178,237 research outputs found
Magnesium-based glasses prepared by sol-gel processing for use as supplementary cementitious materials
No full textAbstract
For decades, supplementary cementitious materials (SCMs) have been utilized as clinker substitutes as one of the strategies to mitigate the CO2 emissions associated with Portland cement production. However, traditional SCMs (e.g., coal fly ash, silica fume, and blast furnace slag) are being phased out, as they are insufficient to enable high volume clinker substitution. Therefore, alternative SCMs are actively being sought to meet market demand. Synthetic glasses may be a potential source of SCMs due to their pozzolanic activity and tunable properties. The chemical composition of glasses determines their pozzolanic activity, with Ca-based glasses being predominantly studied owing to their high reactivity. However, this leads to the same inherent CO2 emissions as for cement, originating from the production of CaO from CaCO3.
This thesis investigates Mg-based silicate glasses synthesized via the sol-gel method, tuning their composition for higher pozzolanic activity. The feasibility of using Mg-based silicate glasses as SCMs was studied through three main pathways:
(1) Development of a binary Mg-Si sol-gel glass system: The impact of varying Mg concentrations on the glass reactivity was assessed (Publication Ⅰ).
(2) Introduction of Fe into the Mg-Si system: Varying concentrations of Fe3+/ Fe2+ were incorporated into Mg-Si glasses, investigating changes in reactivity (Publications Ⅱ, Ⅲ).
(3) Assessment of cementitious performance: The pozzolanic activity of Mg-based glasses was evaluated, and their impact on the properties and performance of cementitious systems was studied (Publication Ⅳ).
The research revealed the high elemental solubility of the synthetic glasses, indicating their high reactivity, and demonstrated pozzolanic activity exceeding that of conventional SCMs such as fly ash slag. These findings provide a preliminary assessment of the potential for using Mg silicate glasses as novel SCMs with the aim of reducing CO2 emissions. Original papers Jiang, C., Ramteke, D. D., Li, J., Sliz, R., Sreenivasan, H., Cheeseman, C., & Kinnunen, P. (2023). Preparation and characterization of binary Mg-silicate glasses via Sol-Gel route. Journal of Non-Crystalline Solids, 606, 122204. https://doi.org/10.1016/j.jnoncrysol.2023.122204 https://doi.org/10.1016/j.jnoncrysol.2023.122204 Self-archived version Jiang, C., Santos, H. S., Yliniemi, J., Lindén, J., Ramteke, D. D., Illikainen, M., Cheeseman, C., & Kinnunen, P. (2024). Fe-bearing magnesium silicate glasses for potential supplementary cementitious applications. Frontiers in Materials, 11, 1509403. https://doi.org/10.3389/fmats.2024.1509403 https://doi.org/10.3389/fmats.2024.1509403 Self-archived version Jiang, C., Yliniemi, J., Santos, H. S., Lindén, J., Ramteke, D.D., Cheeseman, C., & Kinnunen, P. (2024). Optimizing Fe(II)/Fe(III)-bearing magnesium silicate glasses for applications in supplementary cementitious materials. Manuscript submitted for publication. Jiang, C., Santos, H. S., Ahmad, L., Yliniemi, J., Cheeseman, C., & Kinnunen, P. (2025). Properties of Fe-bearing Mg silicate glasses as novel supplementary cementitious materials. Manuscript submitted for publication. Tiivistelmä
Jo vuosikymmenten ajan sementin seosaineita (SCM) on käytetty klinkkerin korvikkeina tavoitteena vähentää portlandsementin tuotannossa syntyviä CO2-päästöjä. Perinteisten SCM-materiaalien, kuten lentotuhkan, silikajauheen ja masuunikuonan, saatavuus ei kuitenkaan riitä mahdollistamaan korkeaa klinkkerin korvausastetta. Siksi on tarpeen kehittää uusia SCM-materiaaleja markkinoiden tarpeiden täyttämiseksi. Synteettiset lasit voivat olla potentiaalinen vaihtoehto niiden potsolaanisen aktiivisuuden ja säädettävien ominaisuuksien ansiosta. Lasien kemiallinen koostumus määrittää niiden potsolaanisen aktiivisuuden, ja enimmäkseen on tutkittu Ca-pohjaisia laseja niiden korkean reaktiivisuuden vuoksi. Tämä johtaa kuitenkin samoihin luontaisiin CO2-päästöihin kuin sementin tuotannossa, koska CaO:ta tuotetaan CaCO3:sta.
