179,381 research outputs found
Highly porous alkali activated foams for water and wastewater treatment
No full textAbstract
Alkali-activated materials (AAMs) have diverse applications in water and wastewater treatment. In this thesis, porous AAM foams were prepared with the goal to explore their potential use in new applications for water and wastewater treatment, namely adsorptive filters, point-of-use water disinfection, and separation of microplastics.
The adsorptive filters were prepared from blast furnace slag and optimized by comparing five different surfactants and doses of H2O2. Porous AAM exhibiting the highest mechanical strength was investigated for methylene blue adsorption. To further enhance the adsorption performance, a lignin-containing composite foam was prepared. In the dynamic adsorption experiments, the highest adsorption amount obtained with the lignin-composite foam was ~40 mg/g. Moreover, peracetic acid was investigated as an alternative foaming agent in the preparation of porous AAMs. During the investigation, lower volume expansion and faster reaction kinetics with reduced setting time were observed for peracetic acid-based porous AAM compared to H2O2-based porous AAM.
To develop material for point-of-use water disinfection, the first goal was to achieve comparable water permeability to traditional ceramic filters by varying the amount of hydrogen peroxide. An optimized foam was then treated with colloidal Ag solution to explore its potential use in disinfecting water for 10 weeks. The modified foam demonstrated a significant reduction (2.84 log10 units) in E. coli bacteria compared to an unmodified filter (1.57 log10 units). Additionally, the environmental impact of the porous AAM was analyzed through life cycle assessment and found to be lower than that of conventional ceramic filter.
Finally, to develop material capable of separating microplastics, porous AAM surface was modified with triethoxy(octyl)silane to render it superhydrophobic. The modified porous AAM demonstrated over 99% separation efficiency when treating 30 L of model water containing 5 mg/L of polyethylene microspheres (53-63 μm). Its performance was also evaluated in treating laundry effluent, where the modified porous AAM achieved approximately 84% separation compared to around 52% for the unmodified porous AAM. Original papers Bhuyan, M. A. H., Gebre, R. K., Finnilä, M. A. J., Illikainen, M., & Luukkonen, T. (2022). Preparation of filter by alkali activation of blast furnace slag and its application for dye removal. Journal of Environmental Chemical Engineering, 10(1), 107051. https://doi.org/10.1016/j.jece.2021.107051 https://doi.org/10.1016/j.jece.2021.107051 Self-archived version Bhuyan, M. A. H., & Luukkonen, T. (2024). Adsorption of methylene blue by composite foams containing alkali-activated blast furnace slag and lignin. International Journal of Environmental Science and Technology, 21(4), 3789–3802. https://doi.org/10.1007/s13762-023-05245-5 https://doi.org/10.1007/s13762-023-05245-5 Self-archived version Bhuyan, M. A. H., Kurtulus, C., Heponiemi, A., & Luukkonen, T. (2023). Peracetic acid as a novel blowing agent in the direct foaming of alkali-activated materials. Applied Clay Science, 231, 106727. https://doi.org/10.1016/j.clay.2022.106727 https://doi.org/10.1016/j.clay.2022.106727 Self-archived version Bhuyan, M. A. H., Karkman, A., Prokkola, H., Chen, B., Perumal, P., & Luukkonen, T. (2024). Alkali-activated foams coated with colloidal Ag for point-of-use water disinfection. ACS ES&T Water, 4(2), 687–697. https://doi.org/10.1021/acsestwater.3c00711 https://doi.org/10.1021/acsestwater.3c00711 Self-archived version Bhuyan, M. A. H., Busquets, R., Campos, L. C., & Luukkonen, T. (2024). Separation of microplastics from water using superhydrophobic silane-coupling-agent-modified geopolymer foam. Separation and Purification Technology, 339, 126709. https://doi.org/10.1016/j.seppur.2024.126709 https://doi.org/10.1016/j.seppur.2024.126709 Self-archived version Abstrakti
Alkaliaktivoiduilla materiaaleilla on runsaasti erilaisia sovelluksia veden ja jäteveden käsittelyssä. Tässä väitöskirjassa valmistettiin huokoisia alkaliaktivoituja vaahtoja tavoitteena selvittää niiden uusia hyödyntämismahdollisuuksia adsorboivina suodatinmateriaaleina, veden desinfioinnissa ja mikromuovin erottamisessa.
Masuunikuonasta valmistettujen adsorboivien suodattimien koostumus optimoitiin muuttamalla valmistuksessa käytetyn pinta-aktiivisen aineen tyyppiä sekä vaahdotinaineena toimivan vetyperoksidin lisäysmäärää. Optimoidulla materiaalilla tutkittiin metyleenisinisen adsorptiota vedestä. Adsorptiokyvyn lisäämiseksi valmistettiin ligniiniä sisältävää komposiittimateriaalia. Dynaamisessa metyleenisinisen adsorptiokokeessa suurin adsorptiomäärä ligniinikomposiitille oli ~40 mg/g. Lisäksi peretikkahappoa tutkittiin vaihtoehtoisena vaahdotusaineena. Peretikkahappoa käytettäessä havaittiin pienempi turpoaminen valmistuksen aikana ja lyhyempi kovettumisaika verrattuna vetyperoksidilla valmistettuihin vaahtoihin.
