Comparative genome- and proteome-wide screens yield large amounts of data. To efficiently present such datasets and to simplify the identification of hits, the results are often presented in a type ...of scatterplot known as a volcano plot, which shows a measure of effect size versus a measure of significance. The data points with the largest effect size and a statistical significance beyond a user-defined threshold are considered as hits. Such hits are usually annotated in the plot by a label with their name. Volcano plots can represent ten thousands of data points, of which typically only a handful is annotated. The information of data that is not annotated is hardly or not accessible. To simplify access to the data and enable its re-use, we have developed an open source and online web tool with R/Shiny. The web app is named VolcaNoseR and it can be used to create, explore, label and share volcano plots ( https://huygens.science.uva.nl/VolcaNoseR ). When the data is stored in an online data repository, the web app can retrieve that data together with user-defined settings to generate a customized, interactive volcano plot. Users can interact with the data, adjust the plot and share their modified plot together with the underlying data. Therefore, VolcaNoseR increases the transparency and re-use of large comparative genome- and proteome-wide datasets.
Nitrogen-doped carbon materials featuring atomically dispersed metal cations (M–N–C) are an emerging family of materials with potential applications for electrocatalysis. The electrocatalytic ...activity of M–N–C materials toward four-electron oxygen reduction reaction (ORR) to H2O is a mainstream line of research for replacing platinum-group-metal-based catalysts at the cathode of fuel cells. However, fundamental and practical aspects of their electrocatalytic activity toward two-electron ORR to H2O2, a future green “dream” process for chemical industry, remain poorly understood. Here we combined computational and experimental efforts to uncover the trends in electrochemical H2O2 production over a series of M–N–C materials (M = Mn, Fe, Co, Ni, and Cu) exclusively comprising atomically dispersed M–N x sites from molecular first-principles to bench-scale electrolyzers operating at industrial current density. We investigated the effect of the nature of a 3d metal within a series of M–N–C catalysts on the electrocatalytic activity/selectivity for ORR (H2O2 and H2O products) and H2O2 reduction reaction (H2O2RR). Co–N–C catalyst was uncovered with outstanding H2O2 productivity considering its high ORR activity, highest H2O2 selectivity, and lowest H2O2RR activity. The activity–selectivity trend over M–N–C materials was further analyzed by density functional theory, providing molecular-scale understandings of experimental volcano trends for four- and two-electron ORR. The predicted binding energy of HO* intermediate over Co–N–C catalyst is located near the top of the volcano accounting for favorable two-electron ORR. The industrial H2O2 productivity over Co–N–C catalyst was demonstrated in a microflow cell, exhibiting an unprecedented production rate of more than 4 mol peroxide gcatalyst –1 h–1 at a current density of 50 mA cm–2.
The need for disaster preparedness becomes very important in Indonesia. Due to its geographical situation, within a ring of fire, Indonesia is prone to several disasters such as earth-quake and ...volcano eruption. This paper presents the design of a context-aware system to pre-emptively notify and provide some information to the population around Merapi volcano. The information contains some dangerous area and safe-place/shelter based on the user location. The proposed design can also notify the level of danger that might be encountered by the user and the mitigation path within a certain distance.
Real-Time rendering is the technique which allows us to have graphical applications in our everyday life, whether it is a 3D game or a tool with graphical user interface. Nowadays graphics rendering ...is handled by the GPU (Graphics Processing Unit) in our device. There are many layers of abstraction above the programming of GPUs through libraries and graphics engines, though the most low-level way of accessing a GPU in user-mode applications is using a Graphics API. Due to the need of high performance and low-level capabilities usually these APIs are used from C or C++, but we realized the need to utilize these APIs in higher level languages as well.
In our approach we're using the .NET C# language for developing multi-platform real-time graphical applications instead of the C or C++ languages. Using the modern .NET environment, we're able to use Graphics APIs for rendering onto common .NET UI Frameworks while consuming all our previously implemented C# libraries and .NET technologies in the same application. To maintain compatibility with multiple platforms we're developing a library system allowing the use different Graphics APIs from the same C# source-code. The library system contains a Graphics API abstraction layer with multiple Graphics API implementations of this layer in C# and a C# to shader language compiler for cross-API shader development in C#.
In this paper, we're proposing our considerations for implementing a library to be able to use the Vulkan and OpenGL APIs through a single C# codebase. We provide solutions for multi-platform rendering and dealing with the low-level challenges of using the two deeply different APIs, while maintaining performance capable to do real-time rendering.
