193 research outputs found
Feeling Good in the Place We Live: The Moderating Role of the Perception of Environmental Resources in the Relationship between Values and Personal and Family Well-Being
The environmental psychological literature suggested that three different value orientations (egoistic, altruistic, and biospheric) are relevant for understanding environmental beliefs and intentions. We surveyed 365 Italian adults of different ages (range 18–87) to examine whether the egoistic, altruistic, and biospheric value orientations can lead to personal and/or family-related well-being. Additionally, it is examined whether the perception of presence and accessibility of two types of environmental resources (natural and urbanistic) related to ecosystem services can moderate the relation between value orientations and personal and family well-being. Results of moderation analyses showed that people with high biospheric values felt themselves as more satisfied if they perceived high and medium (but not low) presence or accessibility of natural resources in their environment, while people with high egoistic values perceived their family more satisfied if they perceived the high and medium (but not low) presence of good infrastructures in their environment of living. No significant moderation model emerged considering the participants’ altruistic values. The implications for environmental beliefs and well-being are discussed
Debris flow susceptibility mapping using the Rock Engineering System (RES) method: a case study
The main purpose of the present study is to develop a debris flow susceptibility map of a mountain area (Susa Valley, Western Italian Alps) by using an upgraded version of the Bonetto et al. (Journal of Mountain Science 18, 2021) approach based on the Rock Engineering System (RES) method. In particular, the area under investigation was discretized in a 5 × 5-m grid on which GIS based analyses were performed. Starting from available databases, several geological, geo-structural, morphological and hydrographical predisposing parameters were identified and codified into two interaction matrices (one for outcropping lithologies and one for Quaternary deposits), to evaluate their mutual interactions and their weight in the susceptibility estimation. The result for each grid point is the debris flow propensity index (DfPI), an index that estimates the susceptibility of the cell to be a potential debris flow source. The debris flow susceptibility map obtained was compared with those obtained from two expedited and universally recognized
susceptibility methods, i.e. the Regional Qualitative Heuristic Susceptibility Mapping (RQHSM) and the Likelihood Ratio (LR). Each map was validated by using the Prediction Rate Curve method. The limitations and strong points of the approaches analysed are discussed, with a focus on the innovativeness and uniqueness of the RES. In fact, in the study site, the RES method was the most efficient for the detection of potential source areas. These results prove its robustness, cost-effectiveness and speed of application in the identification and mapping of sectors capable of triggering debris flow
A new approach for the synthesis of ZnO nanoparticles sensitized with metal chalcogenides
The present communication is a response to renewed interest in nanostructure based "coupled compounds", like ZnO-MeX (where Me = Cd, Pb,... and X = S, Se) which can find extensive use in the fabrication of a number of solid state devices, such as photoconductive, solar cells, electroluminescent cells, photocatalysts. Various oxide semiconductors, like TiO2 and ZnO, are known to have appropriate properties for these applications, although there are some drawbacks associated with their use: (i) charge carrier recombination occurs within a few nanoseconds, (ii) band edge absorption threshold does not allow the utilization of visible light. One of the main approaches to overcome these particular limitations involves the contact of the semiconductor particle with another semiconductor, called "sensitizer". For example, this is the case of nanostructured ZnO particles combined with metal chalcogenides. Infact it is known that in these coupled systems the absorption threshold is extended to the visible region and the photogenerated electrons are quickly transferred from sulphide/selenide layer into to the lower lying conduction band of ZnO, thus limiting recombination effects. In order to produce this type of material we have combined ZnO nanoparticles, in the specific "tetrapod" morphology, with nanoparticles of metal chalcogenides. The main innovative aspects of the preparation procedure are the following:  the use of appropriate organic solvents to keep both ZnO and the formed metal chalcogenides completely suspended and dispersed in the liquid;  an in situ direct formation of metal chalcogenides keeping pH value in the range 6-8 (no use of ammonia salt or complexing agents);  the limited use of chemical reagents, i.e. only metal and sulphur/selenium precursors are involved;  the possibility to deposit the "coupled compounds" in form of thin films directly from the liquid suspension onto the substrates (silicon, alumina, glass, TCO layers, etc.). This paper reports details on the preparation procedure, results of morphological and structural investigations (XRD, SEM), compositional analysis (EDS microanalysis) and optical-electrical measurements (I-V, impedance spectroscopy, etc.), which point out the great potentiality of the proposed method for the synthesis of different "sensitized nano-compounds"
Climate change aggravating migration and health issues in the African context:The views and direct experiences of a community of interest in the field
Climate change is an increasingly important theme in Africa, where a large majority of its people depend on livestock and agricultural activities for livelihood. Concurrently, the topic of health of migrants and people on the move is rapidly raising both in the health debate and migration governance agenda in the Region. The link with climate change from the perspective of health and migration experts needs to be systematically addressed. Objectives: The article aims to contribute to the discourse on the interrelation of climate change, migration, and health by providing contributions of experts in the field of health and migration directly working with migrant and refugee communities in Africa. Methods: A webinar was conducted to collect and discuss first-hand experience with 25 participants from a postgraduate online course on health and migration funded by the Austrian Government and implemented in a co-operation of the Center for Health and Migration, Austria, with Makerere University, Uganda, the International