Tutkimuksen seuraavassa osassa tutkittiin veden desinfiointia. Alkaliaktivoituja vaahtoja valmistettiin metakaoliinista, masuunikuonasta ja niiden seoksista tavoitteena saavuttaa samanlainen veden läpäisevyys kuin keraamisilla suodattimilla. Tämän jälkeen optimoitua vaahtoa käsiteltiin kolloidisella hopealiuoksella ja sen käyttömahdollisuuksia veden desinfioinnissa tutkittiin 10 viikon ajan. Hopeaa sisältävä vaahto osoitti merkittävää E. coli -bakteerien vähenemistä (2,84 log10) verrattuna hopeaa sisältämättömään suodattimeen (1,57 log10). Lisäksi alkaliaktivoidun vaahdon ympäristövaikutuksia analysoitiin elinkaariarvioinnin avulla ja niiden todettiin olevan pienempiä kuin perinteisen keraamin.
Mikromuovien erottamiseksi alkaliaktivoituja vaahtoja käsiteltiin trietoksi(oktyyli)silaanilla superhydrofobisen pinnan luomiseksi. Käsitelty vaahto poisti yli 99 % mikromuovista kokeessa, jossa käsiteltiin 30 litraa vettä, joka sisälsi 5 mg/l polyetyleenipartikkeleita (koko 53–63 μm). Käsitellyn vaahdon suorituskykyä arvioitiin myös pyykinpesuveden käsittelyssä, jossa sen muovin poistokyky oli noin 84 % kun taas ei-käsitelty vaahto poisti vain 52 %. Osajulkaisut Bhuyan, M. A. H., Gebre, R. K., Finnilä, M. A. J., Illikainen, M., & Luukkonen, T. (2022). Preparation of filter by alkali activation of blast furnace slag and its application for dye removal. Journal of Environmental Chemical Engineering, 10(1), 107051. https://doi.org/10.1016/j.jece.2021.107051 https://doi.org/10.1016/j.jece.2021.107051 Rinnakkaistallennettu versio Bhuyan, M. A. H., & Luukkonen, T. (2024). Adsorption of methylene blue by composite foams containing alkali-activated blast furnace slag and lignin. International Journal of Environmental Science and Technology, 21(4), 3789–3802. https://doi.org/10.1007/s13762-023-05245-5 https://doi.org/10.1007/s13762-023-05245-5 Rinnakkaistallennettu versio Bhuyan, M. A. H., Kurtulus, C., Heponiemi, A., & Luukkonen, T. (2023). Peracetic acid as a novel blowing agent in the direct foaming of alkali-activated materials. Applied Clay Science, 231, 106727. https://doi.org/10.1016/j.clay.2022.106727 https://doi.org/10.1016/j.clay.2022.106727 Rinnakkaistallennettu versio Bhuyan, M. A. H., Karkman, A., Prokkola, H., Chen, B., Perumal, P., & Luukkonen, T. (2024). Alkali-activated foams coated with colloidal Ag for point-of-use water disinfection. ACS ES&T Water, 4(2), 687–697. https://doi.org/10.1021/acsestwater.3c00711 https://doi.org/10.1021/acsestwater.3c00711 Rinnakkaistallennettu versio Bhuyan, M. A. H., Busquets, R., Campos, L. C., & Luukkonen, T. (2024). Separation of microplastics from water using superhydrophobic silane-coupling-agent-modified geopolymer foam. Separation and Purification Technology, 339, 126709. https://doi.org/10.1016/j.seppur.2024.126709 https://doi.org/10.1016/j.seppur.2024.126709 Rinnakkaistallennettu versio 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 Arina auditorium (TA105), Linnanmaa, on 3 May 2024, at 12 noonAbstract
Alkali-activated materials (AAMs) have diverse applications in water and wastewater treatment. In this thesis, porous AAM foams were prepared with the goal to explore their potential use in new applications for water and wastewater treatment, namely adsorptive filters, point-of-use water disinfection, and separation of microplastics.
The adsorptive filters were prepared from blast furnace slag and optimized by comparing five different surfactants and doses of H2O2. Porous AAM exhibiting the highest mechanical strength was investigated for methylene blue adsorption. To further enhance the adsorption performance, a lignin-containing composite foam was prepared. In the dynamic adsorption experiments, the highest adsorption amount obtained with the lignin-composite foam was ~40 mg/g. Moreover, peracetic acid was investigated as an alternative foaming agent in the preparation of porous AAMs. During the investigation, lower volume expansion and faster reaction kinetics with reduced setting time were observed for peracetic acid-based porous AAM compared to H2O2-based porous AAM.
