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  1. Article: Compressive strength, modulus of elasticity and hardness of geopolymeric cement synthetized from non-calcined natural kaolin

    Pelisser, Fernando / Bernardin, Adriano Michael / Michel, Milton Domingos / da Luz, Caroline Angulski

    Journal of cleaner production. 2021 Jan. 20, v. 280

    2021  

    Abstract: In this work, a natural non-calcined kaolin was used for the synthesis of a geopolymeric paste. The effect of the natural kaolin characteristics and the alkaline activator ratio (Na₂O.SiO₂/NaOH) on the mechanical behavior of the resulting geopolymeric ... ...

    Abstract In this work, a natural non-calcined kaolin was used for the synthesis of a geopolymeric paste. The effect of the natural kaolin characteristics and the alkaline activator ratio (Na₂O.SiO₂/NaOH) on the mechanical behavior of the resulting geopolymeric cement was determined. The chemical and mineral composition of the kaolin were determined by XRF and XRD techniques. For the synthesis, sodium silicate and sodium hydroxide were used in molar ratios of Na₂O.SiO₂/NaOH = 1.0, 1.6 and 2.2 and the curing of the samples was performed at 40 °C. The compressive strength of the samples was evaluated at 7 and 28 days of age. The modulus of elasticity and hardness were determined by instrumented nanoindentation. Microstructural analysis (SEM) combined with chemical analysis (EDS) was performed to study the morphology of the geopolymeric cement samples. The results showed that the natural kaolin is 95% amorphous (Rietveld) and shows small particle size (<5 μm, by SEM). The most efficient composition, with Na₂O.SiO₂/NaOH = 2.2 ratio, showed a modulus of elasticity of 10 GPa, hardness of 0.4 GPa and compressive strength of 67 MPa. In the microstructural analysis, the surface of the samples showed some cracks, probably caused by the curing process, and small roughness, but the cured specimens did not show visible flaws. The high strength is due to the chemical composition of the cement, with a SiO₂/Al₂O₃ ratio of 3.5, and due to the degree of amorphism of the natural kaolin, 95%. Therefore, the use of a natural kaolin, without further calcination, reduces costs and environmental impacts in the design of geopolymeric cements.
    Keywords X-ray diffraction ; X-ray fluorescence spectroscopy ; aluminum oxide ; cement ; chemical analysis ; compression strength ; cost effectiveness ; environmental impact ; hardness ; kaolin ; mechanical properties ; mineral content ; modulus of elasticity ; particle size ; roughness ; silica ; sodium hydroxide ; sodium silicate
    Language English
    Dates of publication 2021-0120
    Publishing place Elsevier Ltd
    Document type Article
    ISSN 0959-6526
    DOI 10.1016/j.jclepro.2020.124293
    Database NAL-Catalogue (AGRICOLA)

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  2. Article ; Online: Sports balls as potential SARS-CoV-2 transmission vectors.

    Pelisser, Michel / Thompson, Joe / Majra, Dasha / Youhanna, Sonia / Stebbing, Justin / Davies, Peter

    Public health in practice (Oxford, England)

    2020  Volume 1, Page(s) 100029

    Abstract: Objects passed from one player to another have not been assessed for their ability to transmit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We found that the surface of sport balls, notably a football, tennis ball, golf ball, and cricket ...

    Abstract Objects passed from one player to another have not been assessed for their ability to transmit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We found that the surface of sport balls, notably a football, tennis ball, golf ball, and cricket ball could not harbour inactivated virus when it was swabbed onto the surface, even for 30 ​s. However, when high concentrations of 5000 ​dC/mL and 10,000 ​dC/mL are directly pipetted onto the balls, it could be detected after for short time periods. Sports objects can only harbour inactivated SARS-CoV-2 under specific, directly transferred conditions, but wiping with a dry tissue or moist 'baby wipe' or dropping and rolling the balls removes all detectable viral traces. This has helpful implications to sporting events.
    Language English
    Publishing date 2020-12-22
    Document type Journal Article
    ISSN 2666-5352
    ISSN (online) 2666-5352
    DOI 10.1016/j.puhip.2020.100029
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Sports balls as potential SARS-CoV-2 transmission vectors

    Michel Pelisser / Joe Thompson / Dasha Majra / Sonia Youhanna / Justin Stebbing / Peter Davies

    Public Health in Practice, Vol 1, Iss , Pp 100029- (2020)

    2020  

    Abstract: Objects passed from one player to another have not been assessed for their ability to transmit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We found that the surface of sport balls, notably a football, tennis ball, golf ball, and cricket ...