Organization for Migration – UN Migration, and Lancet-Migration. As a result from the discussions, two cases from Sudan and Zimbabwe were selected to be further analysed with desk research to illustrate and underpin the points made. Results: All webinar participants reported to encounter climate change effects on health and migration in their professional practice. In their experience, climate change aggravates issues of health and migration by fueling forced migration and displacement, increasing health care needs, and deteriorating access to health care. Specific health challenges were identified for mental health problems caused by effects of climate change-induced migration, which remain widely undiagnosed and untreated, and the special affectedness of women and girls, with their mental, sexual and reproductive health severely deteriorated in insecure environments. The case studies from Sudan and Zimbabwe underline these observations. Conclusions: The interplay of effects of climate change, (internal) migration, and health is reported by a community of experts in the field of health and migration who are residing in Africa and working with migrant communities. Webinars prove to be an easy to implement tool to collect first hand evidence from practice experts, to foster exchange of experiences, and to get people engaged in further collaboration and discussion.</p
Enhanced aldehydes detection by ZnO nano-tetrapod based gas sensors
Metal oxides are very important materials in gas-sensing and the possibility to obtain them as crystalline nanostructures represents an essential chance to improve sensors sensitivity an lifetime. Zinc oxide (ZnO) is a versatile material that is today widely studied because of the large number of possible application fields. The availability of this material in a large number of nanostructures makes it very interesting for the realization of gas sensors. In this field ZnO nano-tetrapods can find a suitable and reliable application, since they can be obtained by vapour phase growth, starting from metallic Zn, with very large yield and low production costs. In the present work authors report the excellent results obtained in: (i) developing an optimized growth process for the production of ZnO tetrapods, (ii) realizing a gas sensing device based on these nanostructures and (iii) the very promising results obtained in the detection of some volatile organic compounds (VOC). In particular a very high response and a remarkable sub-ppm detection limit is demonstrated for aldehydes. Furthermore, the reaction mechanisms, which take place on the surface of ZnO tetrapods, are discussed as a function of temperature and it is shown that the response curves measured at different temperatures can provide a powerful tool for adding selectivity to aldehydes detection towards particular interfering compounds (e.g. alcohols)
Influence of Ambient Humidityon The Conductivity of CH3NH3SnCl3 Hybrid Films
Organic-inorganic (CnH2n+1NH3)2MX4 hybrid perovskites (M=divalent metal, X=halide) are attracting much attention, due to their unique electronic properties and excellent film processability [1]. The Sn based CH3NH3MX3 compounds are a subclass of that hybrid family, with cubic structure, where the organic component is included in the extended three-dimensional inorganic cage. Studies concerning the structural properties of these compounds [2] prove that methylammonium ions are orientationally disordered due to their polar character. On cooling the disorder is removed through one or more phase transitions, that usually determine large conductivity variations. However, the chemical instability is a major problem for accurate transport measurements on Sn hybrids. Furthermore, most of reported conductivity results refer to iodine-based hybrids, that are conductive, while Br- and Cl- compounds are semiconducting or insulating. In this communication we study the influence of ambient humidity on the electrical properties of thermally ablated CH3NH3SnCl3 films. In particular we show that conductivity increases by more than four orders of magnitude when relative humidity increases from 0 to 80%. Measurements performed in sequence give reproducible results, thus indicating that conductivity increase does not originate from irreversible reactions between hybrid and water vapour. We investigate the mechanisms responsible for the conductivity increase by studying the DC and AC characteristics of two contact planar devices as a function of the relative humidity. The results of impedance spectroscopy measurements are interpreted by suitable equivalent circuits that allow us to study the dipendence of the different circuit components on relative humidity. On this base we discuss the device characteristics and suggest novel insights into humidity sensing properties of CH3NH3SnCl3 films
The challenge for large-scale vapor-phase growths of not-catalyzed ZnO nanostructures: purity vs. yield
ZnO nanostructures are today a very important research topic because their proved (or even just "potential") properties promoted huge studies in many different application fields, such as optoelectronics, photovoltaics, spintronics, gas sensing, photocatalysis, piezo-electric applications, etc. Since a reproducible large-scale production is essential for a likely use of these nanostructures in any industrial application, large efforts have been done to control and stabilize their synthesis processes. Good results have been obtained in vapor phase growths of nanorods and nanowires, by mean of metal catalysts (such as Au, Pt or Ni particles). On the other side, large and controlled production of some ZnO nanostructures have been realized by wet chemical processes. Unfortunately both these approaches are intrinsically affected by the introduction of impurities in the nanocrystals\u27 structure. Indeed, even very low impurity levels may have a strong effect on the physical properties of these semiconducting nanostructures. Catalyst-free vapor-phase growth techniques should not be affected by the same impurity levels if high purity sources and gases are employed. Unfortunately, the synthesis control is generally more difficult in this kind of processes. In the present work authors show the results obtained in the optimization of three different growth processes, for a large-scale oriented production of (i) ZnO tetrapods, (ii) ZnO nanorods and (iii) ZnO long nanowires. All the described processes share a catalyst-free growth and the use of high purity metallic Zn, O2 and inert carrier gas (Ar) only. The properties of the obtained ZnO nanostructures have been characterized and, hence, pros and cons of the used approach have been discussed
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