Atomic Force Microscopy and Optical Studies of Organic Thin Films with Hydrogen-Bonded Networks

Brewster angle microscopy and atomic force microscopy were used to characterize the surface morphology of thin films in situ or after transfer onto solid supports. Two acids were studied, differing in carboxylic acid head groups, resulting in significantly different morphological features for thin films formed from these two amphiphiles on a Langmuir trough. Differences in self-assembly and domain sizes were correlated with the formation of hydrogen-bonded networks. The influence of surface hydrophobicity or hydrophilicity during deposition on morphology was also characterized, with spherulitic features appearing in some samples

Використання спеціалізованого програмного забезпечення для моделювання розливу рідких радіоактивних речовин у навчанні студентів і аспірантів

The study proves relevance of specialized software use to solve problems of emergencies prevention of radioactive liquids spills to teach students and graduate students. Main assessment criteria of accidents at radiation-hazardous objects associated with radioactive liquids spillage is identified. A model of radioactive substances transport in emergency rooms is developed. It takes into account physical features of radioactive liquid spill from the source, air pollution during transition of radioactive liquid from the spill surface into the air and subsequent scattering in the emergency room under influence of local air flows. It is determined that the existing software tools for radiation exposure assessment do not comprehensively cover features of such events and possess number of shortcomings regarding accidents modeling with spillage of radioactive liquids indoors. Computer modeling and forecasting examples for hypothetical event related to liquid radioactive spill in the JRODOS system are presented. The training process of future specialists, specialties 183 “Environmental Protection Technologies”, 143 “Nuclear Energy”, 103 “Earth Sciences”, and 122 “Computer Science” should be based on application of powerful scientific and methodological training base using modern achievements in the field of digital technologies. It is advisable to supplement curricula for students‘ and postgraduate students’ preparation in the mentioned above specialties by studying issues related to: development of mathematical models and software for solving problems of emergencies prevention in case of radioactive liquids spills; usage of features of specialized decision software of emergencies prevention during spills of radioactive liquids.У статті досліджено особливості використання спеціалізованого програмного забезпечення вирішення задач попередження надзвичайних ситуацій при розливах радіоактивних рідин у навчанні студентів і аспірантів. Визначено основні критерії для оцінювання аварій на радіаційно-небезпечних об’єктах пов’язаних з розливом радіоактивних рідин. Розроблена модель транспорту радіоактивних речовин у аварійних приміщеннях, що враховує фізичні особливостей витікання радіоактивної рідини з джерела, забруднення повітря при переході радіоактивної рідини з поверхні розливу в повітряне середовище та подальше їх розсіювання в аварійному приміщенні під впливом локальних повітряних потоків (спричинених, наприклад, вентиляцією). Визначено, що існуючі програмні засоби оцінки радіаційного впливу комплексно не охоплюють особливостей таких подій та мають ряд недоліків стосовно моделювання протікання аварій із розливом радіоактивних рідин в закритих приміщеннях. Представлено приклади комп’ютерного моделювання та прогнозування для гіпотетичної події, пов'язаної з розливом рідких радіоактивних середовищ в системі JRODOS. Процес підготовки майбутніх фахівців зі спеціальностей 183 «Технології захисту навколишнього середовища», 143 «Атомна енергетика», 103 «Науки про Землю», 122 «Комп’ютерні науки» має ґрунтуватись на використанні потужної науково-методологічної навчальної бази із використанням сучасних досягнень у сфері цифрових технологій. Доцільним є доповнення навчальних планів з підготовки студентів і аспірантів з окреслених спеціальностей вивченням питань щодо: розробки математичних моделей та програмних засобів вирішення задач попередження надзвичайних ситуацій при розливах радіоактивних рідин; особливостей використання спеціалізованого програмного забезпечення вирішення задач попередження надзвичайних ситуацій при розливах радіоактивних рідин

Efficient Retention and Alpha Spectroscopy of Actinides from Aqueous Solutions Using a Combination of Water-Soluble Star-like Polymers and Ultrafiltration Membranes

