DSpace@RPI (Rensselaer Polytechnic Institute)
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Effects of sounds on the visitors’ experience in museums
No full textAugust 2023School of ArchitectureWith the growing popularity of museums, there is an increasing awareness of the importance of acoustics in creating a high-quality visitor experience. As a result, the research field of museum acoustics has gained attention, particularly regarding objective/physical parameters. However, there is also a need for studies on user perception and experience. Furthermore, innovative solutions are required to improve acoustic conditions without complex treatments that might compromise the exhibitions. Sound masking, a proven and widely used technique, is commonly employed to enhance the acoustic experience in various environments by rendering target speech unintelligible, reducing annoyance, and improving listeners' perception. Conventional masking systems typically utilize random steady-state electronic signals adjusted to specific environments. This study investigates the effect of conventional sound maskers and sounds congruent with the museum exhibition context on visitors' experience. This proposal is based on research demonstrating that context significantly influences a soundscape's positive experience and the perception of the museum environment. Therefore, this study hypothesizes that sounds congruent with the environment are equally effective as the conventional masking sound in distracting background noise, enhancing visitors' experience and engagement with the artwork and creating a more comprehensive and immersive experience.M
Design and control of a nonprehensile impulse manipulator
No full textMay2023School of EngineeringIn modern manufacturing industries, small components such as bolts and nuts of a complex assembly are usually delivered to the plant in big loose batches. To autonomously feed those components into ongoing assembly processes with celerity, vibratory bowl feeders (VBF) were developed in 1950 to perform singulation, orientation, and manipulation tasks. In the past 20 years, however, as robot assembly systems became a prominent part of the new and more versatile manufacturing environment, VBFs appeared to be less suitable as 1) each of them is designed for one specific part only, and 2) the cost to design and tune a new variation is expensive. This thesis proposes an alternative design of a nonprehensile impulse manipulator with the corresponding control method for singulation, orientation, and manipulation by means of seven fixed-position variable-energy solenoid impulse actuators located beneath a semi-rigid part supporting surface. To supervise the manipulator, a 640p webcam with computer vision tools was included to provide part pose information. To control the device, machine learning algorithms were used to generate a part-specific control policy that bring the part to a user specified target pose.
The device was tested by manipulating a six-faced craps-style die and an imprecise flat square wooden nut from a child's assembly toy. Compared with the benchmark policy, the trained optimal policy was able to flip the die to any desired face with six times higher probabilities and stand the flat nut up on its less stable pose with two times higher probabilities. The device was then put into a collaboration task with a 6-DoF robot manipulator to complete a manipulation task on the six-faced die. The resulted average execution time was faster than most state-of-the-art manipulation tactics.M
Gender dysphoria and being human
No full textMay 2023School of Humanities, Arts, and Social SciencesScientific practices and the Diagnostic and Statistical Manual (DSM), now in its 5th version, produced by the American Psychological Association (APA), have been some of the strongest powers confining gender dysphoria to a mental disorder. The ways that science has pursued and justified sex differences has been heavily influenced by politics, neglecting other natural forms of sexual identification. The scientific systems that justify the need for a gender binary are the same systems that made it possible for the DSM-5 to confine gender dysphoria, both in its definitions and diagnoses processes, to a mental disorder. The irreconcilable amount of power that the DSM and science has, has inadvertently built walls around our own gender identities, keeping us in a dysphoric state. This thesis serves to expand on the definition of gender dysphoria within the DSM, as an effort to encourage our acceptance of gender dysphoria within our own lives. Through an application of thought practices from Judith Butler, Walter Mignolo, Anne Fausto-Sterling, Catherine Walsh, Londa Schiebienger, Wendy Brown, Frantz Fanon, and Julian Go, this thesis reconsiders the ways in which both scientific practices and the DSM have defined our gender identities. In doing so, fissures are created that allow for us to peer beyond a world with oppressive gender dichotomies, in order to reconcile with the ways we have been forced into feelings of gender dysphoria, and the ways that gender dysphoria can be reframed as a liberating inevitable experience.M
