Showing papers by "Pennsylvania State University published in 2023"

Differentiable modeling to unify machine learning and physical models and advance Geosciences

Abstract: Process-Based Modeling (PBM) and Machine Learning (ML) are often perceived as distinct paradigms in the geosciences. Here we present differentiable geoscientific modeling as a powerful pathway toward dissolving the perceived barrier between them and ushering in a paradigm shift. For decades, PBM offered benefits in interpretability and physical consistency but struggled to efficiently leverage large datasets. ML methods, especially deep networks, presented strong predictive skills yet lacked the ability to answer specific scientific questions. While various methods have been proposed for ML-physics integration, an important underlying theme  — differentiable modeling — is not sufficiently recognized. Here we outline the concepts, applicability, and significance of differentiable geoscientific modeling (DG). “Differentiable” refers to accurately and efficiently calculating gradients with respect to model variables, critically enabling the learning of high-dimensional unknown relationships. DG refers to a range of methods connecting varying amounts of prior knowledge to neural networks and training them together, capturing a different scope than physics-guided machine learning and emphasizing first principles. In this talk we provide examples of DG in global hydrology, ecosystem modeling, water quality simulations, etc. Preliminary evidence suggests DG offers better interpretability and causality than ML, improved generalizability and extrapolation capability, and strong potential for knowledge discovery, while approaching the performance of purely data-driven ML. DG models require less training data while scaling favorably in performance and efficiency with increasing amounts of data. With DG, geoscientists may be better able to frame and investigate questions, test hypotheses, and discover unrecognized linkages. 

Preparation of metal-organic framework from in situ self-sacrificial stainless-steel matrix for efficient water oxidation

Abstract: The oxygen evolution reaction (OER) on the anode is one of the key half-cell reactions in water electrolysis and metal-air batteries, and its reaction process is mainly hampered by sluggish kinetics and low efficiency. In this work, a series of MIL-53 metal-organic framework (MOF) derived materials grown on self-sacrificial SSM substrate was designed and synthesized for efficient water oxidation in alkaline solutions. The as-obtained FeNiBDC/SSM (SSM = stainless steel matrix and H2BDC = benzene-1,4-dicarboxylic acid) with MIL-53 MOF of uniform morphology and high porosity was successfully synthesized via a facile one-step method using recycled stainless steel as a template. Afterward, FeNiBDC/SSM was accompanied by morphological and structural changes during the OER process while the modified MOF components on the SSM substrate degraded into Fe/NiOOH species, which serve as catalytic centers. After the stability test for 100 h, the used optimal FeNiBDC/SSM2 exhibited a promising electrocatalytic OER performance with a low Tafel slope of 74.5 mV dec-1, a small overpotential of 239 mV at 10 mA cm-2, and high current retention of 95.20 %. This work provides a new research idea for the sustainable recycling of existing resources and the one-step in-situ preparation of MOF/substrate electrocatalyst for OER.

Tillage intensity and plant rhizosphere selection shape bacterial-archaeal assemblage diversity and nitrogen cycling genes

Abstract: Agroecosystem management practices, plant-microbe interactions, and climate are all factors that influence soil microbial community diversity and functionality. Herein, we assessed diversity of soil bacterial-archaeal assemblages and denitrification gene markers in a long-term tillage field experiment. We evaluated bulk and rhizosphere soils from two crop years (corn and soybean) of a three-year rotation of corn-soybean-small grain + cover crop. Soil samples were collected at three growth stages from corn and soybean plants and across three tillage practices that had been applied every year for 40 years. Tillage practices represented three levels of disturbance intensity ranging from low (no-till) to intermediate (chisel-disk) to high (moldboard plow) intensities. Bacterial assemblage diversity differed in soils having contrasting tillage histories and from bulk or rhizosphere soil (compartments), crop year, and growth stage. Compared to plowed and chisel-disked soils, no-till soils had lower abundances of denitrification genes, higher abundances of genes for dissimilatory nitrate reduction to ammonium (DNRA), and higher abundances of family-level taxa associated with archaeal nitrification and anammox. Soybean rhizospheres exerted stronger selection on bacterial-archaeal composition and diversity relative to corn rhizospheres. Abundances of N genes were grouped by factors related to weather, as well as management and soil compartment, which could impact activity related to denitrification and DNRA. Low intensity tillage may provide an option to reduce potential ‘hot spots’ or ‘hot moments’ for N losses in agricultural soils, although weather and crop type are also important factors that can influence how tillage affects microbial assemblages and microbial N use.