Tämä väitöskirja tutkii Mg-pohjaisia silikaattilaseja, jotka tuotetaan sol-gel-menetelmällä, jossa lasien koostumusta säädetään korkeamman potsolaanisen aktiivisuuden saavuttamiseksi. Mg-pohjaisten silikaattilasien käyttökelpoisuutta SCM-materiaaleina tutkittiin kolmen pääasiallisen lähestymistavan kautta:
(1) Binaarisen Mg-Si sol-gel-lasin kehitys: Eri Mg-pitoisuuksien vaikutuksia lasin reaktiivisuuteen arvioitiin (julkaisu I).
(2) Fe:n lisääminen Mg-Si-järjestelmään: Mg-Si-laseihin lisättiin eri pitoisuuksia Fe3+/Fe2+:aa, ja niiden vaikutusta reaktiivisuuteen tutkittiin (julkaisut II, III).
(3) Sementtimäisen suorituskyvyn arviointi: Mg-pohjaisten lasien potsolaanista aktiivisuutta arvioitiin, ja niiden vaikutusta seostettujen sementtien ominaisuuksiin ja suorituskykyyn tutkittiin (julkaisu IV).
Tutkimus paljastaa synteettisten lasien korkean alkuaineliukoisuuden, mikä viittaa niiden korkeaan reaktiivisuuteen, sekä osoittaa, että niiden potsolaaninen aktiivisuus ylittää perinteiset SCM:t, kuten lentotuhkan ja kuonan. Nämä havainnot tarjoavat alustavan arvion Mg-silikaattilasien potentiaalista uusina SCM-materiaaleina, joiden tavoitteena on CO2-päästöjen vähentäminen. Osajulkaisut Jiang, C., Ramteke, D. D., Li, J., Sliz, R., Sreenivasan, H., Cheeseman, C., & Kinnunen, P. (2023). Preparation and characterization of binary Mg-silicate glasses via Sol-Gel route. Journal of Non-Crystalline Solids, 606, 122204. https://doi.org/10.1016/j.jnoncrysol.2023.122204 https://doi.org/10.1016/j.jnoncrysol.2023.122204 Rinnakkaistallennettu versio Jiang, C., Santos, H. S., Yliniemi, J., Lindén, J., Ramteke, D. D., Illikainen, M., Cheeseman, C., & Kinnunen, P. (2024). Fe-bearing magnesium silicate glasses for potential supplementary cementitious applications. Frontiers in Materials, 11, 1509403. https://doi.org/10.3389/fmats.2024.1509403 https://doi.org/10.3389/fmats.2024.1509403 Rinnakkaistallennettu versio Jiang, C., Yliniemi, J., Santos, H. S., Lindén, J., Ramteke, D.D., Cheeseman, C., & Kinnunen, P. (2024). Optimizing Fe(II)/Fe(III)-bearing magnesium silicate glasses for applications in supplementary cementitious materials. Manuscript submitted for publication. Jiang, C., Santos, H. S., Ahmad, L., Yliniemi, J., Cheeseman, C., & Kinnunen, P. (2025). Properties of Fe-bearing Mg silicate glasses as novel supplementary cementitious materials. Manuscript submitted for publication. Academic dissertation to be presented with the assent of the Doctoral Programme Committee of Technology and Natural Sciences of the University of Oulu for public defence in the Wetteri auditorium (IT115), Linnanmaa, on 25 April 2025, at 12 noonAbstract
For decades, supplementary cementitious materials (SCMs) have been utilized as clinker substitutes as one of the strategies to mitigate the CO2 emissions associated with Portland cement production. However, traditional SCMs (e.g., coal fly ash, silica fume, and blast furnace slag) are being phased out, as they are insufficient to enable high volume clinker substitution. Therefore, alternative SCMs are actively being sought to meet market demand. Synthetic glasses may be a potential source of SCMs due to their pozzolanic activity and tunable properties. The chemical composition of glasses determines their pozzolanic activity, with Ca-based glasses being predominantly studied owing to their high reactivity. However, this leads to the same inherent CO2 emissions as for cement, originating from the production of CaO from CaCO3.
