1,721,091 research outputs found
Applications of radiation chemistry in the fields of industry, biotecnology and environment
No full textThe chemical effects of high energy radiations, such as those emitted by radioactive substances, generated by high-energy machines and nuclear reactors, concern a branch of chemistry called Radiation Chemistry. This term was proposed by Milton Burton in 1942 for the needs of the Manhattan Project, the secret atomic energy research program carried out in the United States during the Second World War. It is interesting to notice, however, that the first radiation-chemical change was observed as early as 1895 by Röntgen when he established the existence of a penetrating, invisible radiation – X rays – able to fog a photographic plate. Indeed, as Burton wrote (C&EN, 1969, Feb. 10, 86): In May 1942, the title Radiation Chemistry did not exist ... I sought an appropriate name for an area that we quickly realized has existed for 47 years without any name at all. The name Radiation Chemistry came out of the hopper; I didn’t like it; I asked Robert Mulliken advice. He couldn’t think of anything better and, with that negative endorsement, the old field received its present name.
Since that time, radiation chemistry has developed at an incredible rate. For at least 30 years, the interest focused on basic research, exploiting steady state and time resolved techniques, in the field not only of chemistry, but also physics and biology. These studies, reported in a large number of papers and books, enabled to understand the mechanisms of a wide variety of radiolytically induced reactions, and to collect kinetic data and absorption spectra of the unstable species formed by the interaction of high energy radiations with very different systems, as far as chemical composition and aggregation state are concerned.
Very soon, however, it was realized that the chemical changes induced by such kind of radiations in substrates of various nature could profitably be used from the applicative point of view. The first applications were in medicine for diagnostic and therapeutic purposes, but a variety of interesting industrial applications rapidly emerged, such as sterilization of different materials and polymer preparation, modification and degradation. The applicative aspect of radiation chemistry strongly expanded, taking also advantage of the great amount of results provided by basic studies, so as today high energy radiations are employed with various aims in several other fields like environment, biotechnology, cultural heritage and food treatment.
These spectacular advances are illustrated in the present volume of the Topics in Current Chemistry series that collects contributions from the most prominent expert groups. It indeed reports the outstanding developments in the industrial, biotechnological and environmental fields facing several recent and interesting topics.
They are (a) radiation induced degradation of organic pollutants in waters and wastewaters, (b) advantages of radiation technology for upgrading and refining high viscous oils and petroleum products, (c) use of gamma radiations for treating cultural heritage, (d) application of radiation chemistry to solve some technological issues related to nuclear energy, (e) radiation induced grafting for the functionalization and development of smart polymeric materials, (f) radiation engineering of multifunctional nanogels, (g) chitosan-based matrices prepared by gamma irradiation for tissue regeneration, (h) electron beam technology for environmental pollution control, (i) radiation technology applications in the food industry, and (j) application of radiation sources and accelerators in the field of space research and industry.
We believe that this volume represents a good opportunity not only to make known to non-experts the research activities carried out by exploiting the peculiar features of the high-energy radiation, but also to stimulate the interest of a wide range of readers for this quite new field.
Finally, we would like to express our gratitude to the colleagues who committed to contribute high-quality chapters, and to the editorial staff at Springer for their support throughout the development of this volume.
Margherita Venturi (University of Bologna)
Mila D’Angelantonio (ISOF-CNR Bologna
Finalmente il Nobel per la Chimica alla Chimica, ma ...