A Grammar-Based Approach for Generating Spatial Layout Solutions for the Adaptive Reuse of Sobrado Buildings

Abstract: This research develops a shape grammar to generate solutions for the adaptive reuse of historic buildings. More precisely, it proposes a transformation grammar for sobrado buildings, a typology present in the historic center of São Luís, Brazil. The methodology defines a workflow for adapting sobrado buildings, once characterized for single-families, into multi-family apartments considering spatial and structural requirements. The grammar specifies a framework for repurposing historic buildings into social housing and considers the allocation of three types of apartments in the floor plan: studios, one-bedroom apartments, and two-bedroom apartments. The adopted strategy for spatial planning prioritizes access to natural daylight. The grammar supports different layout solutions for the same building and aims to accelerate the reuse of historic structures for contemporary housing needs. This paper describes the grammar rules and their application to three case study buildings.

Metamorphism and Deformation on Subduction Interfaces: 2. Petrological and Tectonic Implications

Abstract: The compositional range of ∼2,000 marine sediments and ∼19,000 oceanic igneous rocks is encapsulated by a set of 12 sedimentary and 10 mafic rock compositions, allowing computation of phase relationships on P-T paths along subduction interfaces. These are described economically by a partitioning analysis, which connects the mineral assemblages to different parts of the subduction P-T space and facilitates assessment of prograde dehydration, melting, densification, and rheological systematics. Dehydration and densification occur at shallower depths than in studies that neglect shear heating. Lawsonite stability is limited to interfaces where convergence is slower than 20 mm/yr; such rates also favor transport of volatiles beyond the arc. Terrigenous sediments and mafic rocks reach their solidi close to the top of the wedge-slab interface; melt fractions are enhanced by fluid from the dehydrating slab interior. Rheological calculations show that the most abundant sediment types have interface capacities of hundreds of meters to kilometers, and that the strengths of mafic rocks comfortably exceed their buoyancy stresses. Above ∼ 650°C sediments are weak enough to rise as diapirs into the mantle wedge. Carbonate- and serpentinite-rich lithologies are weaker than other interface rocks, and ascend most rapidly at the cessation of subduction. Ascent rates drop abruptly as rocks enter the plate interface, probably leading to retrograde equilibrium at P ∼1-1.5 GPa. The seismic-aseismic transition is expected at about 500°C in mafics, and 400°C in metasediments. Seamounts are weaker than most other interface rocks, and unlikely to form asperities. Slow slip and tremor may be associated with the blueschist-eclogite transition. This article is protected by copyright. All rights reserved.

Understanding Subsurface Fracture Evolution Dynamics Using Time‐Lapse Full Waveform Inversion of Continuous Active‐Source Seismic Monitoring Data

Abstract: Predicting the behavior, geometry, and flow properties of subsurface fractures remains a challenging problem. Seismic models that can characterize fractures usually suffer from low spatiotemporal resolution. Here, we develop a correlative double-difference time-lapse full waveform inversion of continuous active source seismic monitoring data for determining high-spatiotemporal-resolution time-lapse Vp models of in-situ fracture evolution at a shallow contamination site in Wyoming, USA. Assisted by rock physics modeling, we find that (a) rapidly increasing pore pressure initializes and grows the fracture, increasing the porosity slightly (from ∼13.7% to ∼14.6%) in the tight clay formation, thus decreasing Vp (∼50 m/s); (b) the fluid injection continues decreasing Vp, likely through the introduction of gas bubbles in the injectate; and (c) final Vp reductions reach over ∼150 m/s due to a posited ∼4.5% gas saturation. Our results demonstrate that high-resolution Vp changes are indicative of mechanical and fluid changes within the fracture zone during hydrofracturing.

