Influence of size reduction of fly ash particles by grinding on the chemical properties of geopolymers

Chemical properties of geopolymers were evaluated from the reduction of fly ash particle size by grinding. X-ray diffraction determined that at early curing ages new crystalline phases appear in the matrix of the geopolymer and they remain for 28 days, with increases in intensities up to 60%. In Fourier transform infrared spectroscopy, displacements were identified in the main band of the geopolymers at higher wavenumbers, attributed to the greater rigidity in the structures of the aluminosilicate gel due to the increase of the reaction products in the geopolymers obtained through fly ashsubjected to previous grinding, which is observable in the geopolymers matrix. Results indicate that the reduction of fly ash particle size by grinding has an influence on the chemical properties of geopolymers.Peer ReviewedPostprint (published version

Quantitative criticism of literary relationships

Authors often convey meaning by referring to or imitating prior works of literature, a process that creates complex networks of literary relationships ("intertextuality") and contributes to cultural evolution. In this paper, we use techniques from stylometry and machine learning to address subjective literary critical questions about Latin literature, a corpus marked by an extraordinary concentration of intertextuality. Our work, which we term "quantitative criticism," focuses on case studies involving two influential Roman authors, the playwright Seneca and the historian Livy. We find that four plays related to but distinct from Seneca's main writings are differentiated from the rest of the corpus by subtle but important stylistic features. We offer literary interpretations of the significance of these anomalies, providing quantitative data in support of hypotheses about the use of unusual formal features and the interplay between sound and meaning. The second part of the paper describes a machine-learning approach to the identification and analysis of citational material that Livy loosely appropriated from earlier sources. We extend our approach to map the stylistic topography of Latin prose, identifying the writings of Caesar and his near-contemporary Livy as an inflection point in the development of Latin prose style. In total, our results reflect the integration of computational and humanistic methods to investigate a diverse range of literary questions

Evaluación y comparación de geopolimeros obtenidos de dos cenizas volantes mexicanas

Esta investigación se realizó con el fin de determinar las diferencias existentes en los geopolimeros obtenidos de dos tipos de cenizas volantes, las cuales fueron caracterizadas mediante FRX, DRX, FT-IT, del mismo modo se determinaron sus propiedades físicas por picnometría, adsorción de gases (método BET), DTP y MEB. El proceso de activación se llevó a cabo con NaOH 8M a 80°C por 3, 7, 14, 21, 28 y 90 días, realizando ensayos de compresión y módulo dinámico a los mismos, obteniendo una mejora en los resultados conforme aumenta el tiempo de curado, además se demostró que la variación de los contenidos óxidos y las propiedades físicas de las cenizas de partida, juegan uno de los factores más importantes en el desarrollo de los geles producto de reacción (determinado por TGA, FT-IR, DRX y MEB) y por ello la obtención de mejores propiedades mecánicas. (ANGLÈS) This research was conducted in order to determine the differences in the geopolymer obtained from two types of fly ash, which were characterized by XRF, XRD, FT-IR, just as its physical properties were determined by pycnometry, gas adsorption (BET method), PSD and SEM. The activation process was conducted with NaOH 8M at 80°C for 3, 7, 14, 21, 28 and 90 days, to performing compression tests and dynamic module, obtaining a improved results with increasing cure time, also it showed that the variation of oxide content and the physical properties of the starting ash, play one of the most important factors in the development of the reaction product gels (determined by TGA, FT-IR, XRD and SEM) and thus obtaining better mechanical properties.Postprint (published version

Traversing Dimensions: An Exploration of Diversity in Science Fiction

Science fiction literature is often seen as a space traditionally reserved for white, male authors and audiences. However, with growing interest in Afrofuturism and exploration of identity, there is clearly a desire to discuss the alterity of science fiction. This exhibit aims to contextualize past and present diverse works and authors of sci-fi, including speculative fiction. We feature traditionally underrepresented perspectives from Black, East and South Asian, Latinx, Latin American, LGBTQIA, feminist and intersectional authors. By traversing the more familiar, we can explore new dimensions and consider how these horizons mirror our current time and space.UT Librarie