To develop material for point-of-use water disinfection, the first goal was to achieve comparable water permeability to traditional ceramic filters by varying the amount of hydrogen peroxide. An optimized foam was then treated with colloidal Ag solution to explore its potential use in disinfecting water for 10 weeks. The modified foam demonstrated a significant reduction (2.84 log10 units) in E. coli bacteria compared to an unmodified filter (1.57 log10 units). Additionally, the environmental impact of the porous AAM was analyzed through life cycle assessment and found to be lower than that of conventional ceramic filter.
Finally, to develop material capable of separating microplastics, porous AAM surface was modified with triethoxy(octyl)silane to render it superhydrophobic. The modified porous AAM demonstrated over 99% separation efficiency when treating 30 L of model water containing 5 mg/L of polyethylene microspheres (53-63 μm). Its performance was also evaluated in treating laundry effluent, where the modified porous AAM achieved approximately 84% separation compared to around 52% for the unmodified porous AAM.Abstrakti
Alkaliaktivoiduilla materiaaleilla on runsaasti erilaisia sovelluksia veden ja jäteveden käsittelyssä. Tässä väitöskirjassa valmistettiin huokoisia alkaliaktivoituja vaahtoja tavoitteena selvittää niiden uusia hyödyntämismahdollisuuksia adsorboivina suodatinmateriaaleina, veden desinfioinnissa ja mikromuovin erottamisessa.
Masuunikuonasta valmistettujen adsorboivien suodattimien koostumus optimoitiin muuttamalla valmistuksessa käytetyn pinta-aktiivisen aineen tyyppiä sekä vaahdotinaineena toimivan vetyperoksidin lisäysmäärää. Optimoidulla materiaalilla tutkittiin metyleenisinisen adsorptiota vedestä. Adsorptiokyvyn lisäämiseksi valmistettiin ligniiniä sisältävää komposiittimateriaalia. Dynaamisessa metyleenisinisen adsorptiokokeessa suurin adsorptiomäärä ligniinikomposiitille oli ~40 mg/g. Lisäksi peretikkahappoa tutkittiin vaihtoehtoisena vaahdotusaineena. Peretikkahappoa käytettäessä havaittiin pienempi turpoaminen valmistuksen aikana ja lyhyempi kovettumisaika verrattuna vetyperoksidilla valmistettuihin vaahtoihin.
Tutkimuksen seuraavassa osassa tutkittiin veden desinfiointia. Alkaliaktivoituja vaahtoja valmistettiin metakaoliinista, masuunikuonasta ja niiden seoksista tavoitteena saavuttaa samanlainen veden läpäisevyys kuin keraamisilla suodattimilla. Tämän jälkeen optimoitua vaahtoa käsiteltiin kolloidisella hopealiuoksella ja sen käyttömahdollisuuksia veden desinfioinnissa tutkittiin 10 viikon ajan. Hopeaa sisältävä vaahto osoitti merkittävää E. coli -bakteerien vähenemistä (2,84 log10) verrattuna hopeaa sisältämättömään suodattimeen (1,57 log10). Lisäksi alkaliaktivoidun vaahdon ympäristövaikutuksia analysoitiin elinkaariarvioinnin avulla ja niiden todettiin olevan pienempiä kuin perinteisen keraamin.