Nickel iron oxyhydroxide is the benchmark catalyst for the oxygen evolution reaction (OER) in alkaline medium. Whereas the presence of Fe ions is essential to the high activity, the functions of Fe ...are currently under debate. Using oxygen isotope labeling and operando Raman spectroscopic experiments, we obtain turnover frequencies (TOFs) of both Ni and Fe sites for a series of Ni and NiFe layered double hydroxides (LDHs), which are structurally defined samples of the corresponding oxyhydroxides. The Fe sites have TOFs 20–200 times higher than the Ni sites such that at an Fe content of 4.7 % and above the Fe sites dominate the catalysis. Higher Fe contents lead to larger structural disorder of the NiOOH host. A volcano‐type correlation was found between the TOFs of Fe sites and the structural disorder of NiOOH. Our work elucidates the origin of the Fe‐dependent activity of NiFe LDH, and suggests structural ordering as a strategy to improve OER catalysts.
Iron versus nickel: Turnover frequencies (TOFs) of both Ni and Fe sites in the oxygen evolution reaction (OER) catalyzed by a series of Ni and NiFe layered double hydroxides (LDHs) have been determined. Effects of structural disorder of NiOOH lattice are revealed.
Defect engineering is a versatile approach to modulate band and electronic structures as well as materials performance. Herein, metal–organic frameworks (MOFs) featuring controlled structural ...defects, namely UiO‐66‐NH2‐X (X represents the molar equivalents of the modulator, acetic acid, with respect to the linker in synthesis), were synthesized to systematically investigate the effect of structural defects on photocatalytic properties. Remarkably, structural defects in MOFs are able to switch on the photocatalysis. The photocatalytic H2 production rate presents a volcano‐type trend with increasing structural defects, where Pt@UiO‐66‐NH2‐100 exhibits the highest activity. Ultrafast transient absorption spectroscopy unveils that UiO‐66‐NH2‐100 with moderate structural defects possesses the fastest relaxation kinetics and the highest charge separation efficiency, while excessive defects retard the relaxation and reduce charge separation efficiency.
Volcano‐type trend: A series of metal–organic frameworks (MOFs) decorated with Pt nanoparticles, Pt@UiO‐66‐NH2‐X, were fabricated with increasing levels of structural defects in the MOF to investigate how defect levels affect photocatalysis. The catalysts exhibit an impressive volcano‐type trend in H2 production, maximizing at a moderate defect level.
On Dec. 22, 2018, at approximately 20:55-57 local time, Anak Krakatau volcano, located in the Sunda Straits of Indonesia, experienced a major lateral collapse during a period of eruptive activity ...that began in June. The collapse discharged volcaniclastic material into the 250 m deep caldera southwest of the volcano, which generated a tsunami with runups of up to 13 m on the adjacent coasts of Sumatra and Java. The tsunami caused at least 437 fatalities, the greatest number from a volcanically-induced tsunami since the catastrophic explosive eruption of Krakatau in 1883 and the sector collapse of Ritter Island in 1888. For the first time in over 100 years, the 2018 Anak Krakatau event provides an opportunity to study a major volcanically-generated tsunami that caused widespread loss of life and significant damage. Here, we present numerical simulations of the tsunami, with state-of the-art numerical models, based on a combined landslide-source and bathymetric dataset. We constrain the geometry and magnitude of the landslide source through analyses of pre- and post-event satellite images and aerial photography, which demonstrate that the primary landslide scar bisected the Anak Krakatau volcano, cutting behind the central vent and removing 50% of its subaerial extent. Estimated submarine collapse geometries result in a primary landslide volume range of 0.22-0.30 km
, which is used to initialize a tsunami generation and propagation model with two different landslide rheologies (granular and fluid). Observations of a single tsunami, with no subsequent waves, are consistent with our interpretation of landslide failure in a rapid, single phase of movement rather than a more piecemeal process, generating a tsunami which reached nearby coastlines within ~30 minutes. Both modelled rheologies successfully reproduce observed tsunami characteristics from post-event field survey results, tide gauge records, and eyewitness reports, suggesting our estimated landslide volume range is appropriate. This event highlights the significant hazard posed by relatively small-scale lateral volcanic collapses, which can occur en-masse, without any precursory signals, and are an efficient and unpredictable tsunami source. Our successful simulations demonstrate that current numerical models can accurately forecast tsunami hazards from these events. In cases such as Anak Krakatau's, the absence of precursory warning signals together with the short travel time following tsunami initiation present a major challenge for mitigating tsunami coastal impact.
