275 research outputs found
Influence of Electrode Formulation in Silicon Microparticle Electrodes for Lithium-Ion Batteries
No full textCommercialization of silicon anodes could be a critical step towards increasing electric vehicle adoption among consumers. Silicon has the potential for three times the volumetric capacity, ten times the gravimetric capacity, are more amenable for fast-charge, and can be made using similar manufacturing processes as the incumbent, widely commercialized graphite anodes. To achieve such high capacities, silicon forms amorphous alloys with lithium during lithiation. To accommodate the alloying lithium, the silicon will expand up to three times its original volume, kicking off a cycle of degradation involving particle cracking and irreversible solid electrolyte interphase growth. Although nanosizing or nano-structuring can circumvent this degradation pathway, nanomaterials are not suitable for near-term commercialization due to high material cost and safety concerns. Therefore, to meet battery cell cost targets of $75/kWh, development efforts have shifted towards improvement of microparticle silicon electrodes.
Many milestones in the development of silicon anodes were enabled by breakthroughs in electrode formulation. The most prominent of these have been the advancements in binder chemistry and conductive additive integration. Comparatively few studies are devoted to understanding the influence of electrode formulation – the relative ratios of electrode components – on electrode properties and performance.
This thesis examines the influence of formulation on structure-properties-performance relationships in silicon microparticle electrodes for lithium-ion batteries. We track how formulation affects porosity, mechanical properties, and electrical conductivity, and identify correlations between these characteristics and electrochemical performance. Full cells with industrially relevant capacity loadings (4.5 mAh cm-2 at beginning of life) were evaluated using three critical performance metrics: fast-charge capability, capacity retention, and gravimetric energy density. We build upon the literature by utilizing diffraction techniques to detect silicon amorphization, thus utilization, and understand how this is affected by formulation and cycling.
We also utilize first-of-its-kind operando magnetic dilatometry to explore the effects of formulation, capacity ratio, and electrolyte selection on cell expansion in coin cells. We track reversible and irreversible cell expansions. Our measurements reveal that reversible expansions scale with cell discharge capacity and are most sensitive to the mechanical properties of the electrode. Meanwhile, irreversible expansions are a symptom of cell degradation mechanisms, with electrolyte composition showing the strongest influence. Ultimately, these measurements shed light on how volumetric energy density evolves with cycling—an important metric for battery integration.
The insights gained through the course of this work are expected to inform continued electrode and cell optimizations, guide definition of product specifications for commercialization, and serve as a catalyst for future research and development of silicon anode electrodes for lithium-ion batteries.PhDMaterials Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/177906/1/luonga_1.pd
Abstract 2556: Loss of progesterone receptor through epigenetic regulation is associated with poor prognosis in multiple solid tumors
No full textAbstract
Introduction: As a tumor suppressor in the endometrium, progesterone and its synthesized analogue progestin have a long history as a treatment for endometrial cancer. Loss of progesterone receptor (PR) in endometrial cancer leads to therapeutic failure, and our group has identified several mechanisms underlying PR loss, most notably epigenetic silencing of PR transcription. Recently, a Finnish group demonstrated that progestin therapy in premenopausal women is associated with a lower incidence of not only endometrial cancer, but also ovarian, pancreatic and lung cancers. This unexpected protective function of progestin in organs outside of the reproductive system led us to hypothesize that tumor progression effects in endometrial, ovarian, pancreatic and lung cancer is occurs due to the loss of progesterone’s protective effects.
Methods and results: Supporting a potential protective role of progesterone, we discovered that PR is downregulated in multiple tumors, including breast, endometrial, ovarian, cervical, pancreatic and lung cancers, and loss of PR was consistently associated with a poor prognosis based on analysis of the Oncomine database. Similarly, PR expression was low in multiple ovarian, pancreatic and lung cancer cells. Mechanistic studies revealed that PR downregulation was mediated by the polycomb-repressor complex and DNA methylation, though the precise mechanism differed among cell lines and cancer types. Treatment with epigenetic modulators, which are FDA-approved for multiple myeloma, restored functional PR expression at both the mRNA and protein level and promoted marked cell death through induction of apoptosis. . Moreover, overexpression of PR or treatment with epigenetic modulators in combination with progesterone enhanced this effect, indicating a key protective role for progesterone signaling through PR.
Conclusion: These data suggest loss of PR may be a general theme for tumorigenesis or disease progression in multiple tumor types beyond the classically studied endometrial cancer. In addition, the epigenetic mechanisms contributing to PR downregulation in endometrial tumors were recapitulated in other tumor types, including ovarian, pancreatic and lung tumors. These studies collectively set the stage for use of progestin therapy in combination with epigenetic modulators, a concept we term “molecularly enhanced progestin therapy,” as a novel therapeutic approach for many cancers. This combinatorial strategy has the power to revitalize the use of epigenetic modulators, which have proved disappointing in solid tumors, as an approach to resensitize cancer cells to a tumor suppressor.