Mikromuovien erottamiseksi alkaliaktivoituja vaahtoja käsiteltiin trietoksi(oktyyli)silaanilla superhydrofobisen pinnan luomiseksi. Käsitelty vaahto poisti yli 99 % mikromuovista kokeessa, jossa käsiteltiin 30 litraa vettä, joka sisälsi 5 mg/l polyetyleenipartikkeleita (koko 53–63 μm). Käsitellyn vaahdon suorituskykyä arvioitiin myös pyykinpesuveden käsittelyssä, jossa sen muovin poistokyky oli noin 84 % kun taas ei-käsitelty vaahto poisti vain 52 %
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
Changes in the flood plains and water quality along the Himalayan rivers after the Chamoli disaster of 7 February 2021
No full textThe Himalayan regions are vulnerable to all kinds of natural hazards. On 7 February 2021, a deadly disaster occurred near the Tapovan, in Uttarakhand, Himalayas. During the event, large volume of debris along with broken glacial fragments flooded the Rishi Ganga River and washed away the nearby hydropower plants (Rishi Ganga and Tapovan), which was revealed from detailed analysis of multi spectral and bi-temporal satellite data. We present the impact of the Chamoli disaster on the flood plains and water quality of Himalayan rivers, Rishi Ganga near Tapovan, Alaknanda near Srinagar and Ganga near Haridwar and Bijnor. We used four locations along four sections of Himalayan rivers and have analysed various indices, modified normalized difference water index, normalized difference chlorophyll index, and normalized difference turbidity index, to study the changes in water quality and flood plains. On comparison of the spectral and backscattering coefficients derived from Sentinel-2 optical and Sentinel-1 synthetic aperture radar data, changes in the water quality and flood plains of the rivers were found
Chamoli disaster: pronounced changes in water quality and flood plains using Sentinel data
No full textThe Himalayan rivers are vulnerable to devastating flooding caused by landslides and outbreak of glacial lakes. On 7 February 2021, a deadly disaster occurred near the Rishi Ganga Hydropower Plant in the Rishi Ganga River, killing more than 100 people. During the event, a large volume of debris and broken glacial fragments flooded the Rishi Ganga River and washed away the Rishi Ganga Hydropower plant ongoing project. This study presents the impact of the Chamoli disaster on the water quality of Rishi Ganga River in upstream near Tapovan and Ganga River in downstream near Haridwar through remote sensing data. Five points have been used at different locations across the two study areas and three different indices were used such as Normalized difference water index (NDWI), Normalized difference turbidity Index (NDTI), and Normalized difference chlorophyll index (NDCI), to analyze changes in water quality. Spectral signatures and backscattering coefficients derived from Sentinel-2 Optical and Sentinel-1 Synthetic-aperture radar (SAR) data were also compared to study the changes in water quality. It was evident from the water quality indices and spectral signatures that the flood plains changed significantly. Using spectral signatures and different indices, the water level in the Chilla dam canal near Haridwar was found to decreased after the Chamoli disaster event as the flood gates were closed to stop the deposit of sediments in the canal. Results suggest changes in water quality parameters (turbidity, chlorophyll concentration, NDWI) at the five locations near the deadly site and far away at Haridwar along the Ganga River. This study is a preliminary qualitative analysis showing changes in river flood plain and water quality after the Chamoli disaster
Snow covered with dust after Chamoli rockslide: inference based on high-resolution satellite data
No full textThe high-resolution multi-temporal PlanetScope image of 7 February 2021 clearly shows the fall of a large part of the Nanda Ghunti glacier (Uttarakhand) down in the base of the valley from a height of about 2000 m. The recorded seismic signals at the local seismic networks, close to the Joshimath station, show the occurrence of the fall of the first glacier block followed by another block which corresponds to the seismic signal recorded the second time. The timings of signals recorded from the seismic station are related to the visual sign of local dust in the valley after the fall of the glacier blocks at 05:01 AM and 05:28 AM UTC on 7 February 2021. In the present paper, we carried out the changes in spectral signatures of PlanetScope imageries and backscattering coefficients from Sentinel-1 synthetic aperture radar (SAR) data at six different locations. Our analysis suggests pronounced changes at all locations based on spectral signatures and backscattering coefficients due to deposition of snow dust due to the fall of the glacier blocks. Changes in surface wetness are evident after the melting of snow due to the deposition of dust in the valley
"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.
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
Aortic root replacement using tissue prosthesis: Early results of the initial five cases with biovalsalva graft
No full text2012 Poster Presentation/Panel 30Takahiro Sawada, Michael Worthington, Robert Xu, Jason Varzaly, Kan Nawata, Ritwick Bhuyan, Krishanu Chaudhuri, James Edwards, Robert Stukli
Mapping and characterising buildings for flood exposure analysis using open-source data and artificial intelligence
No full textThe mapping and characterisation of building footprints is a challenging task due to inaccessibility and incompleteness of the required data, thus hindering the estimation of loss caused by natural and anthropogenic hazards. Major advancements have been made in the collaborative mapping of buildings with platforms like OpenStreetMap, however, many parts of the world still lack this information or the information is outdated. We created a semi-automated workflow for the development of elements-at-risk (EaR) databases of buildings by detecting building footprints using deep learning and characterising the footprints with building occupancy information using building morphological metrics and open-source auxiliary data. The deep learning model was used to detect building EaR footprints in a city in Kerala (India) with an F1 score of over 76%. The footprints were classified into 13 building occupancy types along with information such as average number of floors, total floor space area, building density, and percentage of built-up area. We analysed the transferability of the approach to a different city in Kerala and obtained an almost similar F1 score of 74%. We also examined the exposure of the buildings and the associated occupancies to floods using the 2018 flood susceptibility map of the respective cities. We notice certain shortcomings in our research particularly, the need for a local expert and good quality auxiliary data to obtain reasonable building occupancy information, however, our research contributes to developing a rapid method for generating a building EaR database in data-scarce regions with attributes of occupancy types, thus supporting regional risk assessment, disaster risk mitigation, risk reduction initiatives, and policy developments
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
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