Full text linkGrande esultanza in ambito chimico per l’assegnazione del Nobel di quest’anno che, finalmente, ha premiato una tematica di grande rilevanza e specificità chimica: progettazione e sintesi di macchine molecolari. Peccato, però, che ancora una volta l’Accademia svedese si sia dimenticata dell’Italia
Insegnare Scienze: qualche considerazione metodologica, ma non solo
No full textNonostante le scienze incuriosiscano i giovani perché hanno il fascino della scoperta e dell’ignoto, il loro insegnamento/apprendimento è in crisi a livello nazionale ed internazionale, soprattutto per quanto riguarda la scuola secondaria di secondo grado. Evidentemente nelle aule non si mantiene, o addirittura si perde, questa naturale e buona disposizione verso le discipline scientifiche che, purtroppo, viene sostituita da un atteggiamento, da parte degli studenti, disinteressato e poco motivato alla curiosità e alla conoscenza. Emerge, quindi, l’esigenza di riflettere sui modi di guardare all’insegnamento delle discipline scientifiche e sul modo di vedere il ruolo che lo studente può svolgere durante la sua esperienza scolastica; in altre parole, è necessario ri-vedere le scelte professionali alla luce di consapevolezze e modelli di riferimento espliciti
Chimica e Creatività
Full text linkLa chimica non solo è una scienza centrale, perché tutti i processi che sostengono la vita sono basati su reazioni chimiche e tutte le cose che usiamo quotidianamente sono composti chimici naturali o artificiali, ma è anche l’unica disciplina scientifica che opera su tre livelli: il livello macroscopico, il livello ultramicroscopico e quello simbolico. La chimica è un mondo fantastico popolato da un numero incredibile di oggetti nanometrici chiamati molecole, le entità più piccole che hanno forme, dimensioni e proprietà distinte. Le molecole sono le parole della materia e la loro importanza è chiaramente dimostrata dal fatto che la maggior parte delle altre scienze è stata permeata dal linguaggio delle molecole. Come le parole, le molecole contengono informazioni specifiche che vengono rivelate quando interagiscono tra loro, o quando sono stimolate da fotoni o elettroni. I chimici sono nati come esploratori della Natura scoprendo e identificando milioni di molecole naturali; ben presto però sono diventati anche inventori di molecole artificiali e oggi continuano a svolgere questo duplice ruolo. Ma questo non è ancora tutto, perché recentemente i chimici, lavorando come ingegneri a livello molecolare, hanno imparato ad assemblare molecole e a creare sistemi supramolecolari che possono comportarsi come dispositivi e macchine nanometrici. Questo approccio molecola per molecola apre prospettive completamente nuove allo sviluppo delle nanotecnologie
La quantità di sostanza( o quantità chimica) e la sua unità di misura la mole: la loro storia e le novità nel nuovo sistema internazionale, in "Chimica: Cosa insegnare ai vari livelli scolastici, metodologie didattiche (anche non formali), approccio integrato all’insegnamento", Margherita Venturi
No full textInsegnare Scienze: qualche considerazione metodologica, ma non solo
No full textEven if science stimulates the curiosity of young people because it has the charm of discovery and the unknown, the teaching/learning of the scientific disciplines is in crisis at national and international level, particularly as far as high school is concerned. Obviously, in the classrooms, the natural and good disposition of young students towards scientific disciplines is not maintained, or even totally lost. It emerges, therefore, the need to reflect on ways of looking at the teaching of scientific disciplines and how to see the role that the student can play during his schooling experience. In other words, it is necessary to reconsider professional choices in the light of explicit awareness and reference models.
In order to ensure that students understand the language and the ways of operating science, the literature, both scientific and pedagogical, suggests: 1) to exploit hands-on inquiry-based learning, b) to address issues associated with the daily realities and in the social context, and c) to use an interdisciplinary approach. These three aspects will be discuss in the present contributio
Dethreading Processes of Rotaxanes -Supporting Information (article DOI: 10.1002/cphc.201501160)
No full textSupporting information for the article Dethreading of a photoactive azobenzene-containing molecular axle from a crown ether ring: a computational investigationby Gloria Tabacchi · Serena Silvi · Margherita Venturi · Alberto Credi ·Ettore FoisDOI: 10.1002/cphc.201501160</div
La natura e le abilità del pensiero scientifico
Full text linkIl laboratorio è un luogo dove si impara a costruire conoscenze e ad interiorizzare modalità di ragionamento adeguate all’ambito disciplinare grazie al fatto che abbiamo potuto sperimentare, mettere alla prova, discutere cioè fare esperienza di un’attività argomentativa reale con gli altri
Light-operated machines based on threaded molecular structures
No full textRotaxanes and related species represent the most common implementation
of the concept of artificial molecular machines, because the supramolecular nature of
the interactions between the components and their interlocked architecture allow a
precise control on the position and movement of the molecular units. The use of light
to power artificial molecular machines is particularly valuable because it can play the
dual role of “writing” and “reading” the system.Moreover, light-driven machines can
operate without accumulation of waste products, and photons are the ideal inputs to
enable autonomous operation mechanisms. In appropriately designed molecular
machines, light can be used to control not only the stability of the system, which
affects the relative position of the molecular components but also the kinetics of the
mechanical processes, thereby enabling control on the direction of the movements.
This step forward is necessary in order to make a leap from molecular machines to
molecular motors
L’avventura del progetto IRRESISTIBLE Insegnanti, studenti ed esperti a confronto su temi di ricerca d’avanguardia e aspetti della Ricerca e Innovazione Responsabile nei curricula scolastici
Full text linkÈ possibile insegnare scienze in modo nuovo introducendo nei programmi scolastici temi di ricerca d’avanguardia e sviluppando nei giovani la consapevolezza delle relazioni esistenti tra ricerca scientifica e società?
Il progetto IRRESISTIBLE e l’Università di Bologna dimostrano che, con l’aiuto di scienziati e ricercatori e con l’ausilio di metodologie didattiche innovative, non solo si tratta di una strada percorribile, ma anche che i risultati sono ottimi; gli studenti hanno, infatti, scoperto che la scienza non è qualcosa da studiare sui libri, ma una componente essenziale e ineludibile della nostra vita quotidiana
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