We explored two approaches to recover uranium and plutonium from aqueous solutions at pH 4 and pH 7 using water-soluble star-like polyacrylamide polymers with a dextran core. In the first approach, a solution comprising a neutral or ionomer polymer was mixed with a radionuclide solution to form polymer–metal complexes that were then retained by ultrafiltration (UF) membranes under applied pressure. The same polymers were first deposited on the membrane in the second approach using pressure-driven flow. The applied polymers had an overall diameter of gyration of 120 nm, which exceeded the nominal diameter of the UF membrane pores. The polymers showed a high affinity to uranyl but could also be used to extract Pu from neutral or near-neutral pH solutions. Direct-flow single-step filtration and alpha spectrometry demonstrated that the UF membranes containing star-like copolymers could recover 99% of U and up to 60% of Pu from deionized water after filtering 15 mL solutions containing 25 ppm and 33 ppb of the actinides, correspondingly. The sorption capacity of the polymers for uranium could be measured as 1mg U per mg of the polymer after six subsequent filtration steps. Alpha spectroscopy of the deposited actinides revealed peculiarities of the structural organization of polymers and their complexes with U or Pu, depending on the approach. Though both approaches were efficient, the second approach (deposition of the polymer on the membrane followed by filtration) has an additional advantage of protecting the membrane pores from capillary collapse by filling them with the polymer chains. Therefore, these polymer-modified membranes could be used either in continuous or multi-step filtration process with drying after each step without deterioration of their sorption characteristics

New Efficient Organic Scintillators Derived from Pyrazoline

We report on the synthesis, spectroscopic and scintillation properties of three new pyrazoline core based fluorophores. Fluorescence properties of the fluorophores have been studied both in a solution state and in a solid polyvinyltoluene (PVT) resin matrix of different porosity. The synthesized fluorophores were found to be promising candidates for application in plastic scintillators for detection of ionizing radiation (alpha, beta particles, γ rays and neutrons) and demonstrated superior efficiency in comparison to the existing commercially used fluorophores (2-(1-naphthyl)-5-phenyloxazole (αNPO), 9,10-diphenylanthracene, etc.). Moreover, the suggested synthetic route allows functionalization of the fluorophores with a vinyl group for further covalent bound to the PVT or other vinyl polymer matrices, which dramatically improves chemical stability of the system simultaneously improving the photoluminescence quantum yield. Possible mechanisms of the enhanced scintillation properties are discussed based on preliminary quantum mechanical calculations and spectroscopic characteristics of the fluorophores under study

The use of specialized software for liquid radioactive material spills simulation to teach students and postgraduate students

The study proves relevance of specialized software use to solve problems of emergencies prevention of radioactive liquids spills to teach students and graduate students. Main assessment criteria of accidents at radiation-hazardous objects associated with radioactive liquids spillage is identified. A model of radioactive substances transport in emergency rooms is developed. It takes into account physical features of radioactive liquid spill from the source, air pollution during transition of radioactive liquid from the spill surface into the air and subsequent scattering in the emergency room under influence of local air flows. It is determined that the existing software tools for radiation exposure assessment do not comprehensively cover features of such events and possess number of shortcomings regarding accidents modeling with spillage of radioactive liquids indoors. Computer modeling and forecasting examples for hypothetical event related to liquid radioactive spill in the JRODOS system are presented. The training process of future specialists, specialties 183 “Environmental Protection Technologies”, 143 “Nuclear Energy”, 103 “Earth Sciences”, and 122 “Computer Science” should be based on application of powerful scientific and methodological training base using modern achievements in the field of digital technologies. It is advisable to supplement curricula for students` and postgraduate students’ preparation in the mentioned above specialties by studying issues related to: development of mathematical models and software for solving problems of emergencies prevention in case of radioactive liquids spills; usage of features of specialized decision software of emergencies prevention during spills of radioactive liquids

Evolution and Interdependence of Structure and Properties of Nanocomposites of Multiwall Carbon Nanotubes with Polyaniline

Structure–property relationships of nanocomposites of multiwall carbon nanotubes (MWCNTs) and polyaniline (PANI) doped with dodecylbenzenesulfonic acid (DBSA) are studied and discussed in terms of contribution of the PANI phase properties. Two phases of PANI-DBSA with different properties, such as a shell-wrapping carbon nanotube and separate neat PANI-DBSA domains, are revealed for the first time in the nanocomposites with a high or medium PANI-DBSA content. In the nanocomposites with lower PANI-DBSA contents (<40 wt %), only a core–shell morphology with ∼3 nm or lower thickness PANI shell on the nanotubes is observed. Under this condition, the degree of crystallinity of the PANI-DBSA shell increases almost 2-fold, and thermal stability of the nanocomposite grows sharply. As compared with the neat PANI-DBSA, this special PANI shell phase has more perfect molecular structure and is characterized by a reduced amount of DBSA. It is found that the latter is caused by a competition between the processes of doping of the formed PANI in the shell by the protonic acid and p-doping caused by the MWCNT surface. The nanocomposites demonstrate ppm/ppb range sensitivity to ammonia/methylamine gases with response times, which inversely depend on the PANI-DBSA contents and thickness of the shell