This thesis investigates Mg-based silicate glasses synthesized via the sol-gel method, tuning their composition for higher pozzolanic activity. The feasibility of using Mg-based silicate glasses as SCMs was studied through three main pathways:
(1) Development of a binary Mg-Si sol-gel glass system: The impact of varying Mg concentrations on the glass reactivity was assessed (Publication Ⅰ).
(2) Introduction of Fe into the Mg-Si system: Varying concentrations of Fe3+/ Fe2+ were incorporated into Mg-Si glasses, investigating changes in reactivity (Publications Ⅱ, Ⅲ).
(3) Assessment of cementitious performance: The pozzolanic activity of Mg-based glasses was evaluated, and their impact on the properties and performance of cementitious systems was studied (Publication Ⅳ).
The research revealed the high elemental solubility of the synthetic glasses, indicating their high reactivity, and demonstrated pozzolanic activity exceeding that of conventional SCMs such as fly ash slag. These findings provide a preliminary assessment of the potential for using Mg silicate glasses as novel SCMs with the aim of reducing CO2 emissions.Tiivistelmä
Jo vuosikymmenten ajan sementin seosaineita (SCM) on käytetty klinkkerin korvikkeina tavoitteena vähentää portlandsementin tuotannossa syntyviä CO2-päästöjä. Perinteisten SCM-materiaalien, kuten lentotuhkan, silikajauheen ja masuunikuonan, saatavuus ei kuitenkaan riitä mahdollistamaan korkeaa klinkkerin korvausastetta. Siksi on tarpeen kehittää uusia SCM-materiaaleja markkinoiden tarpeiden täyttämiseksi. Synteettiset lasit voivat olla potentiaalinen vaihtoehto niiden potsolaanisen aktiivisuuden ja säädettävien ominaisuuksien ansiosta. Lasien kemiallinen koostumus määrittää niiden potsolaanisen aktiivisuuden, ja enimmäkseen on tutkittu Ca-pohjaisia laseja niiden korkean reaktiivisuuden vuoksi. Tämä johtaa kuitenkin samoihin luontaisiin CO2-päästöihin kuin sementin tuotannossa, koska CaO:ta tuotetaan CaCO3:sta.
Tämä väitöskirja tutkii Mg-pohjaisia silikaattilaseja, jotka tuotetaan sol-gel-menetelmällä, jossa lasien koostumusta säädetään korkeamman potsolaanisen aktiivisuuden saavuttamiseksi. Mg-pohjaisten silikaattilasien käyttökelpoisuutta SCM-materiaaleina tutkittiin kolmen pääasiallisen lähestymistavan kautta:
(1) Binaarisen Mg-Si sol-gel-lasin kehitys: Eri Mg-pitoisuuksien vaikutuksia lasin reaktiivisuuteen arvioitiin (julkaisu I).
(2) Fe:n lisääminen Mg-Si-järjestelmään: Mg-Si-laseihin lisättiin eri pitoisuuksia Fe3+/Fe2+:aa, ja niiden vaikutusta reaktiivisuuteen tutkittiin (julkaisut II, III).
(3) Sementtimäisen suorituskyvyn arviointi: Mg-pohjaisten lasien potsolaanista aktiivisuutta arvioitiin, ja niiden vaikutusta seostettujen sementtien ominaisuuksiin ja suorituskykyyn tutkittiin (julkaisu IV).
