Seismic Observations of Four Thunderstorms Using an Underground Fiber-Optic Array

Thunderstorms are a common atmospheric phenomenon that cause abundant acoustic disturbances, which can interact with the ground surface, creating a link between atmospheric and solid Earth processes. This article reports seismological observations of four thunderstorms through the spring and summer of 2019, as recorded by the distributed acoustic sensing fiber-optic array (4.9 km) on the Penn State campus in State College, Pennsylvania. With a dense sensor array in the local region, we are able to construct the seismic full waveform response of the thunderstorm events (hereafter referred to as thunderquakes) and track the wave propagation across the array. We use a time-domain grid search to obtain the back azimuth and slowness of the waves, and a modified Geiger’s method to pinpoint source locations of the thunderquakes. Correlated with the time of the recorded signal, this data allows reconstruction of thunderstorm movement as well as offering measurements of the seismic velocity.

Perceptual Narrative Layer in Muriel Spark’s Story “The Dark Glasses”

The article deals with the visual perception layer in Muriel Spark’s short story “The Dark Glasses” with the aim of carrying out a conceptual analysis of this text. Meaning generation models have already been demonstrated as multilayer non-homogeneous structures describing different points of view and different narrative layers in B. Uspensky’s, G. Genette’s and W. Schmid’s theories. The text as a complex structural language unit can, like the word, vary in different semantic fields. This article presents the spatial, temporal, ideological, and linguistic narrative layers according to the dominant visual perception layer in the protagonist-narrator’s internal point of view expressed in the story. The perceptual layer is demonstrated on the basis of the cognitive process in visual perception, namely, the optic array and human perceptual system. The optic array is implied in the story’s composition as a framed closed structure comprising two texts: the frame and the embedded text. Both of them follow the subject-object model of perception and are organized according to the principles of reflectivity, doubling, and copying. The perceptual system is expressed through various language units: simple verbal predicates see, look and a set of verbs of perception, substantives eyes, glasses and their direct (initial) and figurative meanings, colour terms based on adjectives in descriptions of the characters, as well as conceptual archetypal visual metaphors from the light–dark family, and metonymies based on causal and partitive semantic relations.

Past, Present and Future Monitoring at the Vallcebre Landslide (Eastern Pyrenees, Spain)

Works carried out to monitor the displacements of the Vallcebre landslide (Pyrenees range, NE of Spain) since 1987 are presented. The landslide, which extends over an area of about 0.8 km2 and affects more than 20 × 106 m3, has experienced displacements of up to one meter per year in some points and periods. It has been periodically monitored since 1987, using a wide range of surface and in-hole techniques: triangulation with theodolite, Terrestrial Photogrammetry, Electronic Distance Measurement, GNSS-GPS, inclinometers, wire extensometers, piezometers, DInSAR (satellite) and GBSAR (terrestrial). The results obtained using new techniques are compared with those obtained with GNSS-GPS and a wire extensometer, and checked against fixed stable points. From this comparison, we conclude that even though wire extensometers and inclinometers may have the highest precision, in practice, all systems play potentially valuable roles in providing meaningful data for monitoring at different study stages. In the near future, we envisage the installation of a Distributed Fiber Optic array to monitor the risk with a certain space and time continuity. After the evaluation of the precision and advantages of the different methods, the complementary use of some of them is strongly recommended.

A Mega-High-Throughput Screening Platform for the Discovery of Biologically Relevant Sequence-Defined Non-Natural Polymers

Combinatorial methods enable the synthesis of chemical libraries on scales of millions to billions of compounds, but the ability to efficiently screen and sequence such large libraries has remained a major bottleneck for molecular discovery. We developed a novel technology for screening and sequencing libraries of synthetic molecules of up to a billion compounds in size. This method utilizes Fiber-optic Array Scanning Technology (FAST) to screen bead-based libraries of synthetic compounds at a rate of 5 million compounds per minute (~83,000 Hz). This ultra-high-throughput screening platform has been used to screen libraries of synthetic “self-readable” non-natural polymers that can be sequenced at femtomole scale by chemical fragmentation and highresolution mass spectrometry. The versatility and throughput of the platform was demonstrated by screening two libraries of non-natural polyamide polymers with sizes of 1.77M and 1B compounds against the protein targets K-Ras, asialoglycoprotein receptor (ASGPR), IL-6, IL-6 receptor and TNFα. Hits with nanomolar binding affinities were found against all targets, including competitive inhibitors of K-Ras binding to Raf and functionally active uptake ligands for ASGPR facilitating intracellular delivery.

A Mega-High-Throughput Screening Platform for the Discovery of Biologically Relevant Sequence-Defined Non-Natural Polymers

Combinatorial methods enable the synthesis of chemical libraries on scales of millions to billions of compounds, but the ability to efficiently screen and sequence such large libraries has remained a major bottleneck for molecular discovery. We developed a novel technology for screening and sequencing libraries of synthetic molecules of up to a billion compounds in size. This method utilizes Fiber-optic Array Scanning Technology (FAST) to screen bead-based libraries of synthetic compounds at a rate of 5 million compounds per minute (~83,000 Hz). This ultra-high-throughput screening platform has been used to screen libraries of synthetic “self-readable” non-natural polymers that can be sequenced at femtomole scale by chemical fragmentation and highresolution mass spectrometry. The versatility and throughput of the platform was demonstrated by screening two libraries of non-natural polyamide polymers with sizes of 1.77M and 1B compounds against the protein targets K-Ras, asialoglycoprotein receptor (ASGPR), IL-6, IL-6 receptor and TNFα. Hits with nanomolar binding affinities were found against all targets, including competitive inhibitors of K-Ras binding to Raf and functionally active uptake ligands for ASGPR facilitating intracellular delivery.

