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Microstructural Controls on the Macroscopic Behavior of Analogue Rocks (Geo-Architected Rocks)
No full textProbing the subsurface for evidence related to the degradation of porous mediums and the evolution of damage mechanisms has been a long-standing challenge in geophysics. As such imaging and predicting fracture network development has remained a difficult area for subsurface science for decades despite the seminal and significant works put forward by many researchers. While this has provide great understanding about the behaviours and properties of natural porous media, there is still much that needs to be explored particularly in regard to the mineralogical composition and chemistry of clay-rich rocks. Despite the fact that argillaceous rocks which consist of different types of clays and varied mineral composition are ubiquitous in nature and are often the target of several technologies (e.g. geotechnical engineering, nuclear waste storage and disposal,hydrocarbon exploration and extraction, carbon capture and sequestration, etc.), many studies focus primarily on the bulk properties or the percentage of components in the matrix. For these reason and due to the problems that can be encountered with natural rocks that contain a swelling clay component whether randomly distirbuted or localized in consolidated globs in zones of the matrix, the influence of clay chemistry in relation to fracture development which is not well characterized, especially during desaturation is investigated with analogue rock samples which were systematically fabricated for this purpose.The research performed in this dissertation investigated, the applicability of the fabrication protocol for developing synthetic rocks with desirable rock like features and behavior, the impact and relationship between the rock properties, the microstructural composition, water loss, and the macroscopic behavior of the analogue rocks, focusing on the structure and chemistry of the constituent clay materials. Synthetic rocks were fashioned with the necessary geometries, properties, and material compositions. On the macroscopic scale the fracture and drying behavior of the synthetic rocks were examined with 3D X-ray microscopy and further evaluated through the utility of acoustic emission monitoring, water loss monitoring, and unconfined compressive testing. On the finer scale (nano-microscale), the chemical and mechanical properties, and behavior of select clays was explored by exploiting several methods of material characterization which also included cation exchange experiments coupled with inductively coupled plasma optical emission spectrometry (ICP-OES).For the finer scale, experiments verified that calcined kaolinite clay had a different mineral structure and negligible to non-existence shrinkage abilities. In contrast, the montmorillonite clays possessed higher and similar moisture contents but, owing to the different principal cations these clays interacted a bit differently in the highly akaline environment, experienced varying degrees of shrinkage, and had observedly minor structural dissimilarities. For the relatively larger scale, the emergence of damage, extent of the damage network, and the patterns of the crack network mainly depended on the microstructural composition of the analogue rocks, particularly it’s clay chemistry and/ or distribution. The location of damage depended on the emplacement and percentage of swelling clay in the matrix, and numerical investigations with peridynamics revealed that the observed damage was a consequence of the action of the swelling and non-swelling components of the matrix
Development of an Open-Source Toolbox for Design and Analysis of Active Debris Remediation Architectures
No full textOrbital Debris is a growing challenge for the Space Industry. The increasing density of derelict objects in high-value orbital regimes is resulting in more conjunction warnings and break-up events with cascading repercussions on active satellites and spacecraft. The recent rapid growth of the commercial space industry, in particular proliferated satellite constellations, has placed orbital debris remediation at the forefront of Space Industry efforts.The need to remove existing debris, combined with a growing demand for active satellite life extension services, has created an emerging market for space logistics, in particular spacecraft capable of rendezvous and docking, orbital refueling, debris deorbiting, or object relocation. This market has seen numerous companies emerge with multi-purpose on-orbit servicing platforms. This ecosystem poses technological, economical, and policy questions to decision-makers looking to acquire platforms or invest in technologies and requires a System-of-Systems approach to determine mission and system concepts of merit.An open-source modeling, analysis, and simulation software toolbox has been developed which enables rapid early-stage analysis and design of diverse fleets of on-orbit servicing platforms, with a specific emphasis on active debris removal applications. The toolbox provides fetching and processing of real-time orbital catalog data, clustering and scoring of high-value debris targets, flexible and efficient multi-vehicle multi-objective time-varying routing optimization, and fleet-level lifecycle cost estimation. The toolbox is applied to a diverse sample of promising commercial platforms to enable government decision-makers to make sound investment and acquisition decisions to support the development of ADR technologies, missions, and companies