Tutkimus paljastaa synteettisten lasien korkean alkuaineliukoisuuden, mikä viittaa niiden korkeaan reaktiivisuuteen, sekä osoittaa, että niiden potsolaaninen aktiivisuus ylittää perinteiset SCM:t, kuten lentotuhkan ja kuonan. Nämä havainnot tarjoavat alustavan arvion Mg-silikaattilasien potentiaalista uusina SCM-materiaaleina, joiden tavoitteena on CO2-päästöjen vähentäminen
Determination of Absolute Configuration Using Ab Initio Calculation of Optical Rotation
No full textAb initio Density Functional Theory (DFT) calculations of transparent
spectral region, discrete frequency specific rotations were used to assign the absolute
configurations (ACs) of: 1, 2H-naphtho[1,8-bc]thiophene 1-oxide; 2, m-F-phenyl glycidic
acid methyl ester; 3, o-Br-phenyl glycidic acid methyl ester; 4, p-CH3-phenyl glycidic
acid methyl ester; 5, 2-(1-hydroxyethyl)-chromen-4-one; and 6, 6-Br-2-(1-hydroxyethyl)-
chromen-4-one. The ACs of 5 and 6 were previously determined via X-ray crystallography
to be: 5, R(−)/S(+); 6, R(+)/S(−). The ACs obtained using []D are the same for
both 5 and 6: R(+)/S(−). We conclude that the previously reported AC of 5 is incorrec
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Polarizable Embedding Approach for the Analytical Calculation of Raman and Raman Optical Activity Spectra of Solvated Systems
No full textWe present an analytical formulation and implementation of Raman and Raman Optical Activity (ROA) spectra within a three-layer fully polarizable Quantum Mechanical (QM)/ Molecular Mechanics (MM)/Polarizable Continuum Model (PCM) approach. Polarization effects in the MM layer are modeled by exploiting the Fluctuating Charges (FQ) method, in which MM solvent atoms are endowed with electric charges that can be mutually polarized by the solute QM density. Because of its fully polarizable atomistic description, QM/FQ/PCM is able to account for specific solvent effects like those due to hydrogen bonds, providing a physical picture for protic solvents such as water. Applications to aqueous (R)-methyloxirane and (S)-methyllactate are presented, and results are compared with available experimental data
tedcheese/RSOS-NPAC-abundance: RSOS-NPAC-abundance-v1.0
No full text<p>This archive contains photo-ID data sourced from Happywhale.com and R code for preprocessing and creating abundance estimations</p>
<p>Please note data has many copyrights and can only be used for recreation of abundance estimation in the Cheeseman et al RSOS manuscript; all other use requires permission from the authors</p>
<p>The data found here is demised from the original export format from Happywhale of all identified 2001-2022 encounters of humpback whales in the North Pacific population, as of 15 December 2023. Data includes all Pacific Arctic encounters, all Pacific Ocean encounters from Honduras north, and all Panama through Nicaragua encounters from November 7 through May of each study period year.</p>
<p>Please contact <a href="mailto:[email protected]">[email protected]</a> for any questions or use</p>
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Population Ecology of Thelymitra matthewsii Cheeseman Orchidaceae, in Northern New Zealand
No full textThe terrestrial orchid Thelymitra matthewsii Cheeseman, uncommon in New Zealand, was studied to increase knowledge of the species life cycle, morphology and ecology. Results will enhance future conservation management for the species.
New information related to the morphology of T. matthewsii was obtained. The species was found to emerge in one of four discrete life stages of distinctive morphology and height range that remained constant for the season, not developing into a more advanced life stage. The leaf of the three pre adult life stages designated a hook, a spiral, and a non flowering stage, did not inflate at the base, but rose smoothly from the tuber. Apparent morphological differences in the column between descriptions of the Australian taxon and the small New Zealand sample examined suggested further study was needed.
Comprehensive monthly monitoring was carried out at five study sites in three locations in the Te Paki area of the Far North, from 2002 to 2004. No patterns emerged in plant life stage succession, flowering, and presence or absence at labels reinforcing the concept that variability was a common component of the population census.
