3,057 research outputs found
A panoramic view of motherhood by juxtaposing the select trilogies of Flora Nwapa and Perumal Murugan
No full text<p>This article by Vimala Johnshi Rani compares the portrayal of motherhood in the works of African writer Flora Nwapa and Indian writer Perumal Murugan. By examining trilogies by each author, Rani explores how women in post-colonial South Africa and India navigate societal expectations and personal desires.</p>
Ammonium removal and recovery from wastewater with porous geopolymers
No full textAbstract
Porous geopolymer granules are emerging as a promising material for high-value applications such as adsorption and ammonium (NH₄⁺) recovery from wastewater. This thesis presents a comprehensive investigation into the fabrication, characterization, and application of porous metakaolin-based geopolymer granules produced via direct foaming, one-part alkali activation, and high-shear granulation. Porosity was introduced using either hydrogen peroxide (H₂O₂) or municipal solid waste incineration fly ash containing metallic aluminum (Al0) as blowing agents. Increased porosity, particularly in the micro- and nanoscale range, significantly enhanced the specific surface area and NH₄⁺ adsorption capacity—up to 126% higher compared to nonporous granules, with optimal performance observed using 10% H₂O₂ solution. The granules demonstrated sufficient mechanical strength (≥2 MPa) and were evaluated for environmental safety and ion-exchange behavior. While fly ash improved porosity, it introduced leaching concerns for elements like antimony and vanadium, limiting its optimal content to 0.3 wt.% Al0. Adsorption-desorption studies showed that porous geopolymer granules achieved an average NH₄⁺ uptake capacity of up to 9.0 mg/g, and NH₄⁺ recovery of 51–98% over the 30 adsorption and desorption cycles using KNO₃ as a regenerant, though performance declined after 20 cycles. Application in municipal wastewater highlighted the need for pretreatment to mitigate pore blocking and surface fouling. Overall, these findings establish porous geopolymer granules as a feasible, regenerable, and effective material for NH₄⁺ recovery, contributing to circular nitrogen economy and sustainable wastewater treatment strategies. Original papers Yu, Y., Perumal, P., Corfe, I. J., Paul, T., Illikainen, M., & Luukkonen, T. (2023). Combined granulation–alkali activation–direct foaming process: A novel route to porous geopolymer granules with enhanced adsorption properties. Materials & Design, 227, 111781. https://doi.org/10.1016/j.matdes.2023.111781 https://doi.org/10.1016/j.matdes.2023.111781 Self-archived version Luukkonen, T., Yu, Y., Adhikary, S. K., Kauppinen, S., Finnilä, M., & Perumal, P. (2024). Metallic aluminium in municipal solid waste incineration fly ash as a blowing agent for porous alkali-activated granules. Royal Society Open Science, 11(8), 240598. https://doi.org/10.1098/rsos.240598 https://doi.org/10.1098/rsos.240598 Self-archived version Yu, Y., Perumal, P., Sithole, T., & Luukkonen, T. (2025). Recovery of ammonium and nitrate from wastewater using adsorption-based techniques: A review. Journal of Cleaner Production, 519, 145976. https://doi.org/10.1016/j.jclepro.2025.145976 https://doi.org/10.1016/j.jclepro.2025.145976 Self-archived version Yu, Y., Bhuyan, M., Perumal, P., Luukkonen, T. (2025). Ammonium removal and recovery from municipal wastewater by ion exchange using porous metakaolin geopolymer granules. Manuscript submitted for publication. Tiivistelmä