Infomorphism: an urban planning framework for local renewable energy integration
No full textAugust 2022School of ArchitectureWhat a future city could be and why has always created discourse within the discipline of architecture. The form of a city constantly evolves through policy and regulation changes, which are affected by social, economic, technological, and environmental forces. The negotiation of these forces has always provoked explorations in envisioning the future state of a city. Today, energy consumption is becoming of primary importance when considering city planning processes. Because of rapid population growth and global climate catastrophes, improving urban energy efficiency has forced computational designers and planners to address the broader impacts that renewable energy systems can have on the form and function of cities. At the same time, Centralized energy grids are no longer the only base for a city to grow. They have become an object of design. Urban planners and engineers are designing new tools that address how renewable energy integration can inform the evolution of cities. This thesis introduces a computational planning framework for addressing renewable energy integration problems using system optimization approaches and reinforcement learning algorithms that generate urban collective forms with optimal local energy exchange networks. More specifically, the concept of Zero Energy Buildings (ZEBs) is a response to the question of how to improve renewable energy integration at the building level. ZEBs are energy-optimized buildings. They capture, store, and exchange locally available renewable energy through the use of integrated, energy metabolizing building technologies. When considering ZEB buildings as an urban network, a fundamental ``right to renewable energy access" must be introduced into planning processes. Just as urban planning today ensures that buildings have access to fresh air, sunlight, or water through policies, regulations, and building codes, ZEBs - as renewable energy-dependent buildings - now need access to local solar, wind, or geothermal energy equitably. It is my conjecture for the development of this body of work that we need to acknowledge that the sun, wind, or heat from the earth belongs to everyone and, as such, develop urban planning processes that grant equitable access to these newly accessible, basic, and free resources. Many different modeling efforts and software platforms have been designed to address energy efficiency issues related to ZEBs. For example, generative design frameworks and Urban Building Energy Modeling (UBEM) tools integrated with joint simulations have been developed to evaluate the energy performance of ZEBs through multi-objective optimizations and data analytics. However, these tools do not have renewable energy rights as drivers for a city’s form, function, and infrastructure. The developed computational planning framework, titled Infomorphism, augments a generative planning process with Artificial Intelligence (AI)-based energy-sharing network optimization models to explore potential planning policies associated with renewable energy rights. Taking renewable energy accessibility as a driver for optimizing planning envelopes, Infomorphism as an AI-based framework helps optimize energy absorption for a city as a whole and balances energy exchange between areas of supply and areas of demand. Several case studies for Manhattan have been conducted to provide alternative planning environments for validating the effectiveness of the proposed workflow. The case studies show how a city can be developed as an energy network that ensures equitable access to renewable energy (in the form of heat and electricity) absorbed from the planning envelopes with minimum levelized energy costs. The results from the case study show how geothermal and solar drive a future city's collective form and infrastructure to achieve up to 79% local renewable energy integration (37.9% from solar energy and 41.1% from geothermal heat pumps at designated locations) with a total levelized energy cost of $3.55 * 10^7. Establishing new policies and regulations according to equitable energy rights associated with renewable energy integration can collectively drive a city's form, function, and infrastructure and discuss energy policies emerging from this research. It is anticipated that the development of Infomorphism will support the decision-making process related to architectural design, urban planning, energy infrastructure design, and renewable energy integration at both building and urban scales.Ph
Towards built ecologies: a consideration of multi-systemic bioresponsive behaviors within architectural systems
