Comparison of aerosol products retrieved from AERONET, MICROTOPS and MODIS over a tropical urban city, Pune, India

Aerosol Optical Depth (AOD) measurements from Aerosol Robotic NETwork (AERONET; level 2.0), Microtops - II sun-photometer and MODerate Resolution Imaging Spectroradiometer (MODIS) (Terra and Aqua; level 2, collection 5, dark target) were compared and used to characterize aerosols over Pune, India. AODs from Microtops and MODIS were compared with those measured by AERONET to evaluate the measurement quality. To the best of our knowledge, this is the first systematic comparison of MODIS aerosol products over Pune, India. The results of the analysis show that during 2008-10, 68 to 84 of the MODIS AODs fell within an expected error, as defined by the MODIS science team, and thus the retrievals from this system are validated and accepted. In addition, during pre-monsoon periods MODIS retrievals are better-matched with ground-based measurements. On the seasonal scale, MODIS retrievals corroborate well with ground-based measurements, with correlation coefficients ranging from 0.62 to 0.93. Despite an overall satellite-ground agreement, MODIS tends to under-estimate AOD during winter, and this may be due to improper assumptions of surface reflectance and the incorrect selection of aerosol types. AERONET retrieved single scattering albedo (SSA) values in winter (0.82-0.86), suggesting the dominance of absorbing aerosols, slightly increased (0.87-0.89) in pre-monsoon season, indicating more scattering type of aerosols. These values are about 8.9-1.1 lower than those of the assumed SSA values in the MODIS algorithm

Atomically dispersed Pt-N-4 sites as efficient and selective electrocatalysts for the chlorine evolution reaction

Chlorine evolution reaction (CER) is a critical anode reaction in chlor-alkali electrolysis. Although precious metal-based mixed metal oxides (MMOs) have been widely used as CER catalysts, they suffer from the concomitant generation of oxygen during the CER. Herein, we demonstrate that atomically dispersed Pt-N-4 sites doped on a carbon nanotube (Pt-1/CNT) can catalyse the CER with excellent activity and selectivity. The Pt-1/CNT catalyst shows superior CER activity to a Pt nanoparticle-based catalyst and a commercial Ru/Ir-based MMO catalyst. Notably, Pt-1/CNT exhibits near 100% CER selectivity even in acidic media, with low Cl- concentrations (0.1M), as well as in neutral media, whereas the MMO catalyst shows substantially lower CER selectivity. In situ electrochemical X-ray absorption spectroscopy reveals the direct adsorption of Cl- on Pt-N-4 sites during the CER. Density functional theory calculations suggest the PtN4C12 site as the most plausible active site structure for the CER

En undersökning av samspelet mellan grafiska gränssnitt, huvudrörelser och dess inverkan för användarupplevelsen i virtuell verklighet

