2,304 research outputs found
INTRODUZIONE AL RISCHIO DA RADIAZIONE NELL'AMBIENTE SPAZIALE
No full textL'ambiente di radiazione spaziale è molto differente da quello terrestre ed è uno dei principali ostacoli all'esplorazione umana del sistema solare. Esso infatti può potenzialmente causare effetti dannosi per la salu- te dell'astronauta, portando in casi estremi addirittura alla morte. Tra le principali componenti dell'ambiente spaziale troviamo raggi cosmici di origine extra-galattica, parti- celle emesse dal sole, particelle intrappolate dal campo magnetico planetario e particelle neutro emesse come albedo. Si ha spesso a che fare con un campo di radiazione com- plesso, in cui ogni componente è caratterizzata da diversi tipi di radiazione e energia, e di conseguenza porta a diversi tipi di effetti e necessita di differenti contromisure. Scopo di questo lavoro è riassumere le principali carat- teristiche delle due principali componenti responsabili del rischio radiazione nello spazio interplanetario: le particelle solari emesse durante le tempeste solari (Solar Particle Events - SPE) e i raggi cosmici galattici (GCR). Verrà inoltre brevemente introdotto il diverso tipo di danno biologico causato dai raggi cosmici e i principali scenari di missioni future verranno descritti
Passive shielding of space radiation for human exploration missions - Simulations and Radiation Tests
No full textSpace radiation is one of the main showstoppers for human exploration of deep space.
When leaving the protection provided by Earth’s atmosphere and magnetic field, the
astronaut crew find themselves immersed into a complex radiation field, originated
by the interaction of different high-energy radiation sources with the spacecraft’s
walls, and characterized by many particle species with a broad range of energies.
The biological effects of the long-term radiation exposure is largely uncertain and
could give rise not only to late solid cancers and leukemia, but also to early effects
to cardiac and nervous tissues, possibly undermining mission success.
An available countermeasure to defend the astronauts from radiation is passive
shielding, i.e. the interposition of shielding materials between the radiation sources
and the exposed subjects. However, the majority of space radiation is practically
impossible to completely stop: the high energetic particles constituting the space
environment have the capability to penetrate several meters of materials, generating
a harmful component of secondary particles, further contributing to the radiation
dose.
The ability of a material to attenuate the incoming space radiation and the nature
of the generated secondary particles largely depends on the traversed material itself,
in particular on the ratio between its charge and mass atomic numbers, Z/A. The
lower is this ratio, the higher the material’s capability to attenuate the incoming
radiation will be, both through electromagnetic and nuclear interactions.
While the radiobiology community is focusing on the biological effects, radiation
physics is trying to lower uncertainties characterizing the radiation interactions with
materials, performing radiation measurements of various nature.
In this framework I focused my PhD activity on the study of materials which
could be used in space as shielding layers and multipurpose structures have been
evaluated and selected under different criteria. At first, their ability to shield different kinds of space radiation were calculated with the aid of 1D Monte Carlo simulations,
also followed by an evaluation of their structural and thermal proprieties, cost,
availability and compatibility with the space environment. Simulations, in particular,
were performed both to support the material selection process both to produce
guidelines for design.
The selected materials were then procured to be tested under different radiation
beams and different set-ups, in single and multi-layers configurations, in an attempt
to reproduce space exposure conditions. At the same time, the radiation tests have
been reproduced by means of Monte Carlo simulations, to compare the experimental
results and the simulations’ outputs, confirming the codes’ ability to reproduce
radiation measurements involving High Z-number and high Energy (HZE) particles.
For some materials, suggestions were provided on which nuclear model was better
reproducing the data.
The performed experimental campaign suggested that a candidate shielding
material suitable for Galactic Cosmic Rays (GCR) should be tested with at least two
beams with different characteristics, since the results indicated that some materials
good at shielding 972 MeV/nuc 56Fe ions performed very poorly when irradiated
with high energetic alphas. Furthermore, among the material types included in this
investigation work, Lithium Hydride resulted the best option to stop space radiation,
when only radiation shielding properties are considered.
At the end of the experimental campaigns, on the basis of the test results, a 3D
simulation activity has started and is still on-going and a modular space habitat
model has been created. Monte Carlo simulations have been carried out, reproducing
different Moon exposure scenarios with the goal of calculating crew radiation exposure
during a Moon surface mission. This work reports results only for a standard
aluminum habitat, with only Moon soil used as shielding material. However, future
simulations will include Lithium Hydride and possibly others materials as shielding
layers, to evaluate their effectiveness in reducing the dose in a realistic exposure
scenario. Preliminary results show that even with a heavily shielded spacecraft (the
habitat taken in consideration in this work is providing from every direction at least
30 g/cm2 of aluminum equivalent) radiation exposure approaches values close to the
existing annual radiation exposure limits.