Unmanned aerial vehicle based tree canopy characteristics measurement for precision spray applications

Abstract: The critical components for applying the correct amount of agrochemicals are fruit tree characteristics such as canopy height, canopy volume, and canopy coverage. An unmanned aerial vehicle (UAV)-based tree canopy characteristics measurement system was developed using image processing approaches. The UAV captured images using a high-resolution red-green-blue (RGB) camera. A digital surface model (DSM) and a digital terrain model (DTM) were generated from the captured images. A tree canopy height map was generated from the subtraction of DSM and DTM. A total of 24 apple trees were randomly targeted to measure the canopy characteristics. Region of interest (ROI) was generated across the boundary of each targeted tree. The height of all pixels within each ROI was computed separately. The pixel with maximum height was considered as the height of the respective tree. For computing canopy volume, the sum of all pixel heights from individual ROI was multiplied by the square of ground sample distance (GSD) of 5.69 mm•pixel−1. A segmentation method was employed to calculate the canopy coverage of the individual trees. The segmented canopy pixel area was divided by the total pixel area within the ROI. The results showed an average relative error of 0.2 m (6.64%) while comparing automatically measured tree height with ground measurements. For tree canopy volume, a mean absolute error of 0.25 m3 and a root mean square error of 0.33 m3 were achieved. The study estimated the possible agrochemical requirement for spraying the fruit trees, ranging from 0.1 to 0.32 liter based on tree canopy volumes. The overall investigations suggest that the UAV-based tree canopy characteristics measurements could be a potential tool to calculate the pesticide requirement for precision spraying applications in tree fruit orchards.

Inferring protein fitness landscapes from laboratory evolution experiments

Abstract: Directed laboratory evolution applies iterative rounds of mutation and selection to explore the protein fitness landscape and provides rich information regarding the underlying relationships between protein sequence, structure, and function. Laboratory evolution data consist of protein sequences sampled from evolving populations over multiple generations and this data type does not fit into established supervised and unsupervised machine learning approaches. We develop a statistical learning framework that models the evolutionary process and can infer the protein fitness landscape from multiple snapshots along an evolutionary trajectory. We apply our modeling approach to dihydrofolate reductase (DHFR) laboratory evolution data and the resulting landscape parameters capture important aspects of DHFR structure and function. We use the resulting model to understand the structure of the fitness landscape and find numerous examples of epistasis but an overall global peak that is evolutionarily accessible from most starting sequences. Finally, we use the model to perform an in silico extrapolation of the DHFR laboratory evolution trajectory and computationally design proteins from future evolutionary rounds.

Thermodynamic re-modeling of the Yb-Sb system aided by first-principles calculations

Abstract: The thermodynamic description of the Yb-Sb binary system is developed by means of the CALculations of PHAse Diagrams (CALPHAD) method by combining experimental data in the literature and predictions from first-principles calculations based on density functional theory (DFT) in the literature and the present work. Two pseudopotentials of Yb are compared in the present DFT-based calculations with 14 and 13 f-electrons frozen in the core, i.e., 5p66s2 and 5p66s25 d1 electrons as valence electrons, termed Yb_2 and Yb_3, respectively. It is shown that the phonon spectrum of the YbSb phase calculated using the Yb_3 pseudopotential does not have imaginary phonon modes and is subsequently used to predict its temperature dependent thermodynamic properties by the DFT-based quasiharmonic phonon calculations. The present thermodynamic database includes the Yb16Sb11 phase in addition to five intermetallic phases that were considered in previous modeling studies, i.e., YbSb2, YbSb, Yb11Sb10, Yb4Sb3, and Yb5Sb3. The high temperature orthorhombic structure of the Yb5Sb3 phase is not considered in the present work as it was stabilized by hydrogen. The associate solution model is used to describe the short-range ordering behavior in the liquid phase. The calculations from the present thermodynamic model show good agreement with thermochemical and phase equilibrium data from both the present work and the literature.

