Rats rely heavily on tactile information from their whiskers to acquire information about their surroundings. A whisker has no sensors along its length. Instead, mechanical deformation of the whisker is sensed via receptors at its base. The present study introduces a micro-sensor developed specifically to imitate the sensing of biological rat whiskers. The sensor responds to bending moments resulting from touch and/or airflow in two axes. The sensor was designed based on analytical models from cantilever beam theory, and the models were validated with finite-element analysis. Sensors were then fabricated using micro-milled molds and integrated into an Arduino-based circuit for simple signal acquisition. The present work begins to develop the technology to allow investigation of important engineering aspects of the rat vibrissal system at 1x scale. In addition to its potential use in novel engineering applications, the sensor could aid neuroscientists in their understanding of the rat vibrissal-trigeminal pathway.
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Simplified Sensing and In-situ Measuring Approach for Building Window Properties
Windows and glazing systems play an important role in making an energy-efficient home. A portable easy-to-use in-situ measuring system of the window properties using low-cost Arduino platforms and compatible sensors is developed, 3D-printed, and then fabricated in this project and used to measure the parameters including U-factor, Solar Heat Gain Coefficient (SHGC), and Visible Light Transmittance (VT). Comparing resultant output from the developed Arduino sensing and measurements to professional in-situ instruments, we demonstrate that this simple and compact Arduino-based instrument can obtain major window properties with reasonable accuracy. This simple but scalable sensing and measuring approach and Do-It-Yourself (DIY) fabrication workflow could be performed by creative people and even homeowners without needing complex training and building physics knowledge.
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- Award ID(s):
- 1635089
- NSF-PAR ID:
- 10093239
- Date Published:
- Journal Name:
- PLEA 2018
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Tropical ecosystems are undergoing unprecedented rates of degradation from deforestation, fire, and drought disturbances. The collective effects of these disturbances threaten to shift large portions of tropical ecosystems such as Amazon forests into savanna‐like structure via tree loss, functional changes, and the emergence of fire (savannization). Changes from forest states to a more open savanna‐like structure can affect local microclimates, surface energy fluxes, and biosphere–atmosphere interactions. A predominant type of ecosystem state change is the loss of tree cover and structural complexity in disturbed forest. Although important advances have been made contrasting energy fluxes between historically distinct old‐growth forest and savanna systems, the emergence of secondary forests and savanna‐like ecosystems necessitates a reframing to consider gradients of tree structure that span forest to savanna‐like states at multiple scales. In this Innovative Viewpoint, we draw from the literature on forest–grassland continua to develop a framework to assess the consequences of tropical forest degradation on surface energy fluxes and canopy structure. We illustrate this framework for forest sites with contrasting canopy structure that ranges from simple, open, and savanna‐like to complex and closed, representative of tropical wet forest, within two climatically distinct regions in the Amazon. Using a recently developed rapid field assessment approach, we quantify differences in cover, leaf area vertical profiles, surface roughness, albedo, and energy balance partitioning between adjacent sites and compare canopy structure with adjacent old‐growth forest; more structurally simple forests displayed lower net radiation. To address forest–atmosphere feedback, we also consider the effects of canopy structure change on susceptibility to additional future disturbance. We illustrate a converse transition—recovery in structure following disturbance—measuring forest canopy structure 10 yr after the imposition of a 5‐yr drought in the ground‐breaking Seca Floresta experiment. Our approach strategically enables rapid characterization of surface properties relevant to vegetation models following degradation, and advances links between surface properties and canopy structure variables, increasingly available from remote sensing. Concluding, we hypothesize that understanding surface energy balance and microclimate change across degraded tropical forest states not only reveals critical atmospheric forcing, but also critical local‐scale feedbacks from forest sensitivity to additional climate‐linked disturbance.
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Chinese Dynamic penetration test (DPT) is an in-situ testing with the advantages of simple apparatus, economical test, and continuous data acquisition, especially for measuring bearing capacity, relative density and classification of gravelly soils. The typical gravelly soils sites are selected from the Chengdu Plain in China and the river bed of Echo dam downstream in the U.S., and China-US dynamic penetration testing and hammer energy measurements are conducted. The results show that: (1) The average of energy transfer ratios is 90% and the standard deviation is 7.7%, derived from 1321 energy time-history records, tested at 3 gravelly soils sites in the Chengdu Plain. The deviation is greatly affected by operation procedure. (2) The DPT test depth, using US drill rig assembling with Chinese DPT cone, can reach as much as 20 meters for assessing soil properties. (3) The average of energy transfer ratios is around 74% and the standard deviation is 8.7%, derived from 1438 energy time-history records, tested at 2 gravelly soils sites on the river bed of Echo dam downstream. The deviation is greatly affected by friction of drill rod and rope. (4) The DPT blows should be corrected according to different hammer energies. The proposed evaluation method for gravelly soils liquefaction, developed from the DPT database of gravelly soils liquefied during 2008 Wenchuan Earthquake, can be applicable for worldwide use.more » « less
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Abstract Sensitivity of forest mortality to drought in carbon‐dense tropical forests remains fraught with uncertainty, while extreme droughts are predicted to be more frequent and intense. Here, the potential of temporal autocorrelation of high‐frequency variability in Landsat Enhanced Vegetation Index (EVI), an indicator of ecosystem resilience, to predict spatial and temporal variations of forest biomass mortality is evaluated against in situ census observations for 64 site‐year combinations in Costa Rican tropical dry forests during the 2015 ENSO drought. Temporal autocorrelation, within the optimal moving window of 24 months, demonstrated robust predictive power for in situ mortality (leave‐one‐out cross‐validation
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Measuring the organization of the cellular cytoskeleton and the surrounding extracellular matrix (ECM) is currently of wide interest as changes in both local and global alignment can highlight alterations in cellular functions and material properties of the extracellular environment. Different approaches have been developed to quantify these structures, typically based on fiber segmentation or on matrix representation and transformation of the image, each with its own advantages and disadvantages. Here we present AFT − Alignment by Fourier Transform , a workflow to quantify the alignment of fibrillar features in microscopy images exploiting 2D Fast Fourier Transforms (FFT). Using pre-existing datasets of cell and ECM images, we demonstrate our approach and compare and contrast this workflow with two other well-known ImageJ algorithms to quantify image feature alignment. These comparisons reveal that AFT has a number of advantages due to its grid-based FFT approach. 1) Flexibility in defining the window and neighborhood sizes allows for performing a parameter search to determine an optimal length scale to carry out alignment metrics. This approach can thus easily accommodate different image resolutions and biological systems. 2) The length scale of decay in alignment can be extracted by comparing neighborhood sizes, revealing the overall distance that features remain anisotropic. 3) The approach is ambivalent to the signal source, thus making it applicable for a wide range of imaging modalities and is dependent on fewer input parameters than segmentation methods. 4) Finally, compared to segmentation methods, this algorithm is computationally inexpensive, as high-resolution images can be evaluated in less than a second on a standard desktop computer. This makes it feasible to screen numerous experimental perturbations or examine large images over long length scales. Implementation is made available in both MATLAB and Python for wider accessibility, with example datasets for single images and batch processing. Additionally, we include an approach to automatically search parameters for optimum window and neighborhood sizes, as well as to measure the decay in alignment over progressively increasing length scales.more » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- The DOI is not currently available.
