Production of bamboo leaf ash by auto-combustion for pozzolanic and sustainable use in cementitious matrices

[EN] In the context of world concern with the environment, this study aims to characterize an auto combustion produced bamboo leaf ash (BLA) by its pozzolanic behaviour, reactivity and its influence in the total porosity, pore size distribution, tortuosity and mechanical behaviour of cementitious matrices. The chemical and physical characterization of the BLA was carried using X-ray fluorescence, determination of amorphous silica content, X-ray diffraction, Fourier Transform Infrared Spectrophotometry (FTIR), laser granulometry and field emission scanning electron microscopy (FESEM). The assessed BLA is a siliceous material (74.23%) with an amorphous nature due to the amorphous silica content, which represents 92.33% of the total silica. The BLA was classified as highly reactive by assessing its pH and conductivity in a saturated calcium hydroxide (CH) medium for different proportions and temperatures. Frattini analysis, the study of CH:BLA pastes (Thermogravimetric analysis and FTIR) and Portland cement (OPC)/pozzolan pastes (Thermogravimetric analysis and FESEM) are in agreement with this classification. The replacement of OPC by BLA improved the mechanical behaviour of the cementitious matrices, as well their durability. All the mortars containing BLA presented very similar compressive strength to a control mortar (100% OPC) after only 3 days of curing and at the following tested curing ages: 7, 28 and 90 days. In the mercury intrusion porosimetry analysis, the pastes with 20 and 30% BLA content presented higher tortuosity or fewer connected pores than the control paste. Thus, the auto-combustion method proved to be successful and BLA is a suitable alternative for sustainable high-performance matrices. (C) 2019 Elsevier Ltd. All rights reserved.The authors would like to thank São Paulo Research Foundation (FAPESP), grant #2016/16403-5 and #2017/21563-4.Moraes, M.; Moraes, J.; Tashima, M.; Akasaki, J.; Soriano Martinez, L.; Borrachero Rosado, MV.; Paya Bernabeu, JJ. (2019). Production of bamboo leaf ash by auto-combustion for pozzolanic and sustainable use in cementitious matrices. Construction and Building Materials. 208:369-380. https://doi.org/10.1016/j.conbuildmat.2019.03.007S36938020

An architecture for message exchange in pervasive healthcare based on the use of intelligent agents

Aims: This paper proposes an architecture for the exchange of context-aware messages in Pervasive Healthcare environments.\ud \ud Materials and methods: In Pervasive Healthcare, novel information and communication technologies are applied to support the provision of health services anywhere, at anytime, and to anyone. Ubiquitous Computing technologies allow efficient and safe information exchange amongst caregivers and their patients in communities, homes and hospitals. Since health systems may offer their health records in various electronic formats, the openEHR foundation has proposed a dual model to achieve semantic interoperability between such systems. Intelligent Agents is a technology that has been applied to simulate human skills in healthcare procedures. This architecture is based on technologies from Ubiquitous Computing and Intelligent Agents, and complies with the openEHR dual model.\ud \ud Results: This architecture was demonstrated and evaluated in a controlled experiment that we conducted in the cardiology department of a hospital located in the city of Marília (São Paulo, Brazil).\ud \ud Conclusion: An application was developed to evaluate this architecture, and the results showed that the architecture is suitable for facilitating the development of healthcare systems by offering generic resources and powerful solution to integrate these systems

Optimum use of sugar cane straw ash (SCSA) in alkali-activated binders based on blast furnace slag (BFS)

[EN] Alkali-activated binders (AABs) are a material obtained from the combination of a solid precursor and an alkaline activating solution. In this study, one solid precursor used was blast-furnace slag (BFS) and the other was an agro waste: sugar cane straw ash (SCSA). Sodium hydroxide was used for preparing activating solutions. In order to reach the potential reactivity of the SCSA, a study varying the BFS/SCSA mass ratio and H2O=Na2O molar ratio was carried out. The BFS/SCSA ratio varied from 100=0 to 70=30, and H2O=Na2O was studied in the range of 11.1¿18.5. To fulfill this objective, specimens were assessed by their compressive strength of mortars and microstructural studies of pastes [X-ray diffraction (XRD); thermogravimetric analysis (TGA); Fourier transform infrared spectroscopy (FTIR); and field emission scanning electron microscopy (FESEM)] in the curing time range of 3¿90 days at 25°C. Results from these tests showed that the best BFS/SCSA and H2O=Na2O ratios were 70=30 and 18.5, respectively. This study revealed an interesting valorization of the SCSA as a complementary precursor in BFS-based AABs because of the improvement of mechanical properties and the reduction in the consumption of BFS in AABThe authors would like to thank CNPq processo n° 401724/2013-1, CNPq processo n° 140779/2015-0, and the Ministerio de Educación, Cultura y Deporte of Spain ( Cooperación Interuniversitaria program with Brazil PHB-2011-0016-PC). Thanks are also given to the Electron Microscopy Service of the Universitat Politècnica de València.Moraes, J.; Tashima, M.; Melges, J.; Akasaki, J.; Monzó Balbuena, JM.; Borrachero Rosado, MV.; Soriano Martinez, L.... (2018). Optimum use of sugar cane straw ash (SCSA) in alkali-activated binders based on blast furnace slag (BFS). Journal of Materials in Civil Engineering. 30(6):1-12. https://doi.org/10.1061/(ASCE)MT.1943-5533.0002261S11230