No full textDecember 2018School of ArchitectureThe Built Environment shapes our lived experience both as a subjective measure of personal experience, and as an objective measure of biological interactions catalyzed within an environment. An individual’s sense of well-being, their physiological and psychological health, is as mutually reinforced by the systemic response of their physical constitution in an environment, as it is a personalized interactional response of themselves within their environmental world-view. The research addresses the need to comprehend the holistic influence of built environments on the human body and mind, responding to increased patterns of urban living and the reliance that the individual and the social collective places on these as lifelong habitats. Within this context, population-level epidemiological studies that focus on the welfare of urban dwellers have shown an increased risk of non-communicable diseases associated with various aspects of urban lifestyles, such as stress and pollutant exposures. A bi-directionality of correlational data across factors has similarly been shown, wherein lifestyle and/or mental outlook mutually reinforce the risk of disease (i.e. reinforces the likelihood of diseases OR reinforces the risk of disease) or the reverse, whereby disease reinforces particular impediments to livelihood, such as an increased probability of depression and antisocial lifestyle changes. These areas of research form part of numerous initiatives which initiatives, which are collaboratively attempting to work across disciplines, ones which take a Salutogenic approach towards interpreting the multifactorial influences on our sense of well-being, and of the value in collaboratively partaking from all professional standpoints. The research is lensed within the scope of architectural design and interdisciplinary sciences, a field which draws on historic and contemporary theoretical discourse within the humanities, alongside that of the paralleled evolutions in the sciences and applied technology. Primacy is placed on the human body, both for the satisfaction of personalized embodied experience as a humanist interest and as an instrument to measure collective health outcomes. The experiential has long formed part of architectural discourse, attempting to derive qualities from the subjective understanding of the body in a space, as the instrumentation of perception and as the basis by which we cognitively derive meaning. In providing a starting point, the Phenomenological theory of Husserl and Merleau-Ponty is introduced, relevant to the modern paradigm preferencing the experience of the individual over the cultural collective. Traversing the theoretical to that which is critically applied to society, Heidegger and Latour inform this distinction then are given to examining the natural and unnatural as outcomes of humankind’s making; the technological products of the alienated (dis)embodiment of their makers, impacting qualities of the built environment. Conceived of as multi-systemic bioresponsive considerations, firstly necessitates characterizing the human individual as a system through which bioresponsive qualities can be considered and mapped qualitatively or measured quantitatively, and secondly, considerations towards multiple systems being engaged in a set of changing interrelated relationships, the human system being one of these. A relationship is thirdly suggested between these multiple systems and the environment, the latter’s behaviors and characteristics similarly interrelated to that of the systems that are present. The environment as a physical and immediate setting, is viewed as a dynamic continuum of stimuli, both rhythmic and varying, engaged with, and described as, natural phenomena that is aligned with the biophysical understanding of these phenomena, which interact with the body’s nervous system as sense perception over time. These factors are shown to be of both a physically and cognitively perceived nature, with continued debate on the primacy of one over the other, be that affective or cognitive primacy. Relevant to the creative anthropocentric act of making one’s own environment to suit the ideological and physical needs of oneself and one’s community, this is thus argued as of special interest to both architectural theory and building practice. The discussion will focus on the built environment’s capacity and willful objective to create indoor conditions which are ecologically inclusive by nature, as a means of meeting the needs of the (multi-systemic) occupancy it is designed for. Further to this, as a use case, the research will focus on an multi-systemic experimental inquiry into the effects of air quality constituents on human health and wellbeing. Their transfer and deposition has increasingly been shown as impactful at all scales of human and ecological health, suggesting the interdependency of inclusivity as well as the risks associated with the opposite - alienation. Particular focus is placed on a growing area of concern, that of Indoor Air Quality (IAQ). Numerous studies have shown a direct causal relationship with certain aspects of poor air quality, which are linked to reduced cognitive function, to immune and long-term health. For these reasons, addressing IAQ is a relevant use case to this research as it provides both a medium across which to gauge the interactions between the human body and environment, as well as a quantifiable description of what airborne properties, to what specific degree, influence the human body. It provides a strong point of departure for a research thesis which might otherwise be side-lined to theoretical or hypothetical system’s concepts. The full breadth of this is addressed in detail through the Case Study which looks comparatively at the Air Quality of several environments and the quantified impacts these have on the human occupants.M
