Imaging the 2013 explosive crater excavation and new dome formation at Volcán de Colima with TerraSAR-X, time-lapse cameras and modelling

The summit region of steep volcanoes hosting lava domes often displays rapid geomorphologic and structural changes, which are important for monitoring the source region of hazards. Explosive crater excavation is often followed by new lava-dome growth, which is one of the most dynamic morphometric changes that may occur at volcanoes. However, details of these crater formations, and the ensuing new dome growth remain poorly studied. A common problem is the lack of observational data due to hazardous field access and the limited resolution of satellite remote sensing techniques. This paper describes the destructive-constructive crater activity at Volcán de Colima, Mexico, which occurred between January and March 2013. The crater geometry and early dome formation were observed through a combination of high-resolution TerraSAR-X spotmode satellite radar images and permanently installed monitoring cameras. This combined time-lapse imagery was used to identify ring-shaped gas emissions prior to the explosion and to distinguish between the sequential explosion and crater excavation stages, which were followed by dome growth. By means of particle image velocimetry, the digital flow field is computed from consecutive camera images, showing that vertical dome growth is dominant at the beginning. The upward growth is found to grade into spreading and a lateral growth domain. After approximately two months of gradually filling the excavated craters with new magma, the dome overflows the western margin of the crater and develops into a flow that produces block and ash flow hazards. We discuss and compare the observations to discrete element models, allowing us to mimic the vertical and lateral growth history of the dome and to estimate the maximum strength of the bulk rock mass. Moreover, our results allow a discussion on the controls of a critical dome height that may be reached prior to its gravitational spreading

Application of Fickian and non-Fickian diffusion models to study moisture diffusion in asphalt mastics

The objective of this study was to investigate certain aspects of asphalt mastic moisture diffusion characteristics in order to better understand the moisture damage phenomenon in asphalt mixtures. Moisture sorption experiments were conducted on four asphalt mastics using an environmental chamber capable of automatically controlling both relative humidity (85 %) and temperature (23 °C). The four mastics tested were identical in terms of bitumen type (40/60 pen), bitumen amount (25 % by of wt% total mix), mineral filler amount (25 % by wt%) and fine aggregate amount (50 % by wt%). The materials differed in terms of mineral filler type (granite or limestone) and fine aggregate type (granite or limestone). Preliminary data obtained during the early part of the study showed certain anomalous behavior of the materials including geometry (thickness)-dependent diffusion coefficient. It was therefore decided to investigate some aspects related to moisture diffusion in mastics by applying the Fickian and two non-Fickian (anomalous) diffusion models to the moisture sorption data. The two non-Fickian models included a two-phase Langmuir-type model and a two-parameter time-variable model. All three models predicted moisture diffusion in mastics extremely well (R 2 > 0.95). The observed variation of diffusion coefficient with thickness was attributed in part to microstructural changes (settlement of the denser fine aggregates near the bottom of the material) during the rather long-duration diffusion testing. This assertion was supported by X-ray computed tomography imaging of the mastic that showed significant accumulation of aggregate particles near the bottom of the sample with time. The results from the Langmuir-type model support a two-phase (free and bound) model for moisture absorbed by asphalt mastic and suggests about 80 % of absorbed water in the free phase remain bound within the mastic. The results also suggest that moisture diffusion in asphalt mastic may be time-dependent with diffusion decreasing by about four times during a typical diffusion test lasting up to 500 h. The study concludes that both geometry and time-dependent physical characteristics of mastic are important factors to consider with respect to moisture diffusion in asphalt mastics

Synthesis of Janus compounds for the recognition of G-U mismatched nucleobase pairs

The design and synthesis of two Janus-type heterocycles with the capacity to simultaneously recognize guanine and uracyl in G-U mismatched pairs through complementary hydrogen bond pairing is described. Both compounds were conveniently functionalized with a carboxylic function and efficiently attached to a tripeptide sequence by using solid-phase methodologies. Ligands based on the derivatization of such Janus compounds with a small aminoglycoside, neamine, and its guanidinylated analogue have been synthesized, and their interaction with Tau RNA has been investigated by using several biophysical techniques, including UV-monitored melting curves, fluorescence titration experiments, and 1H NMR. The overall results indicated that Janus-neamine/guanidinoneamine showed some preference for the +3 mutated RNA sequence associated with the development of some tauopathies, although preliminary NMR studies have not confirmed binding to G-U pairs. Moreover, a good correlation has been found between the RNA binding affinity of such Janus-containing ligands and their ability to stabilize this secondary structure upon complexation

A Self-Assembling Lanthanide Molecular Nanoparticle for Optical Imaging

Chromophores that incorporate f-block elements have considerable potential for use in bioimaging applications because of their advantageous photophysical properties compared to organic dye, which are currently widely used. We are developing new classes of lanthanide-based self-assembling molecular nanoparticles as reporters for imaging and as multi-functional nanoprobes or nanosensors for use with biological samples. One class of these materials, which we call lanthanide "nano-drums", are homogeneous 4d-4f clusters approximately 25 to 30 angstrom in diameter. These are capable of emitting from the visible to near-infrared wavelengths. Here, we present the synthesis, crystal structure, photophysical properties and comparative cytotoxicity data for a 32 metal Eu-Cd nano-drum [Eu8Cd24L12(OAc)(48)] (1). We also explored the imaging capabilities of this nano-drum using epifluorescence, TIRF, and two-photon microscopy platforms.Welch Foundation F-816, F-1018, F1515Ministry of High Education (MOHE), Malaysia under High Impact Research (HIR) - MOHE project UM.C/625/1/HIR/MoE/CHAN/13/6 H-50001-00-A000034NIH/NIAID 1U01AI078008-3Centre for Blast Injury Study at Imperial College LondonCPRIT R1003NIH-NCI CA68682National Institutes of HealthNational Science FoundationCancer Prevention Research Institute of TexasNational Science Foundation CHE-0741973Chemistr