Huokoiset geopolymeerirakeet ovat nousemassa lupaavaksi materiaaliksi korkean lisäarvon sovelluksiin, kuten adsorptioon ja ammoniumin (NH₄⁺) talteenottoon jätevedestä. Tämä väitöskirja esittelee kattavan tutkimuksen metakaoliinipohjaisten huokoisten geopolymeerirakeiden valmistuksesta, karakterisoinnista ja käytöstä hyödyntäen vaahdotusta, alkaliaktivointia sekä granulointia. Huokoisuutta lisättiin käyttämällä vaahdotusaineina joko vetyperoksidia (H₂O₂) tai yhdyskuntajätteenpolton lentotuhkaa, joka sisälsi metallista alumiinia (Al0). Huokoisuuden lisääntyminen, erityisesti mikro- ja nanokokoluokissa, paransi merkittävästi rakeiden ominaispinta-alaa ja NH₄⁺-adsorptiokapasiteettia – jopa 126 % verrattuna ei-huokoisiin rakeisiin. Paras suorituskyky saavutettiin 10 % H₂O₂-liuoksella. Rakeet osoittivat riittävää mekaanista lujuutta (≥2 MPa), ja niitä arvioitiin myös ioninvaihtokyvyn osalta. Vaikka lentotuhka lisäsi huokoisuutta, se aiheutti haitallisten aineiden, kuten antimonin ja vanadiinin, liukenemista, minkä vuoksi optimaalinen tuhkapitoisuus rajoitettiin 0.3 paino-% Al0:aan. Adsorptio-desorptiotutkimukset osoittivat, että huokoiset geopolymeerirakeet saavuttivat keskimääräisen NH₄⁺-ottokapasiteetin jopa 9.0 mg/g ja NH₄⁺-saannon 51–98 % 30 adsorptio- ja desorptiosyklin aikana, kun KNO3 20:a regeneroivana aineena käytettiin, vaikka suorituskyky heikkeni syklin jälkeen. Pitkän aikavälin käytössä suorituskyky kuitenkin heikkeni. Kunnallisen jäteveden käsittelyssä havaittiin huokosten tukkeutumista ja pintaan kertyvää kiintoainesta, mikä korostaa esikäsittelyn merkitystä. Yhteenvetona voidaan todeta, että huokoiset geopolymeerirakeet ovat käyttökelpoinen, uudelleenkäytettävä ja tehokas materiaali NH₄⁺:n talteenottoon, edistäen typen kiertotaloutta ja kestävää jäteveden käsittelyä. Osajulkaisut Yu, Y., Perumal, P., Corfe, I. J., Paul, T., Illikainen, M., & Luukkonen, T. (2023). Combined granulation–alkali activation–direct foaming process: A novel route to porous geopolymer granules with enhanced adsorption properties. Materials & Design, 227, 111781. https://doi.org/10.1016/j.matdes.2023.111781 https://doi.org/10.1016/j.matdes.2023.111781 Rinnakkaistallennettu versio Luukkonen, T., Yu, Y., Adhikary, S. K., Kauppinen, S., Finnilä, M., & Perumal, P. (2024). Metallic aluminium in municipal solid waste incineration fly ash as a blowing agent for porous alkali-activated granules. Royal Society Open Science, 11(8), 240598. https://doi.org/10.1098/rsos.240598 https://doi.org/10.1098/rsos.240598 Rinnakkaistallennettu versio Yu, Y., Perumal, P., Sithole, T., & Luukkonen, T. (2025). Recovery of ammonium and nitrate from wastewater using adsorption-based techniques: A review. Journal of Cleaner Production, 519, 145976. https://doi.org/10.1016/j.jclepro.2025.145976 https://doi.org/10.1016/j.jclepro.2025.145976 Rinnakkaistallennettu versio Yu, Y., Bhuyan, M., Perumal, P., Luukkonen, T. (2025). Ammonium removal and recovery from municipal wastewater by ion exchange using porous metakaolin geopolymer granules. 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 Oulun Puhelin auditorium (L5), Linnanmaa, on 10 October 2025, at 12 noonAbstract
Porous geopolymer granules are emerging as a promising material for high-value applications such as adsorption and ammonium (NH₄⁺) recovery from wastewater. This thesis presents a comprehensive investigation into the fabrication, characterization, and application of porous metakaolin-based geopolymer granules produced via direct foaming, one-part alkali activation, and high-shear granulation. Porosity was introduced using either hydrogen peroxide (H₂O₂) or municipal solid waste incineration fly ash containing metallic aluminum (Al0) as blowing agents. Increased porosity, particularly in the micro- and nanoscale range, significantly enhanced the specific surface area and NH₄⁺ adsorption capacity—up to 126% higher compared to nonporous granules, with optimal performance observed using 10% H₂O₂ solution. The granules demonstrated sufficient mechanical strength (≥2 MPa) and were evaluated for environmental safety and ion-exchange behavior. While fly ash improved porosity, it introduced leaching concerns for elements like antimony and vanadium, limiting its optimal content to 0.3 wt.