DeFi Survival Analysis: Insights into Risks and User Behaviors
No full textWe propose a decentralized finance (DeFi) survival analysis approach for discovering and characterizing user behavior and risks in lending protocols. We demonstrate how to gather and prepare DeFi transaction data for survival analysis. We demonstrate our approach using transactions in AAVE, one of the largest lending protocols. We develop a DeFi survival analysis pipeline which first prepares transaction data for survival analysis through the selection of different index events (or transactions) and associated outcome events. Then we apply survival analysis statistical and visualization methods such as median survival times, Kaplan–Meier survival curves, and Cox hazard regression to gain insights into usage patterns and risks within the protocol. We show how by varying the index and outcome events, we can utilize DeFi survival analysis to answer three different questions. What do users do after a deposit? How long until borrows are first repaid or liquidated? How does coin type influence liquidation risk? The proposed DeFi survival analysis can easily be generalized to other DeFi lending protocols. By defining appropriate index and outcome events, DeFi survival analysis can be applied to any cryptocurrency protocol with transactions
A design framework for the integration of interscalar flow control systems in architecture
No full textAugust 2017School of ArchitectureCurrent environmental control systems (ECS) innovations in the built environment are predominantly developed within a fossil fuel systems paradigm characterized by technical and disciplinary boundaries that restrict system performance to short-term quantitative metrics. The conventional interface between controlled interior environments and exterior fluid flow is governed by centralized combustion-based machine logics that are no longer concurrent with interdisciplinary understanding of fluidic environmental relationships, and which furthermore contribute substantially to greenhouse gas emissions and the effects of waste heat in cities. With global urbanization trends rising, the centralized combustion paradigm behind conventional systems is ill-equipped to effectively address international and local climate change initiatives for buildings, or to meet increasing demand for high-resolution environmental performance. As emerging interdisciplinary research in Architecture, Engineering, and Construction (AEC) characterizes the critical relationships between interscalar urban aerodynamic phenomena and environmental outcomes, novel design frameworks are needed that address fluidic behaviors and aerodynamic performance at multiple system scales and interfaces. Originating from within aeronautical engineering design, aerodynamic flow control systems modify certain characteristics of the surrounding fluidic environment to achieve desired performance outcomes. Developments in aerodynamic flow control systems present a technology transfer opportunity for AEC research to actively engage fluid flow as both a bioclimatic design driver and an extension of the building envelope, or mediator between exterior climate and interior conditioned space. The aim of this research is to develop a design approach to adapt fluid flow control techniques from the aeronautical engineering context to the interscalar environmental interfaces of urban buildings. Integration of flow control into architectural systems offers an adaptable technical design pathway towards controlling the aerodynamic behaviors that drive environmental design outcomes. This inquiry addressed the aerodynamic performance through system design and testing at key interfaces of energy exchange throughout the building. First, the building exterior and surrounding region, where wind plays a driving role in building energy and the quality of indoor environments, was studied. Through the development of an interscalar design framework, the exterior flow control technique was then adapted to interior air delivery for augmentation of ventilation strategies and parametric study of a modular airflow approach. Through negotiation of design space parameters at each interface of testing, iteratively-developed performance metrics were brought together in the scope of this work as part of a synthetic design integration approach. By considering fluid flow as an environmental continuum of interactions through multiple building scales, this research seeks to facilitate re-engagement of environmental controls design, conventionally relegated to the purview of mechanical engineering, with the aesthetic, material, and haptic tenets of architecture. Enacting and building upon multi-faceted design performance criteria may spur the emergence of new ECS strategies, while offering the potential to augment existing alternatives to conventional systems. Finally, through articulated performance design interfaces brought about by deployment of the design approach, the invisible fluidic interrelationships within the built environment can be rendered visible and clearly characterized along a diverse morphological taxonomy. As such, these relationships may acquire a new phenomenological role and agency within the technical and political discourse on architectural systems.Ph