On the Ambient Optic Array: James Gibson’s Insights About the Phenomenon of Chiaroscuro

In 1966, James Gibson first presented his theory of the ambient optic array, and he proposed a new field of ecological optics that he hoped would advance our knowledge on this topic. This study will consider how his ideas have largely come to fruition over the past 50 years. It reviews the research on the visual perception of three-dimensional shape from shading, the effects of ambient light from surface interreflections on observers’ perceptions, the perception of the light field, and the perception of surface materials. Finally, it also considers Gibson’s impact on these developments.

Comparison between Distributed Acoustic Sensing and Geophones: Downhole Microseismic Monitoring of the FORGE Geothermal Experiment

We compare the performance of a downhole distributed acoustic sensing (DAS) fiber-optic array with that of conventional geophones. The downhole collocated arrays are part of the Frontier Observatory for Research in Geothermal Energy (FORGE) geothermal experiment, in which stimulation of the rock volume in an enhanced geothermal system (EGS) causes microseismic events. The DAS acquisition system yields data sampled at every 1 m at 2000 samples per second for the entire length of the well, spanning to a depth of 985 m from the surface. Whereas single DAS channels are substantially noisier than geophones at the same location, their large number and spatial coherency allow for the application of effective array processing techniques. We follow a complete workflow for the fiber-optic array: velocity model building, event detection, event location, and magnitude estimation. Estimated velocity models agree well with sonic logging in a nearby well and map a granitic contact accurately. Detection performance is somewhat worse than geophones and yields magnitude completeness of −1.4 compared to −1.7 for geophones. Using a single vertical fiber array, we cannot retrieve the azimuth of the events relative to the well. However, we can very accurately estimate their depth and horizontal distance from the array. Magnitude estimation with DAS approaches geophone results to within a standard deviation of M=0.115 and negligible mean difference. The DAS processing results outperform a regional and local surface array, consolidated with a shallow borehole sensor. Although downhole geophones in the FORGE experimental layout performed better, DAS holds several critical practical benefits that were not demonstrated. Thanks to its heat resistance, it can be deployed much closer to the reservoir; fibers can be deployed along cased active wells, eliminating the need for a dedicated monitoring well; the permanently installed fiber can be used for years or decades. Therefore, we argue that DAS holds vast potential for long-term monitoring of EGS projects.

Rapid Yeast Cell Viability Analysis by Using a Portable Microscope Based on the Fiber Optic Array and Simple Image Processing

A fiber optic array (FOA) can be used as an alternative or a supplement to the lens in a microscope due to its large magnification, high coupling efficiency and extremely low distortion. Based on our previous research, this paper first demonstrated the resolution and field-of-view (FOV) of the microscope based on the FOA. To further validate the FOA microscope’s imaging capability, yeast activity and concentration were investigated by simple image processing. The results showed that the percentages of live and dead yeast cells correctly identified were 92.1% and 84.8%, except for the clusters, which agreed well with the manual counting methods. Then, the performances of the portable microscopes based on the FOA and lens were compared and the factors that affect the FOA microscope imaging performance were analyzed.

Microseismic monitoring using a fibre-optic Distributed Acoustic Sensor (DAS) array

We present a case study demonstrating the use of an “L”-shaped downhole fibre-optic array to monitor microseismicity. We use a relatively simple method to detect events from continuous waveform data, and develop a workflow for manual event location. Locations are defined with a cylindrical coordinate system, with the horizontal axis of the DAS cable being the axis of symmetry. Events are located using three manual “picks”, constraining (1) the zero-offset “broadside” channel to the event (2) the P-S wave arrival time difference at the broadside channel, and (3) the angle, ? of the event from the array. Because the one-component DAS array is unable to record P-wave energy on the broadside channel, the P-wave pick is made indirectly by ensuring that the modeled P- and S-wave moveout curves match the observed data. The ? angle requires that signal is observed on the vertical part of the array, in our case this is possible because an engineered fiber, rather than standard telecommunications fiber, provided a significant reduction in the noise level. Because only three picks need to be made, our manual approach is significantly more efficient than equivalent manual processing of downhole geophone data, where picks for P- and S-waves must be made for each receiver. We find that the located events define a tight cluster around the injection interval, indicating that this approach provides relatively precise and accurate event locations. A surface microseismic array was also used at this site, which detected significantly fewer events, the locations of which had significantly greater scatter than the DAS array locations. We conclude by examining some other aspects of the DAS microseismic data, including the presence of multiple events within very short time windows, and the presence of converted phases that appear to represent scattering of energy from the hydraulic fractures themselves.