Citation Format: Yiyang Li, Tamar Kavlashvili, Cheng Huang, Yuping Zhang, Xiangbing Meng, Kristina Thiel, Kimberly Leslie, Shujie Yang. Loss of progesterone receptor through epigenetic regulation is associated with poor prognosis in multiple solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2556. doi:10.1158/1538-7445.AM2017-2556</jats:p
Objects Classification and Clutter Types Mapping using Polarimetric Radar Detection Algorithms
No full textStarting from numerical simulation and comparative analysis of different polarimetric detector algorithms using the proposed Gain of Detectability measure, this paper has validated the feasibility and accuracy of polarimetric detectors in scenarios with homogeneous clutter. These algorithms’ application to real radar data with non-homogeneous clutter also shows that detection quality can be seriously improved using detectors that use a priori knowledge of the expected target and clutter polarimetric characteristics. A new application of the Polarimetric Whitening Filter and the Optimal Polarimetric Detector for the classification/mapping of targets and ground-based clutter has been proposed and demonstrated.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Microwave Sensing, Signals & System
Improvement of weak targets detectability in strong clutter using the polarization contrast enhancement
No full textGround clutter signal is a kind of unwanted echoes in target detection radar system, which are normally reflected by ground surface, ground-based objects, and obstacles. It can be collected and characterized in polar coordinates in terms of range and azimuth. By using polarimetric based algorithms, including them single channel detector, the span detector, the power maximization synthesis (PMS) detector, the identity likelihood-ratio-test (ILRT), the polarimetric whitening filter (PWF), and the optimal polarimetric detector (OPD), the target detection radar system can distinguish the characteristics and diversity of multiple targets.In this thesis, a polarimetric radar simulator to generate multi-channel polarimetric signals with specific statistical characteristics has been developed and validated in the simulation. In the measurement, a new noise-based equalization for all polarimetric radar channels has been proposed and tested, which improves the reliability and accuracy of the polarimetric information. After noised-based calibration and model-based decomposition of the polarization covariance matrix, with regenerated measurement slow-time data, a variety of targets in heavy clutter with signal power comparable to the target are detected by polarimetric algorithms in the environment of strong clutters. Starting from numerical simulation and comparison of different detector algorithms, this work has validated the feasibility and accuracy of each detector in realistic scenario. The measurement result agrees with the simulation result that with the use of radar polarimetric information as a priori knowledge, target detection can be improvedby polarimetric detectors.Electrical Engineering | Signals and System
The use of natural light and color in meditation spaces: an application in a pavilion in China
Full text linkThis paper is an exploration of meditation and architectural design methodology, based on the author's critique of the crisis of materialism and pragmatism in contemporary Chinese architecture. Starting from the theories of art, aesthetics, psychology, philosophy and other related "architecture and spatial context" and combining with data analysis, this paper designs a meditative space to guide people's thinking and summarizes a theory of architectural design.
First of all, the author argues the current state of the material crisis in contemporary Chinese architecture and draws out the problem to start thinking about solutions. Then by vertically comparing ancient China and showing case studies, it is argued that light plays an important role in the creation of spatial moods. Preliminary design are proposed through field research combined with the influence of light on people, architectural space and context in the previous paper. Then the author argues that color diversity plays an important role in the creation of spatial mood by comparing European countries (Spain) with case studies, and then the author makes a questionnaire survey and analyzes data in order to find the effect of different colors on human emotions. Finally, through the field research on the color of light inside the space, combined with the influence of light and color on people, architectural space and mood in the previous article, the author proposes the final design
The use of natural light and color in meditation spaces: an application in a pavilion in China
Full text linkThis paper is an exploration of meditation and architectural design methodology, based on the author's critique of the crisis of materialism and pragmatism in contemporary Chinese architecture. Starting from the theories of art, aesthetics, psychology, philosophy and other related "architecture and spatial context" and combining with data analysis, this paper designs a meditative space to guide people's thinking and summarizes a theory of architectural design.
First of all, the author argues the current state of the material crisis in contemporary Chinese architecture and draws out the problem to start thinking about solutions. Then by vertically comparing ancient China and showing case studies, it is argued that light plays an important role in the creation of spatial moods. Preliminary design are proposed through field research combined with the influence of light on people, architectural space and context in the previous paper. Then the author argues that color diversity plays an important role in the creation of spatial mood by comparing European countries (Spain) with case studies, and then the author makes a questionnaire survey and analyzes data in order to find the effect of different colors on human emotions. Finally, through the field research on the color of light inside the space, combined with the influence of light and color on people, architectural space and mood in the previous article, the author proposes the final design
Yiyang Cheng, Composition In a Graduate Recital, April 4, 2024 [program]
Full text linkProgram of a music recitals given by faculty, students, or guest artists from the School of Music at the University of Northern Iowa.https://scholarworks.uni.edu/recital_programs/1643/thumbnail.jp
- …