How Healthy Older Adults Enact Lateral Maneuvers While Walking

Abstract: Abstract Background Walking requires frequent maneuvers to navigate changing environments with shifting goals. Humans accomplish maneuvers and simultaneously maintain balance primarily by modulating their foot placement, but a direct trade-off between these two objectives has been proposed. As older adults rely more on foot placement to maintain lateral balance, they may be less able to adequately adapt stepping to perform lateral maneuvers. Research Question How do older adults adapt stepping to enact lateral lane-change maneuvers, and how do physical and perceived ability influence their task performance? Methods Twenty young (21.7 ± 2.6 yrs) and 18 older (71.6 ± 6.0 yrs) adults walked on a motorized treadmill in a virtual environment. Following an audible and visual cue, participants switched between two parallel paths, centered 0.6m apart, to continue walking on their new path. We quantified when participants initiated the maneuver following the cue, as well as their step width, lateral position, and stepping variability ellipses at each maneuver step. Results Young and older adults did not differ in when they initiated the maneuver, but participants with lower perceived ability took longer to do so. Young and older adults also did not exhibit differences in step width or lateral positions at any maneuver step, but participants with greater physical ability reached their new path faster. While only older adults exhibited stepping adaptations prior to initiating the maneuver, both groups traded-off stability for maneuverability to enact the lateral maneuver. Significance Physical and perceived balance ability, rather than age per se , differentially influenced maneuver task performance. Humans must make decisions related to the task of walking itself and do so based on both physical and perceived factors. Understanding and targeting these interactions may help improve walking performance among older adults.

Beyond Making a Statement: An Intersectional Framing of the Power and Possibilities of Positioning

Abstract: In this essay, two women of Color researchers examine the intersections of race and disability and ask, “What is the power and purpose of positioning and positionality statements?” Informed by Black feminist theory, and drawing from the DisCrit tenets of intersectional oppressions, historicity, and whiteness and ability as property, the authors focus on researchers’ positioning in relation to how they engage and communicate knowledge about multiply marginalized people. Positionality statements, they argue, must be more than a listing of identities or a claim on authority through the naming of professional proximity to marginalized communities. Recognizing the increasing expectations for education scholars to articulate positionality in their scholarship, the authors offer a three-pronged intersectional framework, with provocations about the onto-epistemic, sociohistoric, and sociocultural elements of positioning. Education researchers interested in conveying how intersectional oppressions effect knowledge production will find this framework useful for crafting positionality statements that consider the multidimensional nature of power, oppression, and research in relation to their field, the literature, and multiply marginalized participants.

Racial Climates, Ecological Indifference

Abstract: Abstract Racial Climates, Ecological Indifference offers a powerful intervention to the field of climate justice scholarship by addressing a neglected aspect of the field of climate justice, namely systemic racisms. Building on the work of Black feminist theorists, the work develops an ecointersectional approach designed to reveal the depth and complexities of racial climates overlooked even in the environmental justice literature. The book’s conception of ecological indifference underscores the disposition of seeing the environment as a resource for human consumption and enjoyment, a resource that is usable, fungible, disposable, and without intrinsic worth or standing. The many examples in the book offer new insights demonstrating that systemic racisms emerge out of and give rise to environmental degradation; that is, they are often mutually constitutive. The ecointersectional analyses provided throughout the book reveal that ecological indifference and climate injustice are two sides of the same coin. Three distinctive but interrelated domains in which the intersections between systemic racisms and ecological indifference are manifest are identified: (1) differential distribution of harms/benefits due to systemic racisms, (2) racist institutions and practices fueling or causing environmental degradation, and (3) the basic social structures that generate environmental degradation being the same ones that generate systemic oppression of certain groups of people. One of the aims of Racial Climates, Ecological Indifference is to underscore that any effort to protect the environment must also be a fight against systemic racisms and other forms of systemic inequity.

A note on quark and gluon energy-momentum tensors

Abstract: A bstract We discuss the constraints on quark and gluon energy-momentum tensors in QCD that follow from the requirement of Renormalisation-Group invariance of the traces of these operators. Our study covers the most general form of the latter traces, while the energy-momentum tensors themselves are only subjected to very mild constraints. We derive Renormalisation-Group equations for the two finite independent functions of the strong coupling constant and renormalisation scale of minimal subtraction which completely define the energy-momentum tensors. We demonstrate that previously proposed definitions of the renormalized quark and gluon energy-momentum tensors are special cases of our results assuming no explicit dependence on the renormalisation scale. Finally, we present $$ \overline{\textrm{MS}} $$ MS ¯ -renormalised quark and gluon energy-momentum tensors at four-loop order.