Diversity in Sci-Fi

“Diversity in Sci-Fi” aims to spotlight the many voices present in UT’s science fiction collection. Titles were selected for representing authors and subject matter not found in the historically white science-fiction literature. Books on display are a part of the Library’s circulating materials, so they are accessible for students to engage with after the display. “Diversity in Sci-Fi” was located on the third floor of the PCL and was on view October 1, 2018 through October 31, 2018 in conjunction with “Traversing Dimensions” a science fiction exhibit located in the Scholars Commons. The related science-fiction LibGuide can be accessed here: https://guides.lib.utexas.edu/scifi/homeUT Librarie

Size matters – and how you measure it: a gram-negative antibacterial example exceeding typical molecular weight limits

From a porin permeation perspective, we characterized a monobactam antibiotic (compound 1) which has a higher molecular weight (MW) than the upper limit of 600 Da typically applied in designing such compounds, yet the compound is active against Gram-negative bacteria. Despite a MW of 692 Da, the compound is able to adopt a compact conformation based on 2D NMR data. The dimensions, projection area and dipole moment derived from this conformation are compatible with porin permeation, as are locations of polar groups upon superimposition to the crystal structure of a known antibiotic, ampicillin, bound to E. coli OmpF porin crystal structure. MIC shifts in a porin knockout strain are also consistent with compound 1 predominately permeating through porins. In conclusion, we describe a carefully characterized case of a molecule outside default design parameters where MW does not adequately characterize the 3D shape which is more directly related to permeability. Leveraging 3D design criteria would open up additional chemical space currently underutilized due to limitations perceived in 2D

Evaluación y comparación de geopolimeros obtenidos de dos cenizas volantes mexicanas

Esta investigación se realizó con el fin de determinar las diferencias existentes en los geopolimeros obtenidos de dos tipos de cenizas volantes, las cuales fueron caracterizadas mediante FRX, DRX, FT-IT, del mismo modo se determinaron sus propiedades físicas por picnometría, adsorción de gases (método BET), DTP y MEB. El proceso de activación se llevó a cabo con NaOH 8M a 80°C por 3, 7, 14, 21, 28 y 90 días, realizando ensayos de compresión y módulo dinámico a los mismos, obteniendo una mejora en los resultados conforme aumenta el tiempo de curado, además se demostró que la variación de los contenidos óxidos y las propiedades físicas de las cenizas de partida, juegan uno de los factores más importantes en el desarrollo de los geles producto de reacción (determinado por TGA, FT-IR, DRX y MEB) y por ello la obtención de mejores propiedades mecánicas. (ANGLÈS) This research was conducted in order to determine the differences in the geopolymer obtained from two types of fly ash, which were characterized by XRF, XRD, FT-IR, just as its physical properties were determined by pycnometry, gas adsorption (BET method), PSD and SEM. The activation process was conducted with NaOH 8M at 80°C for 3, 7, 14, 21, 28 and 90 days, to performing compression tests and dynamic module, obtaining a improved results with increasing cure time, also it showed that the variation of oxide content and the physical properties of the starting ash, play one of the most important factors in the development of the reaction product gels (determined by TGA, FT-IR, XRD and SEM) and thus obtaining better mechanical properties

Evaluación y comparación de geopolimeros obtenidos de dos cenizas volantes mexicanas