New use of sugar cane straw ash in alkali-activated materials: a silica source for the prparation of alkaline activator

[EN] Alkali silicates, expensive and highly pollutant chemical reagents, are required to produce the alkaline activator for high-performance alkali-activated materials. This study presents a new silica source for producing the alkaline activator, sugar cane straw ash (SCSA). An activating suspension was prepared with SCSA and NaOH by means of a thermal bottle. The ash reacting time inside the thermal bottle (s) was assessed from 0 to 48 h, and the SCSA amount in suspension, represented by the SiO2/Na2O ratio (e), was analysed from 0 to 1.82. Compressive strengths were obtained from blast-furnace slag-based mortars that were cured for three days at 65 C, with the optimal mortars produced when s = 24 h and e = 1.46. Comparison of these new SCSA systems with two common silica sources, sodium silicate chemical reagent and rice husk ash, revealed that SCSA yielded lower results than the former and similar results to the latter silica source.The authors would like to thank CNPq processo no 401724/2013-1 and CNPq processo no 140779/2015-0. The authors would also like to thank the Electron Microscopy Service of the Universitat Politecnica de Valencia.Moraes, J.; Font-Pérez, A.; Soriano Martinez, L.; Akasaki, J.; Tashima, M.; Monzó Balbuena, JM.; Borrachero Rosado, MV.... (2018). New use of sugar cane straw ash in alkali-activated materials: a silica source for the prparation of alkaline activator. Construction and Building Materials. 171:611-621. https://doi.org/10.1016/j.conbuildmat.2018.03.230S61162117

Anticardiolipin Antibody In Recurrent Spontaneous Aborting And Fertile Women.

OBJECTIVE: To determine the association between the presence of anticardiolipin antibody and a history of recurrent spontaneous abortion. STUDY DESIGN: Clinical controlled study. LOCATION: Department of Gynecology and Obstetrics-University of Campinas (UNICAMP). SUBJECTS: 52 individuals with recurrent spontaneous abortion were included in Group 1 and 104 individuals with at least one live born child in Group 2. Elapsed time from last delivery to blood sampling varied from six months to two years. METHOD: Between November 1993 and November 1994, patients' blood samples were screened for anticardiolipin antibody by ELISA, as described by Triplett, Barna and Unger (1993). ANALYSIS: Chi-square and Fisher's Exact tests were used for statistical analysis. Student's "t" test was used to compare the means. RESULTS: There was no statistical difference in the presence of the anticardiolipin antibody between Group 1 (zero and 2.9%) and Group 2 (7.7 and 5.8%). CONCLUSION: There was no association between the presence of anticardiolipin antibody and recurrent spontaneous abortion.11641760176

Discussing Quantum Aspects of Higher-Derivative 3D-Gravity in the First-Order Formalism

In this paper, we reassess the issue of deriving the propagators and identifying the spectrum of excitations associated to the vielbein and spin connection of (1+2)-D gravity in the presence of dynamical torsion, while working in the first-order formulation. A number of peculiarities is pointed out whenever the Chern-Simons term is taken into account along with a combination of bilinear terms in the torsion tensor. We present a procedure to derive the full set of propagators, based on an algebra of enlarged spin-type operators, and we discuss under which conditions the poles of the tree-level 2-point functions correspond to physical excitations that do not conflict with causality and unitarity

Graviton Excitations and Lorentz-Violating Gravity with Cosmological Constant

Motivated by the interest raised by the problem of Lorenz-symmetry violating gauge theories in connetion with gravity models, this contribution sets out to provide a general method to systematically study the excitation spectrum of gravity actions which include a Lorentz-symmetry breaking Chern-Simons-type action term for the spin connection. A complete set of spin-type operators is found which accounts for the (Lorentz) violation parameter to all orders and graviton propagators are worked out in a number of different situations

Utilisation of sugar cane straw ash (SCSA) as pozzolan in partially replacement of Portland cement