    Abstract Objects passed from one player to another have not been assessed for their ability to transmit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We found that the surface of sport balls, notably a football, tennis ball, golf ball, and cricket ball could not harbour inactivated virus when it was swabbed onto the surface, even for 30 s. However, when high concentrations of 5000 dC/mL and 10,000 dC/mL are directly pipetted onto the balls, it could be detected after for short time periods. Sports objects can only harbour inactivated SARS-CoV-2 under specific, directly transferred conditions, but wiping with a dry tissue or moist ‘baby wipe’ or dropping and rolling the balls removes all detectable viral traces. This has helpful implications to sporting events.
    Keywords Sports ; SARS-CoV-2 ; COVID-19 ; Transmission ; Cricket ; Football ; Public aspects of medicine ; RA1-1270
    Language English
    Publishing date 2020-11-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Sports balls as potential SARS-CoV-2 transmission vectors

    Pelisser, Michel / Thompson, Joe / Majra, Dasha / Youhanna, Sonia / Stebbing, Justin / Davies, Peter

    Public Health in Practice

    2020  Volume 1, Page(s) 100029

    Keywords covid19
    Language English
    Publisher Elsevier BV
    Publishing country us
    Document type Article ; Online
    ISSN 2666-5352
    DOI 10.1016/j.puhip.2020.100029
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

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  5. Article: Sports balls as potential SARS-CoV-2 transmission vectors

    Pelisser, Michel / Thompson, Joe / Majra, Dasha / Youhanna, Sonia / Stebbing, Justin / Davies, Peter

    Public Health in Practice

    Abstract: Objects passed from one player to another have not been assessed for their ability to transmit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) We found that the surface of sport balls, notably a football, tennis ball, golf ball, and cricket ... ...

    Abstract Objects passed from one player to another have not been assessed for their ability to transmit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) We found that the surface of sport balls, notably a football, tennis ball, golf ball, and cricket ball could not harbour inactivated virus when it was swabbed onto the surface, even for 30 seconds However, when high concentrations of 5,000 dC/mL and 10,000 dC/mL are directly pipetted onto the balls, it could be detected after for short time periods Sports objects can only harbour inactivated SARS-CoV-2 under specific, directly transferred conditions, but wiping with a dry tissue or moist ‘baby wipe’ or dropping and rolling the balls removes all detectable viral traces This has helpful implications to sporting events
    Keywords covid19
    Publisher WHO
    Document type Article
    Note WHO #Covidence: #640341
    Database COVID19

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  6. Article ; Online: An audit of holotranscobalamin ("Active" B12) and methylmalonic acid assays for the assessment of vitamin B12 status: application in a mixed patient population.

    Sobczyńska-Malefora, Agata / Gorska, Renata / Pelisser, Michel / Ruwona, Patricia / Witchlow, Bernie / Harrington, Dominic J

    Clinical biochemistry

    2014  Volume 47, Issue 1-2, Page(s) 82–86

    Abstract: Background: Vitamin B12 insufficiency/deficiency is common in mixed patient populations. However there is no single marker which can reliably diagnose B12 insufficiency/deficiency. Elevated concentrations of methylmalonic acid (MMA) are considered the ... ...