Machine learning for estimation of building energy consumption and performance:a review

Ever growing population and progressive municipal business demands for constructing new buildings are known as the foremost contributor to greenhouse gasses. Therefore, improvement of energy eciency of the building sector has become an essential target to reduce the amount of gas emission as well as fossil fuel consumption. One most eective approach to reducing CO2 emission and energy consumption with regards to new buildings is to consider energy eciency at a very early design stage. On the other hand, ecient energy management and smart refurbishments can enhance energy performance of the existing stock. All these solutions entail accurate energy prediction for optimal decision making. In recent years, articial intelligence (AI) in general and machine learning (ML) techniques in specic terms have been proposed for forecasting of building energy consumption and performance. This paperprovides a substantial review on the four main ML approaches including articial neural network, support vector machine, Gaussian-based regressions and clustering, which have commonly been applied in forecasting and improving building energy performance

Absence of detectable precursory deformation and velocity variation before the large dome collapse of july 2015 at volcan de Colima, Mexico

Improving the ability to foresee volcanic eruption is one of the main objectives of volcanologists. For this purpose, it is essential to better detect eruption forerunners and to understand their relationship with eruptive processes. The evaluation of the performance of the forecasting methods partly relies on the estimation of the frequency of occurrence of the various precursory phenomena. Possible lack of precursor before some events must also be carefully documented and analyzed. In this study, we check for the existence of detectable precursors before the large dome collapse event of Volcan de Colima, which occurred in July 2015, leading to the emplacement of more than 10 km long Pyroclastics Density Currents and the opening of a large breach in the crater. Based on volumes of emitted magma, the 2015 eruption is the largest event recorded at Volcan de Colima since the 1913 Plinian eruption. Surface displacements in the summit cone area are quantified over the period November 2014-June 2015 based on Synthetic Aperture Radar (SAR) images acquired by Sentinel-1 satellite. Velocity variations are investigated by coda wave interferometry. Daily cross-correlation functions of seismic noise recorded at 5 broadband stations are calculated for the period January 2013-April 2017 and apparent velocity variations are obtained by applying the stretching method. We show that no significant surface deformation can be measured by the SAR images over an area reaching 5 km from the summit, such that the volume of emitted magma cannot have been accommodated elastically in the 6 months preceding the eruption at a depth shallower than 5 km. The time series of apparent velocity variations display fluctuations of the order of 0.05% with characteristic time shorter than 1 month. Sharp velocity decreases of up to 0.2% are associated with strong regional tectonic earthquakes. However, no velocity change with amplitude larger than the noise level is observed before the July 2015 eruption. The behavior of the surface deformation and the velocity variation is consistent with the relative quiescence of the volcano-tectonic and low-frequency seismic activities observed before this large eruptive event. This situation could be frequent in case of so called open systems, where additional magma input is directly transferred to the surface, producing dome modification, without significant pressurization of the plumbing system

Long-period seismicity during magma movement at Volcan de Colima

During the period from February to September 2005, Volcan de Colima produced 30 Vulcanian explosions of sufficient magnitude to produce pyroclastic flows of variable size, with a total volume of at least 2.5 x 10(6) m(3). Swarms of long-period events were associated with each event, their duration ranging from about 6 h to 3 days and each swarm containing up to 886 events. The characteristics of the swarms have been studied to understand the source mechanism and their relationship with the Vulcanian explosions. In total, 12,548 long-period events were analysed using various comparative and statistical methods. Patterns were not apparent in the data with no correlation between different properties of the swarms (duration, magnitude or frequency of occurrence of LP events) and the magnitude of the associated Vulcanian explosion, whether recorded by seismicity, volume of pyroclastics or altitude of the eruption column. This, along with other characteristics of the swarms, such as the continuation of the swarm after the explosion, with an increase in long-period event amplitude in some cases, suggests that the mechanism is not merely associated with the pressurization under an impermeable cap and resulting pressure differentials between adjacent volumes within the system. It is more likely that the production of long-period events is dominated by brittle fracturing on the margins of an ascending magma body. A model is proposed whereby the unloading above the ascending magma column produced by a Vulcanian explosion resulted in an increase in ascent rate, reflected in the increasing amplitude of long-period events. The results reflect the complexity of non-linear processes involved during magma ascent, degassing, crystallization and rupture of the impermeable plug during the Vulcanian process. At Volcan de Colima, as at many volcanoes, long-period events represent a useful precursor for eruptive activity. For monitoring, this paper highlights some useful analyses that can be carried out, which could illustrate certain characteristics of an eruptive episode. A preliminary model is presented of the conduit processes at work during the cyclic extrusive and explosive activity during 2005