% Al0. Adsorption-desorption studies showed that porous geopolymer granules achieved an average NH₄⁺ uptake capacity of up to 9.0 mg/g, and NH₄⁺ recovery of 51–98% over the 30 adsorption and desorption cycles using KNO₃ as a regenerant, though performance declined after 20 cycles. Application in municipal wastewater highlighted the need for pretreatment to mitigate pore blocking and surface fouling. Overall, these findings establish porous geopolymer granules as a feasible, regenerable, and effective material for NH₄⁺ recovery, contributing to circular nitrogen economy and sustainable wastewater treatment strategies.Tiivistelmä
Huokoiset geopolymeerirakeet ovat nousemassa lupaavaksi materiaaliksi korkean lisäarvon sovelluksiin, kuten adsorptioon ja ammoniumin (NH₄⁺) talteenottoon jätevedestä. Tämä väitöskirja esittelee kattavan tutkimuksen metakaoliinipohjaisten huokoisten geopolymeerirakeiden valmistuksesta, karakterisoinnista ja käytöstä hyödyntäen vaahdotusta, alkaliaktivointia sekä granulointia. Huokoisuutta lisättiin käyttämällä vaahdotusaineina joko vetyperoksidia (H₂O₂) tai yhdyskuntajätteenpolton lentotuhkaa, joka sisälsi metallista alumiinia (Al0). Huokoisuuden lisääntyminen, erityisesti mikro- ja nanokokoluokissa, paransi merkittävästi rakeiden ominaispinta-alaa ja NH₄⁺-adsorptiokapasiteettia – jopa 126 % verrattuna ei-huokoisiin rakeisiin. Paras suorituskyky saavutettiin 10 % H₂O₂-liuoksella. Rakeet osoittivat riittävää mekaanista lujuutta (≥2 MPa), ja niitä arvioitiin myös ioninvaihtokyvyn osalta. Vaikka lentotuhka lisäsi huokoisuutta, se aiheutti haitallisten aineiden, kuten antimonin ja vanadiinin, liukenemista, minkä vuoksi optimaalinen tuhkapitoisuus rajoitettiin 0.3 paino-% Al0:aan. Adsorptio-desorptiotutkimukset osoittivat, että huokoiset geopolymeerirakeet saavuttivat keskimääräisen NH₄⁺-ottokapasiteetin jopa 9.0 mg/g ja NH₄⁺-saannon 51–98 % 30 adsorptio- ja desorptiosyklin aikana, kun KNO3 20:a regeneroivana aineena käytettiin, vaikka suorituskyky heikkeni syklin jälkeen. Pitkän aikavälin käytössä suorituskyky kuitenkin heikkeni. Kunnallisen jäteveden käsittelyssä havaittiin huokosten tukkeutumista ja pintaan kertyvää kiintoainesta, mikä korostaa esikäsittelyn merkitystä. Yhteenvetona voidaan todeta, että huokoiset geopolymeerirakeet ovat käyttökelpoinen, uudelleenkäytettävä ja tehokas materiaali NH₄⁺:n talteenottoon, edistäen typen kiertotaloutta ja kestävää jäteveden käsittelyä
Recycling and reusing of waste concrete fines as granulated aggregates
No full textAbstract
In recent years, a large amount of construction and demolition waste has been generated by many demolition and construction projects because of fast urbanization. There is therefore a growing need for the sustainable management of construction waste and its recycling. The fine fraction of construction waste is especially challenging to reuse, and the problem is that it is yet to be fully utilized.
Current options for the recycling of recycled concrete fines are limited, and there is a lack of research related to this. Today, recycled concrete fines are typically dumped in landfill, which requires large areas and may cause environmental contamination through water and soil pollution. The recycling and utilization of recycled concrete fines could make a significant contribution to sustainable development and the environment.
This thesis, examined the possibility of the utilization of the recycled concrete fines. The general aim was to produce artificial aggregates from different recycled concrete fines by granulation.
The results of this thesis show that with suitable co-binders and curing methods, it is possible to produce artificial aggregates from recycled concrete fines that have comparable engineering properties as commercial lightweight aggregates.