Esta investigación se realizó con el fin de determinar las diferencias existentes en los geopolimeros obtenidos de dos tipos de cenizas volantes, las cuales fueron caracterizadas mediante FRX, DRX, FT-IT, del mismo modo se determinaron sus propiedades físicas por picnometría, adsorción de gases (método BET), DTP y MEB. El proceso de activación se llevó a cabo con NaOH 8M a 80°C por 3, 7, 14, 21, 28 y 90 días, realizando ensayos de compresión y módulo dinámico a los mismos, obteniendo una mejora en los resultados conforme aumenta el tiempo de curado, además se demostró que la variación de los contenidos óxidos y las propiedades físicas de las cenizas de partida, juegan uno de los factores más importantes en el desarrollo de los geles producto de reacción (determinado por TGA, FT-IR, DRX y MEB) y por ello la obtención de mejores propiedades mecánicas. (ANGLÈS) This research was conducted in order to determine the differences in the geopolymer obtained from two types of fly ash, which were characterized by XRF, XRD, FT-IR, just as its physical properties were determined by pycnometry, gas adsorption (BET method), PSD and SEM. The activation process was conducted with NaOH 8M at 80°C for 3, 7, 14, 21, 28 and 90 days, to performing compression tests and dynamic module, obtaining a improved results with increasing cure time, also it showed that the variation of oxide content and the physical properties of the starting ash, play one of the most important factors in the development of the reaction product gels (determined by TGA, FT-IR, XRD and SEM) and thus obtaining better mechanical properties

Influence of size reduction of fly ash particles by grinding on the chemical properties of geopolymers

Chemical properties of geopolymers were evaluated from the reduction of fly ash particle size by grinding. X-ray diffraction determined that at early curing ages new crystalline phases appear in the matrix of the geopolymer and they remain for 28 days, with increases in intensities up to 60%. In Fourier transform infrared spectroscopy, displacements were identified in the main band of the geopolymers at higher wavenumbers, attributed to the greater rigidity in the structures of the aluminosilicate gel due to the increase of the reaction products in the geopolymers obtained through fly ashsubjected to previous grinding, which is observable in the geopolymers matrix. Results indicate that the reduction of fly ash particle size by grinding has an influence on the chemical properties of geopolymers.Peer Reviewe

The monobactam LYS228: mode of action and mechanisms decreasing in vitro susceptibility of Escherichia coli and Klebsiella pneumoniae

The monobactam chemical scaffold is attractive for the development of new agents to treat infections caused by drug-resistant Gram-negative bacteria since it is stable to metallo-β-lactamases (MBLs). However, the clinically used monobactam aztreonam lacks stability to serine β-lactamases (SBLs) that are often co-expressed with MBLs. The novel monobactam LYS228 is stable to MBLs and most SBLs. LYS228 bound purified Escherichia coli penicillin binding protein 3 (PBP3) similarly to ATM (k2/Kd = 367504 s-1M-1 and 409229 s-1M-1, respectively) according to stopped-flow fluorimetry. A gel-based PBP binding assay showed that LYS228 bound mainly to E. coli PBP3, with weaker binding to PBP1a and PBP1b. Exposing E. coli cells to LYS228 caused filamentation, consistent with cell division defects resulting from inhibition of PBP3. No single-step mutants were selected from twelve Enterobacteriaceae strains expressing different classes of β-lactamases at 8X the minimum inhibitory concentration (MIC) of LYS228 (frequency <2.5x10-9). At 4X the MIC, mutants were selected from two of twelve strains at frequencies of 1.8x10-7 and 4.2x10-9. LYS228 MICs were ≤ 2 μg/mL against all mutants. These frequencies compared favorably to those obtained with meropenem and tigecycline. Mutations decreasing LYS228 susceptibility occurred in ramR and cpxA (Klebsiella pneumoniae) and baeS (E. coli and K. pneumoniae). Susceptibility of E. coli ATCC 25922 to LYS228 decreased 256-fold (MIC 0.125 to 32 µg/mL) after 20 serial passages. Mutants had accumulated mutations in ftsI (encoding the target, PBP3), baeR, acrD, envZ, sucB and rfaI. These results support the continued development of LYS228, which is currently undergoing Phase II clinical trials for complicated intraabdominal infection and complicated urinary tract infection (Clinicaltrials.gov NCT03354754)