Biophysical investigation for elucidating complex chromatographic behavior in downstream processing of biologics
No full textMay 2018School of EngineeringMonoclonal antibodies (mAbs) have emerged as highly important protein therapeutics in the recent years. In spite of targeting a wide array of targets, mAbs have a conserved amino acid sequence and structure and share a high degree of similarity in biophysical properties, which facilitates development of a platform process for antibody manufacturing. Chinese Hamster Ovary (CHO) cells are the most commonly used expression systems to produce mAbs due to their ability to express antibodies with human-compatible glycosylation patterns. One of the challenges with these expression systems is the over-expression of a large number of host cell proteins (HCPs) that are released into the cell culture fluid during processing along with the mAb product. Removal of these HCPs from the antibody feedstocks, particularly those that are associated with the mAb product, is a major impediment in establishing robust platforms for two-column downstream bioprocesses. A fundamental understanding of the impurities and their interactions with the product would help in designing efficient separation process. The aim of this study was to delve into the nature of mAb-HCP complex formation and obtain mechanistic insights using a combination of biophysical techniques and computational tools, and to understand the impact of various process variables on the strength of these interactions. The first part of the work involved identification of model proteins that interact with the mAb using cross interaction chromatography. The proteins that demonstrated highest strength of interaction were then utilized to explore the mAb-model protein interactions in more detail using fluorescence polarization. Binding studies under varying salt concentrations provided insights into the driving force of these interactions. The energetics of interactions as well as enthalpic and entropic contributions to the binding were obtained by employing fluorescence polarization at different temperatures. Computational tools like protein-protein docking and protein surface property maps further aided in identifying residues or clusters on the protein surface that are important for these interactions. The insights obtained from this study were then applied to an industrially relevant host cell protein that has been identified to be challenging to remove, Cathepsin D, to identify potential mechanism of interaction with different mAbs. Surface plasmon resonance was employed to obtain the kinetics of these interactions under a range of fluid phase conditions with varying salt concentrations and pH, and it was observed that higher pH had a significant effect on mitigating these interactions. The data obtained from SPR experiments was used to evaluate the effectiveness of the wash conditions in disrupting mAb-Cathepsin D interactions using protein A chromatography and Cathepsin D enzymatic activity assay. Protein surface property maps and protein-protein docking calculations were then used to elucidate the mechanism of interaction by identifying potential residues or clusters of residues involved in the binding. The sites of interaction on the mAb surface and Cathepsin D were also identified using covalent crosslinking coupled with mass spectrometry, and the importance of the CDR regions in mediating these interactions was established. Importantly, a strong agreement was shown between experimental and simulation data. This work establishes various experimental and computational approaches for studying mAb-host cell protein interactions that are encountered in downstream bioprocessing of monoclonal antibodies, which would be applied in the future to create predictive tools for mAb-host cell protein interactions to improve the bio-separation processes.Ph
Natural polymers and alternative drug delivery systems
No full textAugust 2023School of ScienceNatural polymers are promising candidates for biomedical applications such as wound healing and drug delivery. For the latter, oral administration is preferred since it’s non-invasive, and is convenient to patients improving compliance. In this thesis we describe an oral delivery system for heparin that exploits the formation of an ionic complex that is pH sensitive. In addition, natural polymers can be processed into matrices that are effective wound healing agents. Herein, we describe the development of bacterial cellulose matrices with varied morphologies that control the rate of drug diffusion to the wound site. Ionically Complexed Nanoparticles for Heparin Oral DeliveryIonically complexed nanoparticles were prepared from an anionic polysaccharide drug, heparin, entrapped by a positively charged chitosan polysaccharide. In this study, the encapsulation of