Time-resolved prompt-gamma activation analysis at spallation neutron sources and applications to cultural heritage, security, and radiation protection

Abstract The present and future developments of time-resolved prompt-gamma activation analysis (T-PGAA) at pulsed neutron sources is discussed in the framework of the successful history of neutron-activation techniques. A brief description of the state of the art and the most important user facilities using standard prompt-gamma activation analysis (PGAA) is provided. Then, we discuss the challenges and the opportunities for T-PGAA at pulsed neutron sources, and the potential impact for applications to cultural heritage, radiation protection, and security. We notice some inversions of trend needed for the further development of T-PGAA with epithermal and fast neutrons, such as the possibility to use fast and high-efficiency γ-ray scintillators with lower energy resolution (compared to usual high-purity germanium detectors) when the signal from neutron capture resonance is selected. We also suggest how detection systems often used in other fields, such as medical physics, can be of interest and inspiration also in the case of neutron-based investigations. Finally, we present new data of T-PGAA measurements on VESUVIO using neutron energies up to the keV using the scintillators available on the instrument, for samples of gold (of interest in cultural heritage), cadmium (for environmental safety), and tantalum (a material used in biomedical implants)

Upscaling of SMA film-based elastocaloric cooling

A new concept of upscaling a shape memory alloy (SMA) film based elastocaloric cooling device is presented by arranging SMA films in parallel to increase the specific cooling capacity at low actuation force, while maintaining the large surface-to-volume ratio needed for rapid heat transfer. Selected materials are cold-rolled TiNiFe films that exhibit maximum adiabatic temperature changes of 27.3 and -18.1 K upon loading and unloading, respectively. Demonstrators are designed, fabricated and characterized consisting of five free-standing TiNiFe film bridges that are coupled antagonistically for work recovery. Thermomechanical cycling is performed by out-of-plane deflection of the SMA bridges, while heat transfer is established through mechanical contact with solid heat sink/source elements. The cooling capacity of the demonstrators scales with the number of active SMA films, which confirms the concept of parallelization for upscaling. Investigated demonstrators reach a maximum cooling capacity of about 900 mW compared to a maximum of about 200 mW achieved for reference devices consisting of a single TiNiFe film. The investigation also reveals a number of open issues related to narrow fabrication tolerances upon upscaling, which may cause different plastic straining and varying inhomogeneous stress accumulation among the individual SMA films

Gamma background characterization on VESUVIO: before and after the moderator upgrade

n/

Towards energy efficient, comfortable and climate resilient built environment: Development and application of smart, optimized and mitigation-oriented solutions

Questa tesi riporta una serie di attività di ricerca che indagano, sotto diversi aspetti spaziali e temporali, i temi di efficienza energetica, comfort e resilienza al cambiamento climatico relativi al settore edilizio. Il primo macroblocco tematico è incentrato sul design di logiche di controllo ottimizzate a servizio di svariati componenti edilizi, nella fattispecie: radiatori elettrici (logiche on-off, PID e fuzzy), finestre (algoritmi di comfort adattivi basati su qualità dell’aria e comfort termico), serre solari (ventilazione meccanica controllata a logica termoigrometrica) e ventilconvettori (modelli fuzzy e predittivi per la gestione degli apporti solari). Il secondo macroblocco indaga le ripercussioni del cambiamento climatico sulla performance energetica ed ergonomica dell’ambiente costruito, partendo dal singolo edificio fino a coinvolgere fenomenologie su scala urbana. Vengono dapprima presentati i risultati dello studio di quattro mesi condotto su territorio europeo nell’ambito dell’edizione 2015 del WISBA (Wienerberger Sustainable Building Academy): la resilienza di un edificio low-tech (rappresentato dal Building 2226, Austria) è investigata nel contesto delle condizioni climatiche attese nel 2050 per approdare ad una strategia di redesign anti obsolescenza prematura. In seguito, sono esposti e discussi i risultati di uno dei progetti di mitigazione dell’effetto isola di calore urbana, condotti in collaborazione con la University of New South Wales (Sydney, Australia): il caso limite rappresentato da una capitale tropicale (Darwin) è oggetto di monitoraggio, analisi, modellazione e sviluppo di contromisure specifiche. Nel complesso, l’intero percorso di ricerca mira a definire e testare su campo soluzioni ad elevato potenziale di risparmio energetico e comfort (indoor ed outdoor) tramite logiche smart e tecnologie orientate alla mitigazione dei fenomeni di surriscaldamento globale. Comun denominatore è l’inclusione di una robusta fase sperimentale.This thesis addresses a series of research activities spanning the different spatial and temporal aspects of energy efficiency, comfort and climate change resilience throughout diverse scales of the built environment. The first macro-topic deals with the design of optimized control logics of specific building components, notably: electric radiators (on-off, PID and fuzzy controllers), windows (indoor air quality and thermal comfort driven adaptive comfort algorithm), sunspaces (smartly controlled mechanical ventilation) and fan coil units (fuzzy and model-predictive logics to counteract overabundant solar gains). The second macro-topic focuses on how climate change phenomena impinge on the energetic and ergonomic performance of buildings and cities. Firstly, the outcomes of the four-month experience in Europe, as a member of the 2015 WISBA edition (Wienerberger Sustainable Building Academy), are presented: the low-tech concept of Building 2226 (Austria) was tested in the frame of the actual climatic conditions and in view of the expected climate change to come in 2050. A re-design strategy was developed to enhance its resilience. Secondly, the results of one of the Urban Heat Island (UHI) mitigation projects run during the last year in collaboration with the University of New South Wales (Sydney, Australia) are illustrated and discussed: the borderline case of a tropical city (Darwin, Northern Territory) was monitored, analysed, modelled and tackled by developing customized counterbalance measures. Indeed, the overarching aim of the whole research path is to provide and field-test smart, optimized and mitigation-oriented solutions towards more efficient and liveable indoor and outdoor spaces. Special focus was given to the collection of on-site validated data, by planning robust monitoring campaigns and properly selecting the sensor networks