Most of the produced artificial aggregates can be classified as lightweight aggregates according to the EN 13055-1 standard. It was observed that the strength of the produced aggregates was highly dependent on their reactivity, particle size, and the different co-binders and curing methods used. The lightweight concrete produced from these artificial aggregates showed almost similar strength to lightweight concrete produced from commercial lightweight aggregate. Original papers Kursula, K., Perumal, P., Ohenoja, K., & Illikainen, M. (2022). Production of artificial aggregates by granulation and carbonation of recycled concrete fines. Journal of Material Cycles and Waste Management, 24(6), 2141–2150. https://doi.org/10.1007/s10163-022-01457-y https://doi.org/10.1007/s10163-022-01457-y Self-archived version Moukannaa, S., Kursula, K., Perumal, P., Ohenoja, K., & Illikainen, M. (2022). Recycling of precast concrete waste sludge with paper mill and biomass ashes for lightweight granulated aggregate production. Frontiers in Materials, 9, 877160. https://doi.org/10.3389/fmats.2022.877160 https://doi.org/10.3389/fmats.2022.877160 Self-archived version Kursula, K., Illikainen, M., & Perumal, P. (2023). Recycling alkali activated slag into artificial aggregate: Influence of particle size distribution of the starting material on granulation. Low-Carbon Materials and Green Construction, 1(1), 28. https://doi.org/10.1007/s44242-023-00031-5 https://doi.org/10.1007/s44242-023-00031-5 Self-archived version Kursula, K., Mistri, A., Illikainen, M., & Perumal, P. (2024). Utilization of fine concrete waste as a lightweight aggregate via granulation: Technical and environmental assessment. Journal of Cleaner Production, 434, 139938. https://doi.org/10.1016/j.jclepro.2023.139938 https://doi.org/10.1016/j.jclepro.2023.139938 Self-archived version Tiivistelmä
Kaupungistuminen on johtanut viime vuosina moniin rakennus- ja purkuprojekteihin, joka on tuottanut valtavan määrän erilaista rakennus- ja purkujätettä. Näin ollen rakennus- ja purkujätteen kierrättämiselle ja ympäristöystävälliselle uudelleenkäytölle on kasvavaa kysyntää. Erityisesti betonijätteestä syntyvä hienoaines on haastavaa kierrättää ja ongelmana on, ettei sitä pystytä täysin hyödyntämään.
Nykyiset vaihtoehdot jätebetonijauheen kierrättämiselle ovat vähäiset ja tutkimusta sen hyödyntämisestä on tehty vähän. Yleensä jätebetonin hienoaine on viety kaatopaikalle, mikä vaatii suuria maapinta-aloja ja on ympäristölle haitallista sillä se saattaa saastuttaa maaperää ja luonnonvesiä. Näin ollen jätebetonijauheen hyödyntämisellä olisi suuria etuja kestävän kehityksen ja ympäristön kannalta.
Tässä väitöskirjassa tarkoituksena on tutkia jätebetonin hienoaineksen hyödyntämismahdollisuuksia. Erityinen tavoite oli tuottaa aggregaatteja erilaisista jätebetonijauheista rakeistusprosessin avulla.
Väitöskirjan tulokset osoittavat, että sopivien sideaineiden ja kovetusmenetelmien avulla on mahdollista tuottaa jätebetonijauheesta aggregaatteja, joilla on vertailukelpoiset ominaisuudet kaupallisen kevytsoran kanssa.
Suurin osa tuotetuista aggregaateista voidaan luokitella kevytsoraksi standardin EN 13055-1 mukaan. Tutkimuksessa havaittiin, että tuotettujen aggregaattien lujuus riippui suuresti käytetyn betonijauheen reaktiivisuudesta ja partikkelikoosta, sekä käytetystä sideaineesta ja kovetusmenetelmästä. Näillä aggregaateilla valmistettujen kevytbetonien lujuus oli vertailukelpoinen kaupallisella kevytsoralla valmistettuun betoniin. Osajulkaisut Kursula, K., Perumal, P., Ohenoja, K., & Illikainen, M. (2022). Production of artificial aggregates by granulation and carbonation of recycled concrete fines. Journal of Material Cycles and Waste Management, 24(6), 2141–2150. https://doi.org/10.1007/s10163-022-01457-y https://doi.org/10.1007/s10163-022-01457-y Rinnakkaistallennettu versio Moukannaa, S., Kursula, K., Perumal, P., Ohenoja, K., & Illikainen, M. (2022). Recycling of precast concrete waste sludge with paper mill and biomass ashes for lightweight granulated aggregate production. Frontiers in Materials, 9, 877160. https://doi.org/10.3389/fmats.2022.877160 https://doi.org/10.3389/fmats.2022.877160 Rinnakkaistallennettu versio Kursula, K., Illikainen, M., & Perumal, P. (2023). Recycling alkali activated slag into artificial aggregate: Influence of particle size distribution of the starting material on granulation. Low-Carbon Materials and Green Construction, 1(1), 28. https://doi.org/10.1007/s44242-023-00031-5 https://doi.org/10.1007/s44242-023-00031-5 Rinnakkaistallennettu versio Kursula, K., Mistri, A., Illikainen, M., & Perumal, P. (2024). Utilization of fine concrete waste as a lightweight aggregate via granulation: Technical and environmental assessment. Journal of Cleaner Production, 434, 139938. https://doi.org/10.1016/j.jclepro.2023.139938 https://doi.org/10.1016/j.jclepro.2023.139938 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 12 April 2024, at 12 noonAbstract
In recent years, a large amount of construction and demolition waste has been generated by many demolition and construction projects because of fast urbanization. There is therefore a growing need for the sustainable management of construction waste and its recycling. The fine fraction of construction waste is especially challenging to reuse, and the problem is that it is yet to be fully utilized.