    Abstract Background: Vitamin B12 insufficiency/deficiency is common in mixed patient populations. However there is no single marker which can reliably diagnose B12 insufficiency/deficiency. Elevated concentrations of methylmalonic acid (MMA) are considered the most representative marker of metabolic vitamin B12 insufficiency, but poor assay availability limits clinical utility. Low concentrations of serum vitamin B12 are often used to assess vitamin B12 status but this approach generates a high rate of false negative results. Emerging evidence indicates that holotranscobalamin (holoTC) may be a more reliable indicator of vitamin B12 status.
    Aims and methods: We substituted serum vitamin B12 measurement with holoTC, supported by MMA in patients referred for assessment of vitamin B12 status. A service evaluation was undertaken of the pattern of MMA values obtained for patients with holoTC 25-50 pmol/L (an indeterminate result). MMA cut-offs of 280 and 360 nmol/L were applied for patients ≤ 65 or >65 years respectively.
    Results: A total of 4,175 consecutive patients were investigated and MMA was analysed for 19% of patients. The incidence of elevated MMA was 41% (holoTC, 25-29 pmol/L), 32% (30-34 pmol/L), 33% (35-39 pmol/L), 30% (40-44 pmol/L), and 26% (45-50 pmol/L).
    Conclusions: Our results indicate that in the clinical setting a holoTC between 25 and 50 pmol/L is a poor predictor for the concentration of MMA provided the goal is to identify patients with MMA values above the limits used in the present study. Further studies are needed to evaluate to what extent holoTC <25 and >50 pmol/L reflect circulatory MMA concentrations.
    MeSH term(s) Biomarkers/blood ; Humans ; Methylmalonic Acid/analysis ; Transcobalamins/analysis ; Vitamin B 12/blood
    Chemical Substances Biomarkers ; Transcobalamins ; Methylmalonic Acid (8LL8S712J7) ; Vitamin B 12 (P6YC3EG204)
    Language English
    Publishing date 2014-01
    Publishing country United States
    Document type Journal Article
    ZDB-ID 390372-2
    ISSN 1873-2933 ; 0009-9120
    ISSN (online) 1873-2933
    ISSN 0009-9120
    DOI 10.1016/j.clinbiochem.2013.08.006
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: Effect of porcelain tile polishing residue on geopolymer cement

    Ramos, Giovanny Antonio / Pelisser, Fernando / Paul Gleize, Philippe Jean / Bernardin, Adriano Michael / Michel, Milton Domingos

    Journal of cleaner production. 2018 Aug. 01, v. 191

    2018  

    Abstract: The polishing of ceramic tiles surface produces high amounts of residual sludge, which requires deposition in controlled landfills. However, porcelain tile polishing residue (PPR) can be used as a partial source of aluminosilicate to produce geopolymer ... ...

    Abstract The polishing of ceramic tiles surface produces high amounts of residual sludge, which requires deposition in controlled landfills. However, porcelain tile polishing residue (PPR) can be used as a partial source of aluminosilicate to produce geopolymer cement. Therefore, in this work, a geopolymeric cement based on PPR and metakaolin was developed using sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) as activator solution. A 23+1 factorial design was used with three factors: PPR content (15, 30 and 45 mass % in relation to metakaolin); NaOH (5, 6 and 7 mass %) and Na2SiO3 (48, 50 and 52 mass %). After synthesis, the samples were characterized by mechanical (compressive strength, hardness and dynamic modulus) and structural analyses (XRD and FTIR). The highest compressive strength was 72 MPa, obtained at 28 days (cured at 23 °C) in the composition containing 15% of PPR and 85% metakaolin, corresponding to a chemical composition with 53% SiO2, 25% Al2O3 and 11% Na2O, relation SiO2/Al2O3 = 3.44, and a structure characterized as poly (sialate-disiloxo). The results showed that PPR can be used as an alternative source of raw material to produce geopolymer cement, while contributing to the reuse of an industrial waste.
    Keywords Fourier transform infrared spectroscopy ; X-ray diffraction ; aluminum oxide ; cement ; ceramics ; chemical composition ; compression strength ; hardness ; industrial wastes ; landfills ; polymers ; raw materials ; silica ; sludge ; sodium hydroxide ; sodium silicate ; tiles
    Language English
    Dates of publication 2018-0801
    Size p. 297-303.
    Publishing place Elsevier Ltd
    Document type Article
    ISSN 0959-6526
    DOI 10.1016/j.jclepro.2018.04.236
    Database NAL-Catalogue (AGRICOLA)

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