Assessing climate justice awareness among climate neutral-to-be cities

Abstract This paper sheds light on the importance of evaluating climate justice concerns when forging climate-neutral strategies at the city level. Climate justice can be a useful policy lever to develop measures that promote simultaneously greenhouse gas emissions reductions and their social justice dimension, thus reducing the risk of adverse impacts. As a result, evaluating policymakers’ awareness of (i) recognition (ii) distributive (iii) procedural, and (iv) intergenerational issues about the transition to climate neutrality might help identify where to intervene to ensure that decisions towards more sustainable urban futures are born justly and equitably. This study uses data from the European Mission on 100 Climate Neutral and Smart Cities by 2030 and a principal component analysis to build an index of climate justice awareness. It then identifies control factors behind different levels of climate justice awareness. The empirical analysis suggests that the more cities are engaged in climate efforts, the more they implement these efforts considering also the social justice dimension. It also reveals that the geographical location and the relationship with higher levels of governance contribute to shape the heterogeneity in a just-considerate climate action by virtue of different governance structures, historical legacies, and economic, cultural, and political characteristics. Overall, the analysis unveils that the availability of governmental support in capacity building and financial advisory services, and the breadth of the city’s legal powers across different fields of action are positively related to justice awareness. Conversely, the perception of favourable geo-climatic conditions is negatively correlated. These relationships can be read as assistance needs that cities perceive in their pathway to just climate neutrality and highlight where future efforts in research and policy-making should focus in the following years to pave the way to a just transition

Comfort e qualità dell’aria per le nuove scuole smart: un innovativo sistema di apertura automatizzata delle finestre

Le aule scolastiche sono un ambiente estremamente delicato sia perché rappresentano il secondo posto, dopo le mura domestiche, dove bambini e ragazzi trascorrono maggior tempo, sia per l’elevata densità di occupazione nelle aule. L’edificio scolastico dovrebbe disporre di ambienti salubri, che favoriscano l’apprendimento e l’attenzione degli studenti, che riducano al minimo la proliferazione di batteri e, di conseguenza, l’assenteismo. Fattori ambientali di disturbo, come elevate temperature e scarso ricambio d’aria, possono determinare un calo di attenzione e quindi una riduzione nel rendimento. Al contrario, se le persone lavorano in un adeguato contesto psico-fisico, l’efficienza, la produttività e il livello di benessere aumentano. Negli edifici di nuova costruzione e nelle ristrutturazioni questa problematica è ulteriormente enfatizzata dall’utilizzo di involucri superisolati e serramenti a elevata tenuta all’aria. Da un punto di vista prettamente ambientale, il problema della salubrità nelle aule può essere lenito mantenendo un adeguato livello di qualità dell’aria e di comfort termico. Questo obiettivo è stato raggiunto con l’ausilio di un sistema meccanico automatizzato che ha il compito di gestire le aperture e le chiusure delle finestre secondo un opportuno algoritmo di controllo basato sul modello di comfort adattivo. Il sistema fornisce i risultati migliori quando viene affiancato ad una progettazione intelligente delle aperture vetrate, sia a livello di posizione che di tipologia: è preferibile la collocazione delle finestre sul medesimo lato, per evitare fastidiose correnti, e l’unione del sistema ad anta con sovrapposta apertura a vasistas