inorganic solids, exhibit interesting and useful electronic properties when rare-earth ions are incorporated into their structure. Cerium doped phosphate-tungsten bronze (Ce-PWB) is obtained in the process of phase transformations of CePW12O40×6H2O (Ce-PWA) salt. The brown crystals of Ce-PWB are formed after heating of Ce-PWA in a furnace, in a temperature range from room temperature to 650 °C. In the present paper the luminescence properties of undoped PWB and Ce-PWB are analyzed and compared. Regarding the characterized luminescence properties of PWB and Ce-PWB, only PWB matrix showed luminescence, while dopant Ce3+ had no significant influence on the change of the emission spectra with characteristic spectra for this ion. The obtained CIE chromaticity diagrams showed that both samples emit in the deep blue region, suggesting their possible use as a blue emitting source for white light-emitting diodes (LEDs)

Holography method as a powerful tool for the investigation of chemical reactions: experimental setup

Holography, i.e. holographic interferometry, is a method that records the deformation, i.e. the dynamics of the process between two or more moments of exposure. The presented work defined the holographic method with an appropriate experimental setup. The experimental setup consists of optical components specially designed for measuring chemical reactions. This setup is specific because it has the possibility of so-called triple recording. The possibility of observing the process without disturbing it is of great importance for the investigation of very sensitive chemical reactions, such as oscillatory reactions. This kind of experimental setup opens up possibilities for exploring the profiles of various chemical reactions on the nanoscale; especially iodate-based oscillatory reactions for which the exact mechanism is still unknown

Corrugation elasticity as a new property of nanostructured material: holographic analysis of apatura butterfly wings

The corrugation of the structure is a special property of the material that has a great influence on almost all other characteristics of the same. The connection between materials based on the corrugation of natural structures such as Apatura butterfly wings and its examination (the six samples of same species) by the method of holographic interferometry (with four different wavelengths of laser radiation) is presented in this paper. The concept of material's corrugation elasticity is presented as well as the advantages of this concept. The holographic method was implemented as appropriate for monitoring the structure dynamics at the nanoscale. Finally, the important factor that impacts the elasticity of the corrugation of the material lies in the optical factors of the environment is emphasized, i.e., in the light of laser radiation that structure interferes with. A completely non-linear dependence on the wavelengths of light is shown, where for wavelengths of 532 nm and 660 nm the elasticity of the corrugation is observed, while for 450 nm and 980 nm a plastic deformation of the corrugation is observed. These preliminary studies open new possibilities in the synthesis and testing of different materials and monitoring of their dynamics in real time