heparin was studied to optimize the properties needed for its oral drug delivery. Chitosan, used in various biomedical applications, was selected as a cationic polymer for heparin encapsulation. These particles were prepared with a slightly positive charge and an appropriate size for oral drug delivery. In addition, the release profiles of these ionically complexed nanoparticles were improved by using FDA-approved stabilizers, such as pluronic non-ionic surfactant and polyvinyl alcohol. These results obtained in vitro suggest that these stabilized, ionically complexed nanoparticles may be well-suited for the oral drug delivery of heparin into the gastrointestinal tract. Drug Diffusion Through the Bacterial Cellulose Membrane with Varied MorphologyBacterial cellulose (BC) is a naturally derived polymer from the bacterium G. xylinus. BC has high mechanical strength, water holding capacity, and biocompatibility such that it is a useful matrix for drugs that can diffuse at controlled rates to wound sites such as burns. A critical challenge is to develop methods that lead to BC matrices with controlled morphological parameters such as nanofiber orientation and lamellar structure. Gelatin proved to have a strong effect on these organization parameters. The fraction of BC with lamellar and random nanofiber order as a function of gelatin added to BC forming cultures was characterized. Multiple scanning electron microscope images were recorded and analyzed to estimate the lamellar content throughout the matrix. The important learning is that BC morphology is a critical parameter controlling drug diffusion such that it is continuous or leads to blocking of diffusion pathways such that ceasing further diffusion of drug.Ph
Optoelectronic properties of low-dimensional ruddlesden-popper and sillÉn-aurivillius perovskites
No full textAugust 2020School of EngineeringThe versatile corner-sharing octahedral structure and highly tunable chemistry of perovskite-structured crystals endow them a plethora of physical properties. In this work the epitaxy and optoelectronics properties of three optoelectronic perovskites, CH3NH3PbI3, 2D Ruddlesden-Popper phase (C4H9NH3)2PbI4 and quasi-2D Sillén-Aurivillius phase Bi4NbO8Cl, are investigated. Ambiguities on the carrier recombination lifetime of CH3NH3PbI3 were revolved by time-resolved photoluminescence spectroscopy of CH3NH3PbI3 single crystals. It was found that the carrier decay profile yielded two components, the faster component turned out insensitive to excitation intensity and was attributed to the radiative recombination near surface that was dominated by defect-assisted non-radiative processes, while the slower component was inversely proportional to excitation intensity and was attributed to recombination in the bulk. The first van der Waals epitaxy in 2D halide perovskite was developed in Ruddlesden–Popper phase (C4H9NH3)2PbI4 on Si (001) or muscovite mica using cold-wall CVD. Using the single-crystalline epitaxial flakes with lateral size 5~30 μm and thickness 20~200 nm, it was demonstrated that the weak van der Waals interaction from epitaxy and within the crystal can counter-intuitively influence the structural phase transition and electron-phonon coupling. Using temperature-dependent photoluminescence spectroscopy, the remote phononic effect from van der Waals force from substrate was found to reduce structural phase transition temperature by over 150 K, with flake thickness reducing below 100 nm the strength of electron-phonon coupling via Fröhlich interaction was found to reduce by up to 30%. Both discoveries indicate that the conventional understanding on the localized and weak nature of van der Waals forces must be adjusted. The electric-field non-volatile control over spin texture was demonstrated for the first time using ferroelectric Sillén-Aurivillius phase Bi4NbO8Cl. The electric-field control of spin degree of freedom has wide applications in spintronics. The state-of-the-art magnetoelectric technologies mainly relies on multiferroic heterostructures or current-driven spin-charge inter-conversion that are somewhat limited by the volatility, complexity in device fabrication or the high energy consumption of current-based operation. In principle, the spin structure of strong spin-orbital-coupling ferroelectrics is locked with electric dipole ordering and can be switched by switching the ferroelectric orientation (Rashba-Dresselhaus effect). Due to the scarcity of strong spin-orbital-coupling and low-in-defect materials, the experimental demonstration of this concept has so far remained elusive. Using single crystalline Bi4NbO8Cl nanosheets with lateral size 10~30 μm and thickness 100~300 nm and resorting to circular photogalvanic effect, it was found that the response to left/right circularly polarized light was created, erased and recreated by electric poling or sweeping, indicating a direct correlation between ferroelectric orientation and spin selectivity (valley-photon locking). The first demonstration of ferroelectric-field control over spin texture and valley-photon interaction in Bi4NbO8Cl provides a new solution to non-volatile low-power-consumption opto-spintronics.Ph