Auf den Spuren des Empedokles Jonas Kuhn; Nicole Bobrowski; Ulrich Platt
Heidelberger Jahrbücher Online.,
10/2022, Volume:
7
Journal Article
Peer reviewed
Open access
Nirgendwo sonst auf der Erde sind sich die vier Elemente so nahe wie bei Vulkanen. Wenn heiße Magma aus der Tiefe der Erde aufsteigt gibt sie große Mengen von Gas, hauptsächlich Wasserdampf, ab. ...Sobald diese Gase an der Erdoberfläche mit Luft in Berührung kommen laufen komplexe chemische Reaktionen ab. So bildet etwa die Reaktion von magmatischem Wasserdampf mit Sauerstoff aus der Luft reaktive Molekülbruchstücke (Radikale), die im Bruchteil einer Sekunde reduzierte Bestandteile der Gasemission verbrennen. Empedokles, der Begründer der Lehre der vier Elemente, starb der Legende nach am Vulkan Ätna, als er in den Krater stieg, um das Vulkaninnere zu verstehen. Nach wie vor ist die Forschung an Vulkanen mit großen Herausforderungen verbunden: giftige Gase, hohe Vulkangipfel, sprudelnde Lava. Moderne Fernerkundungsverfahren erlauben mittlerweile die Beobachtung von chemischen Abläufen in Vulkangasen aus (halbwegs) sicherer Entfernung. Erkenntnisse daraus helfen Vulkane und unseren Planeten im Allgemeinen besser zu verstehen und bilden damit auch die Grundlage neuer Möglichkeiten Ausbrüche vorherzusagen.
Volcano analyses have been established as a standard tool in the field of electrocatalysis for assessing the performance of electrodes in a class of materials. The apex of the volcano curve, where ...the most active electrocatalysts are situated, is commonly defined by a hypothetical ideal material that binds its reaction intermediates thermoneutrally at zero overpotential, in accordance with Sabatier's principle. However, recent studies report a right shift of the apex in a volcano curve, in which the most active electrocatalysts bind their reaction intermediates endergonically rather than thermoneutrally at zero overpotential. Focusing on two‐electron process, this Viewpoint addresses the question of how the definition of an optimum catalyst needs to be modified with respect to the requirements of Sabatier's principle when kinetic effects and the applied overpotential are included in the analysis.
Tip of the volcano: Electrode materials are classically assessed by their location on a volcano curve, using the binding strength of a reaction intermediate (RI) as a descriptor. For a two‐electron process, the apex of the volcano corresponds to thermoneutral binding of the reaction intermediate at zero overpotential. This Viewpoint addresses the definition of an optimum catalyst when kinetic effects and applied overpotential are factored in, illustrating a right shift of the volcano's top with increasing driving force.
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•Continuum solvation fails to predict oxygen reduction onset potential on Pt (111).•Main issue is an underestimation of OH solvation energy.•Adding 1 or 2 explicit water molecules ...does not correct the OH solvation energy.
We present a comparison study between the implicit and explicit solvation approach for density functional theory (DFT) predictions of the oxygen reduction reaction (ORR) activity on Pt (111) and other metal surfaces under acidic conditions. DFT calculations with a self-consistent polarizable continuum model implement in VASPsol results in more accurate predictions of onset potentials for Pt(111) than vacuum DFT calculations due to the extra stabilization of the surface intermediates (OOH*, O*, OH*). Implicit solvation also preserves the scaling relationship among ORR intermediates and volcano-shape activity relationships that correlate ORR onset potential or activity to the free energy absorption of O* or OH*. Moreover, VASPsol predicts variation in the solvation energies across different surfaces, suggesting the use of universal solvation corrections may not be valid. However, VASPsol exhibits significant weaker OH* solvation energies (by ∼ 0.4 eV) on Pt (111) compared to literature values using an explicit water bilayer and therefore underestimates the onset potential on Pt (111). We attribute this lack of OH* solvation energies by VASPsol to its inability to address hydrogen bonds and the absence of intermediate stabilization of the bilayer structure. Strategies to mitigate this problem, including tuning VASPsol parameters and a hybrid approach incorporating one to two water molecules, are also examined but not found to alleviate the underestimation of the solvation of OH*.
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