Towards Carbon-Aware Spatial Computing: Challenges and Opportunities
Get PDFCarbon-aware spatial computing (CASC) is focused on reducing the carbon footprint of spatial computing itself and leveraging spatial computing techniques to minimize carbon emissions in other domains. The significance of CASC lies in its potential to mitigate anthropogenic climate change by offering numerous societal applications, such as carbon-aware supply chain development and carbon-aware site selection. CASC is challenging because of the spatiotemporal variability and the high dimensionality of carbon emissions data, involving spatial coordinates and timestamps. Related work, known as carbon-aware computing, mostly focuses on job scheduling of cloud computing, and there is a lack of surveys and review papers detailing the potential of CASC on variant domains and applications. In this paper, we provide the vision of CASC by proposing a taxonomy of sub-domains within CASC and introducing ideas beyond job scheduling, such as carbon-smart site selection. We also briefly review the literature in selected sub-domains and highlight research challenges and opportunities. Given the societal importance of the topic, we encourage the scientific community to use this brief survey to expand the field of study into other related sub-domains and advance CASC more broadly
Complex Impacts of Wars on Global Sustainable Development in a Metacoupled World
Get PDFWars and armed conflicts have had profound impacts on local and global sustainable development in an interconnected world. However, evidence on the impacts of wars is fragmented and little attention has been paid to the impacts on the 17 UN’s Sustainable Development Goals (SDGs), a unifying framework for achieving global sustainable development. This perspective synthesizes the scattered information to provide a holistic analysis and highlight the applications of remote sensing in assessing the impacts of wars on global sustainable development in a metacoupling world. Wars have complex impacts on all 17 SDGs, which cascade beyond conflict zones and spillover to adjacent and distant countries worldwide. Satellite remote sensing can play a significant role in monitoring environmental and socioeconomic impacts such as crop production, deforestation, pollution, urban damage, and migration. Remote sensing can provide timely, spatiotemporal, large-scale data for sustainable development impact assessment of conflict zones with restricted access. As 2023 is the middle point of the time period (2015-2030) for the 2030 Agenda for Sustainable Development, it is urgent to conduct more quantitative assessments for wars around the world such as the Russia-Ukraine war. Enhancing remote sensing applications in war-related impact assessment with advanced models and frameworks is very helpful and significant. It is also critical to rethink about global governance by incorporating the ripple effects of wars for policy adjustments to achieve SDGs by 2030
Market-Mediated Effects: What Are they? And why are They Important for Geospatial Analysis of Sustainability Policies
Get PDFMarket-mediated effects can mitigate or amplify the intended effects of sustainability policies. They can also have unintended consequences, including inducing new sustainability stresses or threatening food security. It is important to understand these effects when designing sustainability policies. This paper provides prominent examples of market-mediated effects of a variety of sustainability policies in the food, energy, land and water nexus. This paper reviews the empirical evidence on market-mediated impacts of economic policies generally and then provides a review of recent geospatial modeling aimed at capturing these impacts in the context of local and regional land and water sustainability policies. The paper also discusses the challenges of designing sustainability policies that are effective in the face of market-mediated effects
2023 Cantaloupe Cultivar Evaluation in Indiana
Get PDFTraditionally, eastern-type cantaloupe is produced in Indiana. Longer shelf-life cultivars were developed and have been grown in Indiana. This report includes 11 cantaloupe cultivars, including some newly developed ones
Modeling of a Flexible Perforated Membrane Backed by Granular Materials
Get PDFIt has recently been shown that adding activated carbon particles to the interior of a Helmholtz resonator can improve the resonator’s absorption at low frequencies. A similar improvement has been found when a layer of activated carbon partially fills the space behind a finite, tensioned impermeable membrane. In that case, absorption peaks due to the modal response of the tensioned membrane were found to be significantly enhanced in the low frequency range. In the present work, the modeling aspects of the latter work are extended in a number of ways. First, the circular membrane is considered to be both tensioned and flexurally stiff, and further, it is micro-perforated: i.e., it has a finite flow resistance. Secondly, the particle layer behind the membrane is modeled by using a finite difference procedure that accounts for interaction of the particle layer and walls that contain it: i.e., the particle stack itself is allowed to exhibit modal behavior in the radial direction. Finally, the interaction of the membrane nearfield and the particle stack is fully accounted for. It is shown that previously observed behavior can be reproduced, and further that the modal behavior of the particle stack may also enhance the system’s absorption