Catechol-Functionalized Chitosan Synthesis and Selective Extraction of Germanium (IV) from Acidic Solutions

Abstract: Germanium (Ge) is one of the critical elements that lack an efficient economic recovery process from dilute sources. An improved catechol-based adsorbent, catechol-functionalized chitosan (C–Cat), was synthesized to recover germanium (Ge) from dilute acidic solutions. The adsorbent was also compared with an N-methylglucamine-based commercial adsorbent (Purolite S108) for optimum pH conditions, ion selectivity, adsorption isotherm, adsorption kinetics, and regeneration ability. The newly synthesized C–Cat exhibited higher selectivity against various competing ions than the commercial one (their respective Langmuir capacity was 22.72 and 79.66 mg/g at pH 3) and was more selective for Ge than other adsorbents reported in the literature. Linear free-energy relationships between the distribution coefficients and the metal hydrolysis constants were developed for both C–Cat and S108 at pH 3 and can be used for preliminary prediction of the selectivity of the adsorbents. Adsorptions data followed Langmuir isotherm for both adsorbents, and the kinetics data were well-fitted with pseudo-second-order kinetics. The C–Cat was proven to be completely reusable for multiple cycles after initial re-equilibration.

Heat Transfer and Pressure Loss of Additively Manufactured Internal Cooling Channels With Various Shapes

Abstract: Abstract Additive manufacturing (AM) provides the ability to fabricate highly customized internal cooling passages that are relevant to gas turbine components. This experimental study examines the pressure loss and heat transfer performance of a range of fundamental channel shapes that were produced using direct metal laser sintering. Circular, hexagonal, pentagonal, elliptical, diamond, square, rectangular, trapezoidal, and triangular channel cross sections were investigated. To maintain the same convective surface area between shapes, the wetted perimeters of the channel cross sections were kept constant. Parallel computational fluid dynamic simulations were performed to understand the relationships in cooling performance between several channel shapes. Several characteristic length scales were evaluated to scale the pressure loss and heat transfer measurements. Among the channel shapes investigated, the diamond channel showed the lowest Nusselt number and friction factor. The pentagon exhibited a similar Nusselt number as the circular channel despite having a lower friction factor. There was no difference in scaling the friction factor or Nusselt number results of the different channel shapes between using the square root of cross-sectional area compared to hydraulic diameter as the characteristic length scale

<i>RootSlice</i> —A novel functional‐structural model for root anatomical phenotypes

Abstract: Root anatomy is an important determinant of root metabolic costs, soil exploration, and soil resource capture. Root anatomy varies substantially within and among plant species. RootSlice is a multicellular functional-structural model of root anatomy developed to facilitate the analysis and understanding of root anatomical phenotypes. RootSlice can capture phenotypically accurate root anatomy in three dimensions of different root classes and developmental zones, of both monocotyledonous and dicotyledonous species. Several case studies are presented illustrating the capabilities of the model. For maize nodal roots, the model illustrated the role of vacuole expansion in cell elongation; and confirmed the individual and synergistic role of increasing root cortical aerenchyma and reducing the number of cortical cell files in reducing root metabolic costs. Integration of RootSlice for different root zones as the temporal properties of the nodal roots in the whole-plant and soil model OpenSimRoot/maize enabled the multiscale evaluation of root anatomical phenotypes, highlighting the role of aerenchyma formation in enhancing the utility of cortical cell files for improving plant performance over varying soil nitrogen supply. Such integrative in silico approaches present avenues for exploring the fitness landscape of root anatomical phenotypes.

