11 Works

Simplified Green-Ampt model, imbibition-based estimates of permeability, and implications for leak-off in shale reservoirs

Tetsu Tokunaga
Predicting water imbibition into porous materials is important in a wide variety of fields, yet is often challenging because of uncertainties in both the permeability and capillary pressure driving force. Here, this uncertainty is reduced through evaluating correlations between the permeability and the effective capillary pressure associated with the wetting front, Pc,f. These correlations allow elimination of Pc,f from the Green and Ampt equation, and concentrates all uncertainties in fluxes on the effective permeability k....

SVACH - Development of advanced smart ventilation controls for residential applications

Brennan Less, Iain Walker, David Lorenzetti & Michael Sohn
This study examined the use of zoned ventilation systems using a coupled CONTAM/EnergyPlus model for new California dwellings. Several smart control strategies were developed with a target of halving ventilation-related energy use, largely through reducing dwelling ventilation rates based on zone occupancy. The controls were evaluated based on the annual energy consumption relative to continuously operating non-zoned, code-compliant mechanical ventilation systems. The systems were also evaluated from an indoor air quality perspective using the equivalency...

Redefining Near-Unity Luminescence in Quantum Dots with Photothermal Threshold Quantum Yield

David Hanifi, Noah Bronstein, Brent Koscher, Zach Nett, Joseph Swabeck, Kaori Takano, Adam Schwartzberg, Lorenzo Maserati, Koen Vandewal, Yoeri Van De Burgt, Alberto Salleo & Paul Alivisatos
Herin is the code and example data sets for the publication titled: "Redefining Near-Unity Luminescence in Quantum Dots with Photothermal Threshold Quantum Yield." The abstract of this paper is as follows. A variety of optical applications rely on the absorption and reemission of light. The quantum yield of this process often plays an essential role. When the quantum yield deviates from unity by significantly less than 1%, applications such as luminescent concentrators and optical refrigerators...

Automating the interpretation of PM2.5 time-resolved measurements using a data-driven approach

Wanyu Chan, Hao Tang & Michael Sohn
The rapid development of automated measurement equipment enables researchers to collect greater quantities of time-resolved data from indoor and outdoor environments. The interpretation of the resulting data can be a time-consuming effort. This dataset contains the R code and time-resolved indoor and outdoor PM2.5 data to illustrate a machine learning approach called Random Forest (RF). The method is used to study a dataset of 836 emission events that occurred over a two-week period, each in...

Current limits on determination of protonation state using neutron macromolecular crystallography

Dorothee Liebschner
Neutron diffraction is a technique used to locate hydrogen and and deuterium atoms at medium data resolution in macromolecular structures. Typically, the structures are not determined de novo; instead, the structure has been previously determined with X-ray diffraction. The Protein Data Bank (PDB) was parsed to find homologue models for all neutron structures. The data table lists PDB IDs for X-ray structures that are similar to neutron models deposited in the PDB (as of October...

Data from: Indoor air quality in California homes with code-required mechanical ventilation

Wanyu Chan, Yang-Seon Kim, William Delp, Iain Walker & Brett Singer
Data were collected in 70 detached houses built in 2011-2017 in compliance with the mechanical ventilation requirements of California’s building energy efficiency standards. Each home was monitored for a one-week period with windows closed and the central mechanical ventilation system operating. Pollutant measurements included time-resolved fine particulate matter (PM2.5) indoors and outdoors and formaldehyde and carbon dioxide (CO2) indoors. Time-integrated measurements were made for formaldehyde, NO2 and nitrogen oxides (NOX) indoors and outdoors. Operation of...

High-throughput Synthesis and Transformations of CsPbBr nanocrystals characterized by UV-Vis Absorption and Fluorescence

Jakob C Dahl, Xingzhi Wang, Emory M. Chan & A. Paul Alivisatos
These experiments are a dataset of absorption and photoluminescence emission spectra of cesium lead bromide nanocrystals synthesized under different conditions, published as a companion dataset for “Elucidating the Weakly Reversible Cs-Pb-Br Perovskite Nanocrystal Reaction Network with High-Throughput Maps and Transformations” (https://doi.org/10.1021/jacs.0c04997). It also includes deconvolution of the absorption and emission spectra and other calculations, and a notebook including the deconvolution algorithm and some helpful visualization code.

Impacts of Mixed-Wettability on Brine Drainage and Supercritical CO2 Storage Efficiency in a 2.5-D Heterogeneous Micromodel

Chun Chang, Timothy Kneafsey, Jiamin Wan, Tetsu Tokunaga & Seiji Nakagawa
Geological carbon storage (GCS) involves unstable drainage processes that affect CO2 storage efficiency and plume distribution. Drainage is greatly complicated by the mixed-wet nature of rock surfaces common in hydrocarbon reservoirs where supercritical CO2 (scCO2) is used in enhanced oil recovery. We performed scCO2 injection (brine drainage) experiments at 8.5 MPa and 45 °C in heterogeneous micromodels, two mixed-wet with varying water- and intermediate-wet patches, and one water-wet. The flow regime changes from capillary fingering...

Indoor air quality in new and renovated low‐income apartments with mechanical ventilation and natural gas cooking in California

Haoran Zhao, Wanyu Chan, Sebastian Cohn, William W. Delp, Iain S. Walker & Brett C. Singer
This study presents pollutant concentrations and performance data for code-required mechanical ventilation equipment in 23 low-income apartments at 4 properties constructed or renovated 2013-2017. All apartments had natural gas cooking burners. Occupants pledged to not use windows for ventilation during the study but several did. Measured airflows of range hoods and bathroom exhaust fans were lower than product specifications. Only eight apartments operationally met all ventilation code requirements. Pollutants measured over one week in each...

Thermal pressure in the laser heated diamond anvil cell: a quantitative study and implications for the density vs. mineralogy correlation of the mantle

Ethan Yen, Quentin Williams & Martin Kunz
Thermal pressure is an inevitable thermodynamic consequence of heating a volumetrically constrained sample in the diamond anvil cell. Its possible influences on experimentally determined density-mineralogy correlations are widely appreciated, yet the effect itself has never been experimentally measured. We present here the first quantitative measurements of the spatial distribution of thermal pressure in a laser heated diamond anvil cell (LHDAC) in both olivine and AgI. The observed thermal pressure is strongly localized and closely follows...

Data from: A reusable pipeline for large-scale fiber segmentation on unidirectional fiber beds using fully convolutional neural networks

Alexandre Fioravante De Siqueira, Stéfan Van Der Walt & Daniela Mayumi Ushizima
Fiber-reinforced ceramic-matrix composites are advanced materials resistant to high temperatures, with application to aerospace engineering. Their analysis depends on the detection of embedded fibers, with semi-supervised techniques usually employed to separate fibers within the fiber beds. Here we present an open computational pipeline to detect fibers in ex-situ X-ray computed tomography fiber beds. To separate the fibers in these samples, we tested four different architectures of fully convolutional neural networks. When comparing our neural network...

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