Inference of Room Geometry From Acoustic Impulse Responses

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Kinematic analysis of the Pakuashan fault tip fold, west central Taiwan: Shortening rate and age of folding inception

The Pakuashan anticline is an active fault tip fold that constitutes the frontal most zone of deformation along the western piedmont of the Taiwan Range. Assessing seismic hazards associated with this fold and its contribution to crustal shortening across central Taiwan requires some understanding of the fold structure and growth rate. To address this, we surveyed the geometry of several deformed strata and geomorphic surfaces, which recorded different cumulative amounts of shortening. These units were dated to ages ranging from ~19 ka to ~340 ka using optically stimulated luminescence (OSL). We collected shallow seismic profiles and used previously published seismic profiles to constrain the deep structure of the fold. These data show that the anticline has formed as a result of pure shear with subsequent limb rotation. The cumulative shortening along the direction of tectonic transport is estimated to be 1010 ± 160 m. An analytical fold model derived from a sandbox experiment is used to model growth strata. This yields a shortening rate of 16.3 ± 4.1 mm/yr and constrains the time of initiation of deformation to 62.2 ± 9.6 ka. In addition, the kinematic model of Pakuashan is used to assess how uplift, sedimentation, and erosion have sculpted the present-day fold topography and morphology. The fold model, applied here for the first time on a natural example, appears promising in determining the kinematics of fault tip folds in similar contexts and therefore in assessing seismic hazards associated with blind thrust faults

Integrated plasmonic circuitry on a vertical-cavity surface-emitting semiconductor laser platform

Integrated plasmonic sources and detectors are imperative in the practical development of plasmonic circuitry for bio- and chemical sensing, nanoscale optical information processing, as well as transducers for high-density optical data storage. Here we show that vertical-cavity surface-emitting lasers (VCSELs) can be employed as an on-chip, electrically pumped source or detector of plasmonic signals, when operated in forward or reverse bias, respectively. To this end, we experimentally demonstrate surface plasmon polariton excitation, waveguiding, frequency conversion and detection on a VCSEL-based plasmonic platform. The coupling efficiency of the VCSEL emission to waveguided surface plasmon polariton modes has been optimized using asymmetric plasmonic nanostructures. The plasmonic VCSEL platform validated here is a viable solution for practical realizations of plasmonic functionalities for various applications, such as those requiring sub-wavelength field confinement, refractive index sensitivity or optical near-field transduction with electrically driven sources, thus enabling the realization of on-chip optical communication and lab-on-a-chip devices

Utilization of LSTM neural network for water production forecasting of a stepped solar still with a corrugated absorber plate

This study introduces a long short-term memory (LSTM) neural network model to forecast the freshwater yield of a stepped solar still and a conventional one. The stepped solar still was equiped by a copper corrugated absorber plate. The thermal performance of the stepped solar still is compared with that of conventional single slope solar still. The heat transfer coefficients of convection, evaporation, and radiation process have been evaluated. The exergy and energy efficiencies of both solar stills have been also evaluated. The yield of the stepped solar still is enhanced by about 128 % compared with that of conventional solar still. Then, the proposed LSTM neural network method is utilized to forecast the hourly yield of the investigated solar stills. Field experimental data was used to train and test the developed model. The freshwater yield was used in a time series form to train the proposed model. The forecasting accuracy of the proposed model was compared with those obtained by conventional autoregressive integrated moving average (ARIMA) and was evaluated using different statistical assessment measures. The coefficient of determination of the forecasted results has a high value of 0.97 and 0.99 for the conventional and the stepped solar still, respectively