[ES] La producción de caña de azúcar en Brasil ha aumentado considerablemente en los últimos 10 años. Después del proceso de cosecha mecanizada, se genera un residuo llamado paja de caña de azúcar. Esta paja tiene un buen poder calorífico y puede ser utilizada para generar energía como una biomasa. Sin embargo, después de este proceso de generación de energía se obtiene otro residuo, el cual no tiene un destino adecuado, llamado ceniza de la paja de caña de azúcar (CPC). Una destinación para este residuo es su valorización como un material puzolánico. Para ello, la CPC ha sido caracterizada físicamente y químicamente. La ceniza ha presentado cantidad de sílice amorfa que puede ser utilizada como una puzolana sustituyendo parcialmente el cemento Portland. La reactividad de la ceniza ha sido evaluada por el ensayo de termogravimetría (TGA) en pastas de cal y puzolana. También fueron estudiadas cinco sustituciones del cemento Portland por CPC en morteros: 0 (control), 15, 20, 25 y 30%. En este estudio se prepararon probetas para romper a ensayos de resistencia a compresión en las edades de 3, 7, 28 y 90 días después de un curado a 25 ºC en atmósfera húmeda. Los datos mostraron que la CPC reacciona con la cal y presenta una importante contribución para la resistencia mecánica. Todos los morteros presentaron resistencias a compresión similares después de 90 días de aproximadamente 45 MPa. La conclusión de este trabajo es que esta ceniza CPC puede ser utilizada sustituyendo parcialmente el cemento Portland.[EN] Sugarcane production in Brazil considerably increased in the last 10 years. After the mechanized harvesting, it is generated a waste called by sugar cane straw. This straw presents good calorific value and it can be utilised in energy production as a biomass. However, after the energy generation, it is obtained another waste, which does not have a suitable destination, known as the sugar cane straw ash (SCSA). A destination to this material can be as pozzolanic material. Therefore, the SCSA was physically and chemically characterised. The ash presented amorphous silica that can be used in partial replacement of the Port land cement. The ash reactivity was assessed by thermogravimetric analysis (TGA) of lime/pozzolan pastes. Also five replacement percentages of the Portland cement by SCSA in mortars were evaluated: 0 (control), 15, 20, 25 and 30%. Specimens were moulded in order to be assessed by compressive strength after 3, 7, 28 and 90 days of curing at 25 ºC. All mortars presented similar compressive strength after 90 days of curing of approximately 45 MPa. It can be concluded that the SCSA can be used in partial replac ement of the Portland cement.Los autores desean agradecer al CNPq Brasil por la beca del primer autor, J.C.B. Moraes (proceso 153164/2016-6), y al proceso 401724/2013-1. También al Ministerio de Educación, Cultura y Deporte de España (Cooperación Interuniversitaria con Brasil, proyecto PHB-2011-0016-PC).Moraes, J.; Akasaki, J.; Tashima, M.; Soriano Martinez, L.; Borrachero Rosado, MV.; Paya Bernabeu, JJ. (2018). Utillizacion de la ceniza de paja de caña de azúcar (CPC) como puzolana en sustituciones parciales del cemento portland. Materiales compuestos. 2(1):6-9. http://hdl.handle.net/10251/147925S692

Behavior of metakaolin-based geopolymers incorporating sewage sludge ash (SSA)

[EN] In recent years, geopolymers have become a widely researched binding material. There are technological and environmental advantages tousing this type of binder instead of Portland cement. In this study, binary systems of geopolymers were produced by using mixtures of metakaolin (MK) ,a well-known aluminosilicate raw material, and a residue from sewage sludge incineration: sewage sludge ash (SSA). This ash was used to partially replace the metakaolin in proportions of 0 20%. The mixtures were activated with alkaline solutions and they were cured by using two different conditions: at room temperature (25 °C) and in a thermal bath (65 °C). The samples were assessed by X-ray diffraction, scanning electron microscopy (pastes) and compressive strength (mortars). The results from these studies showed zeolite formation (faujasite) in geopolymers cured in the thermal bath, which caused a decrease in the compressive strength of the alkali-activated mortars.Replacement of MK with SSA caused a lower reduction in the compressive strength of mortars cured at 65 °C. However, at room temperature, similar mechanical strength was observed for the MK and MK-SSA systems. These results demonstrated that SSA is a suitable mineral precursor for partial replacement of MK in geopolymer production.The authors acknowledge Santander Universidades for the grant to Lucia Reig (program: Becas lberoamerica Jovenes Profesores Investigadores Espana 2014), CAPES (CAPES/DGU no 266/12), CNPq (no. 14/2013 processo 478057/2013-0) Scanning electron microscopy service of FEIS/UNESP and CNPq (processo 309015/2015-4).Istuque, D.; Reig Cerdá, L.; Moraes, J.; Akasaki, JL.; Borrachero Rosado, MV.; Soriano Martínez, L.; Paya Bernabeu, JJ.... (2016). Behavior of metakaolin-based geopolymers incorporating sewage sludge ash (SSA). Materials Letters. 180:192-195. https://doi.org/10.1016/j.matlet.2016.05.137S19219518