Current options for the recycling of recycled concrete fines are limited, and there is a lack of research related to this. Today, recycled concrete fines are typically dumped in landfill, which requires large areas and may cause environmental contamination through water and soil pollution. The recycling and utilization of recycled concrete fines could make a significant contribution to sustainable development and the environment.
This thesis, examined the possibility of the utilization of the recycled concrete fines. The general aim was to produce artificial aggregates from different recycled concrete fines by granulation.
The results of this thesis show that with suitable co-binders and curing methods, it is possible to produce artificial aggregates from recycled concrete fines that have comparable engineering properties as commercial lightweight aggregates.
Most of the produced artificial aggregates can be classified as lightweight aggregates according to the EN 13055-1 standard. It was observed that the strength of the produced aggregates was highly dependent on their reactivity, particle size, and the different co-binders and curing methods used. The lightweight concrete produced from these artificial aggregates showed almost similar strength to lightweight concrete produced from commercial lightweight aggregate.Tiivistelmä
Kaupungistuminen on johtanut viime vuosina moniin rakennus- ja purkuprojekteihin, joka on tuottanut valtavan määrän erilaista rakennus- ja purkujätettä. Näin ollen rakennus- ja purkujätteen kierrättämiselle ja ympäristöystävälliselle uudelleenkäytölle on kasvavaa kysyntää. Erityisesti betonijätteestä syntyvä hienoaines on haastavaa kierrättää ja ongelmana on, ettei sitä pystytä täysin hyödyntämään.
Nykyiset vaihtoehdot jätebetonijauheen kierrättämiselle ovat vähäiset ja tutkimusta sen hyödyntämisestä on tehty vähän. Yleensä jätebetonin hienoaine on viety kaatopaikalle, mikä vaatii suuria maapinta-aloja ja on ympäristölle haitallista sillä se saattaa saastuttaa maaperää ja luonnonvesiä. Näin ollen jätebetonijauheen hyödyntämisellä olisi suuria etuja kestävän kehityksen ja ympäristön kannalta.
Tässä väitöskirjassa tarkoituksena on tutkia jätebetonin hienoaineksen hyödyntämismahdollisuuksia. Erityinen tavoite oli tuottaa aggregaatteja erilaisista jätebetonijauheista rakeistusprosessin avulla.
Väitöskirjan tulokset osoittavat, että sopivien sideaineiden ja kovetusmenetelmien avulla on mahdollista tuottaa jätebetonijauheesta aggregaatteja, joilla on vertailukelpoiset ominaisuudet kaupallisen kevytsoran kanssa.