Sm and Mn co-doped PMN-PT piezoelectric ceramics: Defect engineering strategy to achieve large d33 and high Qm

Abstract: PbTiO3-based piezoelectric ceramics are key materials for developing various electromechanical transducers. For high-power ultrasonic transducers, piezoelectric ceramics are required to possess large piezoelectric coefficient (d33) and high mechanical quality factor (Qm). Although acceptor dopants can improve Qm, they also deteriorate d33. If suitable piezoelectricity-beneficial donor dopants can be introduced into acceptor-doped ceramics, it is very possible to obtain large d33 and high Qm simultaneously in donor and acceptor co-doped ceramics. In this work, a series of x mol% Sm and y mol% Mn co-doped Pb(Mg1/3Nb2/3)O3–30PbTiO3 (PMN-30PT: xSm, yMn) ceramics were prepared by the solid-phase sintered method. The crystal structure, local domain structure and electromechanical properties were systematically analyzed. Optimal performances were obtained in PMN-30PT: 2.5Sm, 1–2Mn ceramics with d33=860–543 pC/N, Qm=495–754, and dielectric loss tanδ=0.0055–0.0086. This high performance originates from the combined effects of (MnTi″−Vo••)× defect dipoles and the local structural heterogeneity.

Probabilistic Integration of Geomechanical and Geostatistical Inferences for Mapping Natural Fracture Networks

Abstract: Abstract Estimation of a reservoir’s production potential, well placement and field development depends largely on accurate modeling of the existing fracture networks. However, there is always significant uncertainty associated with the prediction of spatial location and connectivity of fracture networks due to lack of sufficient data to model them. Therefore, stochastic characterization of these fractured reservoirs becomes necessary.

Regimes of literacy as regimes of truth about Africa: language ideologies and southern voices

Abstract: In this chapter we discuss and problematize the colonial and contemporary connections between regimes of literacy—including ideologies of writing—and regimes of truth about Africa. This means considering the process of knowledge production, dissemination and reception as politically and economically controlled, contributing to a continuous remodeling of power relations. By situating our arguments in African colonial contexts, we explore the role played by ideologies of literacy, mainly centered on the alphabetic script, in defining what counts as language—taken as fixed and named codes-, which consequently shaped the ideological beliefs about the nature of knowledge production and knowledge transmission which is carried out via extant codes. This chapter is on literacy in Africa, colonial regime of literacy, regime of truth, authorship, standpoint, politics of knowledge production, oral tradition, politics of citation and editorial politics. The bigger proposition we are making goes beyond simply identifying insights in Africa; rather, we seek to understand how such insights affected the nature of literacy in the Global Norths as well.

User engagement with a popular food brand before, during and after a multi-day interactive marketing campaign on a popular live streaming platform

Abstract: To assess viewer engagement of a food advertising campaign on the live streaming platform Twitch.tv, a social media platform that allows creators to live stream content and communicate with their audience in real time.Observational analysis of chat comments across the Twitch platform containing the word 'Wendy's' or 'Wendys' during a 5-day ad campaign compared with two 5-day non-campaign time periods. Comments were categorised as positive, negative or neutral in how their sentiment pertained to the brand Wendy's.Twitch chatrooms.None.There were significantly more chatroom messages related to the Wendy's brand during the campaign period. When considering all messages, the proportion of messages was statistically different (x2 = 1417·41, P < 0·001) across time periods, with a higher proportion of neutral and positive messages and a lower proportion of negative messages during the campaign compared with the comparison periods. Additionally, the proportion of negative messages following the campaign was lower than before the campaign. When considering only positive and negative messages, the proportion of messages was statistically different (x2 = 366·38, P < 0·001) across each time period with a higher proportion of positive messages and a lower proportion of negative messages during the campaign when compared with the other time periods. Additionally, there was a higher proportion of positive messages and a lower portion of negative messages following the campaign when compared with before the campaign.This study demonstrates the impact and sustained impact of a fast-food brand ad campaign on brand engagement on the live streaming platform Twitch.

Time-resolved passive cavitation mapping using the transient angular spectrum approach

Abstract: Passive cavitation mapping (PCM), which generates images using bubble acoustic emission signals, has been increasingly used for monitoring and guiding focused ultrasound surgery. This study investigates a transient angular spectrum (AS) approach for PCM. The working principle of this approach is to backpropagate the received signal to the domain of interest and reconstruct the spatial–temporal wavefield encoded with the bubble location and collapse time. The transient AS approach is validated using an in silico model, water bath, and in vivo experiments. It is found that the transient AS approach yields similar results to delay and sum, but is considerably faster. The results obtained by this study suggest that the transient AS approach is promising for fast and accurate PCM.