I denna rapport undersöks samspelet mellan grafiska gränssnitt, huvudrörelser och dess inverkan för användarupplevelsen i virtuell verklighet. Studien begränsas till applicering i fastighetsvisningsapplikationer i virtuell verklighet. Studien och rapportens syfte är att besvara frågeställningen: Vilka aspekter bör tas i åtanke vid utformningen av grafiska gränssnitt för huvudrörelsebaserade inmatningsmetoder till VR-mjukvara. Denna fråga kommer besvaras med designriktlinjer orienterade för virtuell verklighet. I bakgrunden presenteras definitioner och användning av termer som: Virtuell verklighet, grafiska gränssnitt, inmatningsmetoder och huvudrörelseinmatning. I bakgrunden presenteras även företagssamarbetet med Wec360 samt riktlinjer om grafiska gränssnitt i virtuell verklighet som ligger till grund för studiens innehåll. Därefter följer ett metodkapitel som presenterar, definierar samt förklarar användning av de test- och utvärderingsmetoder som används i kommande tester. Dessa tester och utvärderingar är en heuristisk utvärdering för att finna primära problemområden som ligger som bas för kommande användbarhetstest. Men innan dess utfördes en semistrukturerad intervju med fem(5) personer som är utan, eller har mindre erfarenhet av virtuell verklighet. Dessa intervjuer utfördes för att få en grundlig idé om preferens, attityd, beteende, användning, erfarenhet samt preliminära tankar. Med samma fem deltagare utfördes ett användbarhetstest vars primära syfte var att säkerställa eller dementera de problem som uppfattades under den heuristiska utvärderingen. Användbarhetstestet användes även för att upptäcka nya problemområden som ska analyseras. Därefter följde en analys som följde bottom up-metoden för att ta alla delade problem och föra samman till en helhetsbild som studiens resultat därefter baseras på. Därefter följer resultatet – tre riktlinjer med mål att förbättra aspekter för det grafiska gränssnittet och huvudrörelseinmatning med syfte att förbättra användarupplevelsen. De främsta resultaten visas gälla applikationens sämre synlighet av interaktiva grafiska element. Men även en inkräktande upplevelse bildad av grafiska förflyttningselement. Det slutliga resultatet berörde hjälpavsnitt och hur användaren visas var funktioner och element finns i applikationen samt hur de används. Slutligen följer slutsatser och tillhörande diskussion för vidare studier inom området för användarupplevelse och grafiska gränssnitt i virtuell verklighet

Fractal dimensions of convective clouds around Delhi

Clouds exhibit fractal structure over wide ranges of scale. Following the method suggested by Lovejoy [Science (USA), 216 (1982) 185], fractal analysis of convective clouds, observed within 100 km around Delhi during the monsoon season (July-September) of 1977, has been carried out. The study is based on the radar observations collected with a high power 3-cm weather radar. A total number of 2568 radar echoes of convective clouds having areas between 4 and 7420 km2 were analysed for studying the relationship between their perimeters (P) and areas (A). The analysis showed that the relationship between the above two echo parameters can well be represented by a formula P∼AD/2, where D is described as the fractal dimension of the cloud echo perimeter. However, it was found that the two fractal dimensions of the perimeters are required to describe the above perimeter-area relationship applicable for the entire range of cloud echo area. That is, D =1.34 for cloud echoes having areas up to 600 km2 and D =1.79 for echoes having areas greater than 600 km

A survey on energy estimation and power modeling schemes for smartphone applications

SummaryIn the last decade, the rising trend in the popularity of smartphones motivated software developers to increase application functionality. However, increasing application functionality demands extra power budget that as a result, decreases smartphone battery lifetime. Optimizing energy critical sections of an application creates an opportunity to increase battery lifetime. Smartphone application energy estimation helps investigate energy consumption behavior of an application at diversified granularity (eg, coarse and fine granular) for optimal battery resource use. This study explores energy estimation and modeling schemes to highlight their advantages and shortcomings. It classifies existing smartphone application energy estimation and modeling schemes into 2 categories, ie, code analysis and mobile components power model–based estimation owing to their architectural designs. Moreover, it further classifies code analysis–based modeling and estimation schemes in simulation‐based and profiling‐based categories. It compares existing energy estimation and modeling schemes based on a set of parameters common in most literature to highlight the commonalities and differences among reported literature. Existing application energy estimation schemes are low‐accurate, resource expensive, or non‐scalable, as they consider marginally accurate smart battery's voltage/current sensors, low‐rate power capturing tools, and labor‐driven lab‐setting environment to propose power models for smartphone application energy estimation. Besides, the energy estimation overhead of the components power model–based estimation schemes is very high as they physically run the application on a smartphone for energy profiling. To optimize smartphone application energy estimation, we have highlighted several research issues to help researchers of this domain to understand the problem clearly.As shown in figure, this paper discusses energy estimation methods and techniques for energy estimation of smartphone applications. It estimates energy consumption of applications based on smartphone components power models or source code energy models. It proposes taxonomies and highlights open research issues. It concludes that energy estimation is a resource expensive task owing to high profiling overhead