Part of this thesis’ work was done at Thales Alenia Space, using Thales Alenia
Space infrastructures and in the framework of the ROSSINI2 study. The ROSSINI2 study has been supported by European Space Agency (ESA) under the contract
RFP IPLPTE/LF/mo/942.2014 and with the generous support of NASA and BNL,
providing beam time at the NSRL facility
Special Issue “COVID-19: Diagnostic Imaging and Beyond—Part II”
No full textMore than two years have passed since the onset of the COVID-19 pandemic [...]
Martina Drijverová and her literary works for children (author´s portrait)
No full textThis thesis Martina Drijverova and her literatur for children (the author´s portrait) is engaged in work of writer and screenwriter Martina Drijeverová. She is an excellent writer of literature for children. In the first part of this work her story writing is mentioned and the second part deals with her fairy-tale writing. The other author´s work written for children is in the third part. The conclusion of this thesis appreciates the author´s credit in literature for chidlren. Analysis of some books are available. The supplementary part is composed of autor´s biography and her photograph, some book covers, list of the autor´s work {--} televiews, radio plays and serials, audio tapes and CDs, stage plays, books written in Braille
HERStory Makers 2022: Martina Čagalj
No full textMartina Čagalj is a PhD candidate at the University of Split studying seaweeds as a potential source of bioactive compounds. She took part in HERStory Makers 2022.What is HERStory Makers?HERStory Makers is a social media competition for female-identifying early career researchers to share their research, their career journeys, and to inspire the next generation. Winners are selected by public vote. HERStory Makers is also part of EXPLORATHON, Scotland's contribution to European Researchers' Night.In 2022-23, EXPLORATHON was supported by the Engineering & Physical Sciences Research Council [grant number EP/X020894/1].Author contributions to contentMartina Čagalj conceived, planned, and recorded the video content. Kirsty Ross edited the video content to insert HERStory Maker credits, add subtitles, and maintain video length below Twitter/X limit of 2 mins and 20 secs, prior to scheduling the social media posts.</p
Is empowerment of female radiologists still needed? Findings of a systematic review
No full textConsidering that radiology is still a male-dominated specialty in which men make up more than two thirds of the workforce, this systematic review aimed to provide a comprehensive overview of the current role of women in radiological imaging, focusing on the main aspects such as career progression, leadership, academic practice, and perceived discrimination. Three electronic databases were searched up to 21 October 2020. To identify additional records, weekly automatic email alerts were set up on PubMed until December 2020 and reference lists of key studies and included papers were screened. Two reviewers independently performed the search, study selection, quality appraisal, data extraction, and formal narrative synthesis. In case of disagreement, a third reviewer was involved. Across the 61 included articles, women worked more often part-time and held fewer positions of power in hospitals, on editorial boards, and at the academic level (associate and full professors). Women were less often in relevant positions in scientific articles, had fewer publications, and had a lower H-index. Discrimination and sexual harassment were experienced by up to 40% and 47% of female radiologists, respectively. Our study highlights that women in radiology are still underrepresented and play a marginal role in the field, struggling to reach top and leading positions
Harnessing cavitational effects for green process intensification
No full textThe impressive chemico-physical effects observed in sonochemistry are a result of cavitation, as ultrasonic and hydrodynamic cavitation does not interact with matter at the atomic and molecular levels. Bubble collapse leads to the quasi-adiabatic heating of the vapour inside bubbles, giving rise to local hot spots in the fluid. Cavitation thus transforms a mechanical energy into high kinetic energy, which is released in very short bursts that are exploited for green process intensification. This paper reviews relevant applications of hydrodynamic and acoustic cavitation with the aim of highlighting the particular advantages that these phenomena offer to the intensification of green chemical processes. Emulsification, biodiesel preparation, wastewater decontamination, organic synthesis, enzymatic catalysis and extractions are discussed among others. As a comparison, hydrodynamic cavitation technique is more advantageous in dealing with process intensification at large-scale, as well as the enhancement of mass transfer and heat transfer, while ultrasonic cavitation technique is more convenient to operate, easier to control in the studies at lab-scale, and exhibits more efficient in producing active free radicals and inducing the cleavage of volatile compounds
Space Safety and Human Performance
No full textSpace Safety and Human Performance provides a comprehensive reference for engineers and technical managers within aerospace and high technology companies, space agencies, operators, and consulting firms. The book draws upon the expertise of the world’s leading experts in the field and focuses primarily on humans in spaceflight, but also covers operators of control centers on the ground and behavior aspects of complex organizations, thus addressing the entire spectrum of space actors.
During spaceflight, human performance can be deeply affected by physical, psychological and psychosocial stressors. Strict selection, intensive training and adequate operational rules are used to fight performance degradation and prepare individuals and teams to effectively manage systems failures and challenging emergencies. The book is endorsed by the International Association for the Advancement of Space Safety (IAASS)
The role of data science in software development
No full textauthor: Martina WeberMasterarbeit Universität Innsbruck 201
The role of data science in software development
No full textauthor: Martina WeberMasterarbeit Universität Innsbruck 201
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