A general effectiveness-NTU modeling framework for membrane dehumidification systems
No full textSelective membrane dehumidification is a promising technology for energy efficient air dehumidification in buildings and has been ranked as a top alternative technology by the Department of Energy. One critical area that needs to be addressed is system modeling that incorporates device mass transfer characteristics and sizing. This work develops, validates, and applies a simple effectiveness-number of transfer units (−TU) modeling framework for dehumidification technologies that can be used to predict performance and determine required membrane area for a wide range of technologies, including energy recovery ventilators, vacuum membrane dehumidification, and desiccant dehumidifiers. Although the −TU method is a well-established framework for sizing and modeling heat exchangers, past attempts to create L − T L (meaning −TU for latent loads) models for dehumidification (referred to as latent cooling): (1) don’t agree on the definition of T L, (2) are not fully analogous to the heat transfer definition of TU, (3) cannot be easily applied across all technologies, (4) use humidity ratio, not vapor pressure, as the driving force, and (5) are often complex or lack a fundamental basis. In this work, we develop an effectiveness-NTU model for membrane humidity exchangers that is based on vapor pressure differences, employs a novel definition of the latent number of transfer units for dehumidification applications (T L) and is fully analogous to the heat transfer effectiveness-NTU models employed for sensible heat exchangers. The resulting L−T L relationships are validated against experimental data with a maximum error of 1.2%. The overall methodology is applied in case studies for vacuum membrane dehumidification system sizing showing that the ratio of required membrane area per building floor area ranges between 0.1 to 3.5 depending on the building type and operating conditions. Finally, the framework is further generalized for applicability to any gas separation application
Connecting with the Outside World: Psychosocially Supportive Aspects of Operational Communication Between Isolated Crews in Space and Mission Control on the Ground
Get PDFRadio-based communication between crew members in space and mission control centers on the ground has the operational purpose of supporting the safe and effective execution of missions in space. Space-to-ground communication also, however, constitutes one of the relatively few interpersonal relationships astronauts have during missions and in addition to its operational purpose, this communication can support astronauts’ wellbeing. The purpose of this paper is to identify psychosocially supportive aspects of operational space-to-ground communication between astronauts in space and spacecraft communicators on the ground. Through qualitative analysis of authentic mission communication, this paper identifies two supportive aspects and develops a terminology for describing these. Operational kindness describes operational messages that are considerate, show understanding of others, and include implicitly expressed enjoyment of associating with others. Operational wit describes operational messages in which not only content and clarity, but also the style with which a message is conveyed is given attention, by including a subtle wit or charm. Both are illustrated with excerpts from data and are discussed in relation to existing research
Hmong Narratives as Testimony
Get PDFRefugees are often depicted in studies and popular media as helpless and in need of rescuing. In the song “Hmoob Zaj,” which was released on YouTube in 2019, Hmong rapper Shong Lee humanizes Hmong refugee experiences by sharing a story that has been “secreted” (M. Vang, 2021, p. 10) by the U.S. government. Through the public archiving of this story on YouTube, Lee presents what Espiritu (2014) calls an “oppositional narrative” (p. 163) that speaks back to the empire. He asserts a critical stance to challenge the dominant narrative, validate the experiential knowledge of Hmong people, contribute to Hmong collective remembering, and co-construct a Hmong diasporic collectivity that looks to the future without forgetting the past. Specifically, “Hmoob Zaj” is a testimony that reveals U.S. injustices in Southeast Asia and positions Hmong people as legitimate producers of knowledge not confined to the boundaries of Western ideals. This type of knowledge is essential to transforming the schooling process by (a) providing an inclusive, humanizing, and just understanding of Hmong history and (b) revealing the way dominant perspectives and ideals distort Hmong realities in order to uphold existing power relations