Suurin osa tuotetuista aggregaateista voidaan luokitella kevytsoraksi standardin EN 13055-1 mukaan. Tutkimuksessa havaittiin, että tuotettujen aggregaattien lujuus riippui suuresti käytetyn betonijauheen reaktiivisuudesta ja partikkelikoosta, sekä käytetystä sideaineesta ja kovetusmenetelmästä. Näillä aggregaateilla valmistettujen kevytbetonien lujuus oli vertailukelpoinen kaupallisella kevytsoralla valmistettuun betoniin
Population genomics of pearl millet (Pennisetum glaucum (L.) R. Br.): Comparative analysis of global accessions and Senegalese landraces
No full textCitation: Hu, Z., Mbacké, B., Perumal, R., Guèye, M. C., Sy, O., Bouchet, S., . . . Morris, G. P. (2015). Population genomics of pearl millet (Pennisetum glaucum (L.) R. Br.): Comparative analysis of global accessions and Senegalese landraces. Bmc Genomics. doi:10.1186/s12864-015-2255-0Background: Pearl millet is a staple food for people in arid and semi-arid regions of Africa and South Asia due to its high drought tolerance and nutritional qualities. A better understanding of the genomic diversity and population structure of pearl millet germplasm is needed to support germplasm conservation and genetic improvement of this crop. Here we characterized two pearl millet diversity panels, (i) a set of global accessions from Africa, Asia, and the America, and (ii) a collection of landraces from multiple agro-ecological zones in Senegal. Results: We identified 83,875 single nucleotide polymorphisms (SNPs) in 500 pearl millet accessions, comprised of 252 global accessions and 248 Senegalese landraces, using genotyping by sequencing (GBS) of PstI-MspI reduced representation libraries. We used these SNPs to characterize genomic diversity and population structure among the accessions. The Senegalese landraces had the highest levels of genetic diversity (?), while accessions from southern Africa and Asia showed lower diversity levels. Principal component analyses and ancestry estimation indicated clear population structure between the Senegalese landraces and the global accessions, and among countries in the global accessions. In contrast, little population structure was observed across in the Senegalese landraces collections. We ordered SNPs on the pearl millet genetic map and observed much faster linkage disequilibrium (LD) decay in Senegalese landraces compared to global accessions. A comparison of pearl millet GBS linkage map with the foxtail millet (Setaria italica) and sorghum (Sorghum bicolor) genomes indicated extensive regions of synteny, as well as some large-scale rearrangements in the pearl millet lineage. Conclusions: We identified 83,875 SNPs as a genomic resource for pearl millet improvement. The high genetic diversity in Senegal relative to other regions of Africa and Asia supports a West African origin of this crop, followed by wide diffusion. The rapid LD decay and lack of confounding population structure along agro-ecological zones in Senegalese pearl millet will facilitate future association mapping studies. Comparative population genomics will provide insights into panicoid crop evolution and support improvement of these climate-resilient crops. © 2015 Hu et al
Female educators leading socio-economically disadvantaged primary schools in post-apartheid South Africa
No full textM.Ed. (Education Management)Abstract: This study was part of the SANPAD (South African Netherlands Partnership for Alternatives in Development) research project with the title for the project “Women leading in disadvantaged education contexts” (Perumal, 2015, p. 70). This study aligned itself with the overall aim and sought to answer the research question: ‘How do female leaders navigate the challenges of leading in poor schools in post-apartheid South Africa?’ It is important to note that education under apartheid was characterized by inequalities that had an impact not only on the teaching and learning of learners but also on the management and leadership of schools (Morrow, 1990, p.174). The legacy of this system was still apparent in post-apartheid South Africa, where governance was the responsibility of the School Governing Body (SGB), and where more females were being appointed in leadership positions at schools (RSA, 1996, pp. 9-10). The experiences of white Afrikaans-speaking female leaders in managing and leading these schools under difficult socio-economic circumstances, and the role that they played in alleviating the effect of poverty on the learners were explored. Research was conducted at three schools in the Gauteng Province of South Africa. In the three cities, the men were the principals and the school management team (SMT) members were women. Semi-structured, individual interviews were used, to obtain data from the participants. During the data analysis, the following themes emerged: the socio-economic context of poverty, living conditions, food insecurity, school experiences, and female leadership strategies. Education budgets were designed to meet equitable outcomes and overcome racial disparities (Chisholm, 2004, p.1), for schools and public services in difficult socio-economic contexts, performed less effectively and local children and families experienced poorer educational outcomes (Naidoo & Perumal, 2014, p.65). In order to ensure that learners in difficult socio-economic conditions performed effectively and experienced improved educational outcomes, the focus had to be on social justice. Female leadership that recognized the unequal circumstances of marginalized groups could therefore direct its actions towards eliminating inequalities and marginalization (DeMatthews & Mawhinney, 2014, p. 846). Naidoo and Perumal (2014, p. 2) stated that..