Seasonal and partial absence was a major component of the populations. An average of 32.8% of plants, over five study sites, were present throughout three seasons, while 66.9% were recorded as absent (not visible) at monitoring. New plants appearing in 2003 and 2004 showed a high percentage of subsequent absence (mean 85.7%).
To determine population stability, recruitment and absence were compared. Plant absence exceeded recruitment by 7% (mean plant absence 30.5%; mean recruitment 23.4%). Plants continued to appear during the monitoring period, and labeled plants increased two-fold over commencement numbers.
Adults recorded as 28% of labeled plants over three seasons, were out numbered by pre-flowering stages. Only 5% of population numbers exhibited succession from a smaller to a flowering plant. Life stage modeling indicated a life stage was more likely to be followed by the same stage than an expected successive stage.
Thelymitra matthewsii was found to be present in four substrates in the Far North.
The survey of vegetation found the indigenous species Kunzea ericoides and the exotic Hakea gibbosa dominant for both height, and cover. Litter and bare ground dominated ground cover. Differences in vegetation and ground cover, of sites supporting T. matthewsii and comparison sites that did not, were minor and suggested that another factor, for example a suitable fungal partner, influenced the species presence or absence.
The results of the study indicated the present threat classification of Thelymitra matthewsii is inadequate in the light of the species relatively circumscribed, widely separated habitats, the small number of reproducing individuals and vulnerability to habitat modification
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Polarizable Continuum Model (PCM) calculations of solvent effects on optical rotations of chiral molecule
No full textA new theory of solvent effects on the optical rotations of chiral molecules is presented. The frequency- dependent electric dipole-magnetic dipole polarizability, R(ν), is calculated using density functional theory (DFT). Solvent effects are included using the polarizable continuum model (PCM). DFT/PCM calculations of sodium D line specific rotations, [R]D, have been carried out for seven conformationally rigid chiral organic molecules (fenchone, camphor, R-pinene, -pinene, camphorquinone, verbenone, and methyloxirane) for a diverse set of seven solvents (cyclohexane, carbon tetrachloride, benzene, chloroform, acetone, methanol, and acetonitrile). The predicted variation in [R]D for the solvents cyclohexane, acetone, methanol, and acetonitrile are in excellent agreement with experiment for all seven molecules. For the solvents carbon tetrachloride, benzene, and chloroform, agreement is much poorer. Since only electrostatic solute-solvent interactions are included in the PCM, our results lead to the conclusion that, for the seven molecules studied, in cyclohexane, acetone, methanol, and acetonitrile electrostatic effects are dominant while in carbon tetrachloride, benzene, and chloroform other nonelectrostatic effects are more important. The observed variations in [R]D with solvent are inconsistent, both qualitatively and quantitatively, with the variations predicted by the equation [alpha]_D(solvent)={[alpha]_D (gas)}(n^2 + 2)/3
Letter from R. R. Zellick, Assistant Trust Officer, Anglo California National Bank of San Francisco, to Joseph R. Goodman, October 2, 1942
No full textLetter from R. R. Zellick, Assistant Trust Officer at The Anglo California National Bank of San Francisco, to Joseph R. Goodman, regarding property owned by Dave Tatsuno. Zellick mentions a dispute between current tenants and Tatsuno, and that Tatsuno has asked Goodman to help locate trustworthy tenants.Personal correspondence, organizational records, government documents, publications, and other papers created or collected by Joseph R. Goodman documenting the forced removal and incarceration of Japanese Americans during World War II, as well as organized resistance to incarceration. Included in the collection are records of the Japanese Young Men's Christian Association and the Japanese American Citizens' League in San Francisco, including papers of the Japanese YMCA's executive secretary Lincoln Kanai; Sakai family papers; Goodman's correspondence to and from Japanese American incarcerees, organizations opposing forced removal and incarceration of Japanese Americans, the War Relocation Authority, and others; publications, photographs, and ephemera from the Topaz Relocation Center, where Goodman taught high school; War Relocation Authority records and publications; and newspaper clippings, pamphlets, and reports about forced removal and incarceration created by various government, religious, and civic organizations, in California and nationwide
- …
