1. Field evaluation of low-cost PM sensors (Purple Air PA-II) under variable urban air quality conditions, in GreeceIasonas Stavroulas, Georgios Grivas, Panagiotis Michalopoulos, Eleni Liakakou, Aikaterini Bougiatioti, Panayiotis Kalkavouras, Kyriaki Maria Fameli, Nikolaos Hatzianastassiou, Nikolaos Mihalopoulos, Evangelos Gerasopoulos, 2020, original scientific article Abstract: Recent advances in particle sensor technologies have led to an increased development and utilization of low-cost, compact, particulate matter (PM) monitors. These devices can be deployed in dense monitoring networks, enabling an improved characterization of the spatiotemporal variability in ambient levels and exposure. However, the reliability of their measurements is an important prerequisite, necessitating rigorous performance evaluation and calibration in comparison to reference-grade instrumentation. In this study, field evaluation of Purple Air PA-II devices (low-cost PM sensors) is performed in two urban environments and across three seasons in Greece, in comparison to different types of reference instruments. Measurements were conducted in Athens (the largest city in Greece with nearly four-million inhabitants) for five months spanning over the summer of 2019 and winter/spring of 2020 and in Ioannina, a medium-sized city in northwestern Greece (100,000 inhabitants) during winter/spring 2019–2020. The PM2.5 sensor output correlates strongly with reference measurements (R2 = 0.87 against a beta attenuation monitor and R2 = 0.98 against an optical reference-grade monitor). Deviations in the sensor-reference agreement are identified as mainly related to elevated coarse particle concentrations and high ambient relative humidity. Simple and multiple regression models are tested to compensate for these biases, drastically improving the sensor’s response. Large decreases in sensor error are observed after implementation of models, leading to mean absolute percentage errors of 0.18 and 0.12 for the Athens and Ioannina datasets, respectively. Overall, a quality-controlled and robustly evaluated low-cost network can be an integral component for air quality monitoring in a smart city. Case studies are presented along this line, where a network of PA-II devices is used to monitor the air quality deterioration during a peri-urban forest fire event affecting the area of Athens and during extreme wintertime smog events in Ioannina, related to wood burning for residential heating.
Keywords: particulate matter, PM2.5, air quality, low-cost sensors, optical particle counter
Published in RUNG: 10.05.2024; Views: 965; Downloads: 6
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2. Tuning the activity of iron phosphide electrocatalysts for sustainable energy conversionSaim Emin, Takwa Chouki, Manel Machreki, 2023, published scientific conference contribution abstract (invited lecture) Abstract: Electrocatalysis is a promising approach for the sustainable conversion of renewable energy sources, such as solar and wind power, into chemical energy that can be stored and used on demand. By harnessing renewable electricity to drive electrochemical reactions, we can produce fuels and chemicals in a way that is both clean and cost-effective. As we continue to develop new electrocatalytic materials and improve the efficiency of existing processes, the potential for electrocatalysis to transform our energy system will only continue to grow.
We report the use of iron phosphide (Fe2P, FeP) in several electrocatalytic applications, such as reduction of nitrate ions (NO3), hydrogen and oxygen evolution studies. The electrochemical reduction of the nitrate ion (NO3), a widespread water pollutant, to valuable ammonia (NH3) is a promising approach to achieving green energy conservation. Particularly, FeP and Fe2P phases were successfully demonstrated as efficient catalysts for NH3 generation. Detection of the in-situ formed product using a bi-potentiostat was achieved by electrooxidation of NH3 to nitrogen (N2) on a Pt electrode. The Fe2P catalyst exhibits the highest Faradaic efficiency (96%) for NH3 generation with a yield (0.25 mmol h−1 cm-−2 or 2.10 mg h−1 cm−2) at −0.55 V vs. reversible hydrogen electrode (RHE). To get relevant information about the reaction mechanisms and the fundamental origins behind the better performance of Fe2P, density functional theory (DFT) calculations were performed.
Keywords: Fe2P, FeP, electrocatalysis, NH3 reduction, counter electrode
Published in RUNG: 04.12.2023; Views: 1746; Downloads: 5
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3. Efficient Iron Phosphide Catalyst as a Counter Electrode in Dye-Sensitized Solar Cells : articleAbdullah Yildiz, Takwa Chouki, Aycan Atli, Moussab Harb, Sammy W Verbruggen, Rajeshreddy Ninakanti, Saim Emin, 2021, original scientific article Abstract: Developing an efficient material as a counter electrode (CE) with excellent catalytic activity, intrinsic stability, and low cost is essential for the commercial application of dye-sensitized solar cells (DSSCs). Transition metal phosphides have been demonstrated as outstanding multifunctional catalysts in a broad range of energy conversion technologies. Here, we exploited different phases of iron phosphide as CEs in DSSCs with an I–/I3–-based electrolyte. Solvothermal synthesis using a triphenylphosphine precursor as a phosphorus source allows to grow a Fe2P phase at 300 °C and a FeP phase at 350 °C. The obtained iron phosphide catalysts were coated on fluorine-doped tin oxide substrates and heat-treated at 450 °C under an inert gas atmosphere. The solar-to-current conversion efficiency of the solar cells assembled with the Fe2P material reached 3.96 ± 0.06%, which is comparable to the device assembled with a platinum (Pt) CE. DFT calculations support the experimental observations and explain the fundamental origin behind the improved performance of Fe2P compared to FeP. These results indicate that the Fe2P catalyst exhibits excellent performance along with desired stability to be deployed as an efficient Pt-free alternative in DSSCs.
Keywords: Iron phosphide, catalyst, counter electrode, dye-sensitized solar cell, solvothermal synthesis
Published in RUNG: 06.02.2023; Views: 2118; Downloads: 0
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4. Counter-regime Photography Under FascismMartina Caruso, 2011, independent scientific component part or a chapter in a monograph Abstract: The role of counter-regime, or humanist, photography in Italy under fascism is considered through the critical themes of ruralism, masculinity and war, revealing its significant, although hidden, role in the history of postwar humanist photography.
Keywords: humanist photography, counter-regime, Fascist regime, Mussolini, ruralism, masculinity, war, postwar
Published in RUNG: 13.01.2023; Views: 1845; Downloads: 0
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6. Post Colonial Dilettantes : The Aesthetics Of Anti-ImperialismRajat Sharma, 2018, master's thesis Abstract: The thesis begins a discourse into a need of an Indian film theory by exploring and
analysing the plenitude of relevant western theories. In order to do so it lays down certain
concrete relationships between ideologies, terminologies and their effect; as in what
exactly post colonial means, why it is important to understand the impact of colonisation
on culture and thus on one of the most mass consumed medium in India; films. The thesis
explores the depths and complexity of the relationship of these two and the other
influences that sprout from it for example the intensity of colonisation as a cultural project
and its influence on the social reality of the people, artists, thinkers (and in our case
specifically filmmakers) , who in turn reflect on this culture through various mediums
including films. The thesis examines the western plethora of film theory in order to
accentuate the contrast between film and cinema in the west and east and thus the
subsequent need to bring forth a new ‘Eastern Film theory’.
Keywords: Post Colonialism, Cultural genocide, Cinematic Apparatus, Baudry, Political cinema, Brecht, Counter Cinema, Feminist film theory, Laura Mulvey, Douchet, Lacan, Anti Imperialism, Third Cinema, Solanas and Getino, Third Manifesto, Indian Cinema, Satyajit Ray, Consumerism
Published in RUNG: 19.11.2018; Views: 5371; Downloads: 168
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