High strength fiber reinforced one-part alkali activated slag composites from industrial side streams
No full textThis paper details the effect of fiber reinforcement on mechanical characteristics of by-products based one-part
alkali activated material (AAM). Two different binder matrices were considered in this study, such as, plain slag,
and ternary blended slag, to understand their efficiency in fiber reinforced system. These matrices were reinforced
with 1% v/v of three different fibers (steel, glass and basalt) to improve the flexural performance of high
strength mortar blends. Steel fiber reinforced one-part AAM outperforms mineral fibers in compressive strength
contribution. The fracture energy of steel fiber reinforced compositions was roughly 4 times higher than that of
mineral fiber reinforced materials. In addition, the flexural performance of ternary blended matrix was higher
than that of slag-based composition regardless fiber types and properties. Finally, preliminary finite element
modelling was considered to assess the applicability of the concrete damage plasticity constitutive model in
predicting the nonlinear behavior of the developed composites. The numerical predictions proved the accuracy of
the model with good agreement between experimental and numerical results
sj-docx-1-trr-10.1177_03611981231157727 – Supplemental material for Developing Safety Performance Functions and Crash Modification Factors for Urban Roundabouts in Heterogeneous Non-Lane-Based Traffic Conditions
No full textSupplemental material, sj-docx-1-trr-10.1177_03611981231157727 for Developing Safety Performance Functions and Crash Modification Factors for Urban Roundabouts in Heterogeneous Non-Lane-Based Traffic Conditions by V S Vinayaraj and Vedagiri Perumal in Transportation Research Record</p
Melatonin
No full textMelatonin, originally discovered as a hormone of the pineal gland, is produced by bacteria, protozoa, plants, fungi, invertebrates, and various extrapineal sites of vertebrates, including out, skin, Harderian gland, and leukocytes. Biosynthetic pathways seem to be identical. Actions are pleiotropic, mediated by membrane and nuclear receptors, other binding sites or chemical interactions. Melatonin regulates the sleep/wake cycle, other circadian and seasonal rhythms, and acts as an immunostimulator and cytoprotective agent. Circulating melatonin is mostly 6-hydroxylated by hepatic P-450 monooxygenases and excreted as 6-sulfatoxymelatonin. Pyrrole-ring cleavage is of higher importance in other tissues, especially the brain. The product, N-1-acetyl-N-2-formyl-5-methoxykynuramine, is formed by enzymatic, pseudoenzymatic, photocatalytic, and numerous free-radical reactions. Additional metabolites result from hydroxylation and nitrosation. The secondary metabolite, N-1-acetyl-5-methoxykynuramine, supports mitochondrial function and downregulates cyclooxygenase 2. Antioxidative protection, safeguarding of mitochondrial electron flux, and in particular, neuroprotection, have been demonstrated in many experimental systems. Findings are encouraging to use melatonin as a sleep promoter and in preventing progression of neurodegenerative diseases. (C) 2005 Elsevier Ltd. All rights reserved
HYDROGEOCHEMICAL QUALITY OF GROUNDWATER IN PERUMAL LAKE, KURINJIPADI TALUK, CUDDALORE DISTRICT, TAMILNADU, INDIA
No full textA study was carried out to determine the groundwater quality in parts of Perumal Lake, Kurinjipadi Taluk, Cuddalore district, Tamilnadu. Totally, 12 groundwater samples were collected at different parts of study area and 16 water samples from surface reservoirs (Perumal lake) and analyzed for physicochemical parameters (pH, EC, TDS, TH, Na, K, Ca, Mg and Cl, SO4 , HCO3- , NO3 ) in order to understand the hydro geochemistry of the water. The results of analysis were interpreted with geology and geomorphology of the area and also by various geochemical diagrams such as Piper trilinear plot and USSL classification diagram. Suitability of this water for its utility was verified using Indian standards. The result indicates irrespective of the seasons that only one well is suitable for drinking purpose, with remaining suitable for domestic and irrigation purpose. Further, from the results, it is pointed out that most of the well water falls in Na-Cl type indicating the influence of seawater in these wells which was confirmed by Piper plot. According to SAR (alkali hazard) and specific conductance (Salinity hazard) is plotted in USSL diagram, classification of water for irrigation purpose can be determined. Majority of groundwater samples fall in C3S1 zone indicating high salinity and low sodium hazard, satisfactory for plants having moderate salt tolerance on soils. In surface water most of the samples fall in C2S1 indicates medium salinity and low sodium hazard
sj-zip-1-pih-10.1177_09544119221123431 – Supplemental material for An AI based digital-twin for prioritising pneumonia patient treatment
No full textSupplemental material, sj-zip-1-pih-10.1177_09544119221123431 for An AI based digital-twin for prioritising pneumonia patient treatment by Neeraj Kavan Chakshu and Perumal Nithiarasu in Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine</p
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