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Journal ArticleDOI: 10.1080/15583058.2019.1623341

Identification of Bio-Minerals and Their Origin in Lime Mortars of Ancient Monument: Thanjavur Palace

04 Mar 2021-International Journal of Architectural Heritage (Informa UK Limited)-Vol. 15, Iss: 3, pp 426-436
Abstract: The role of organics in ancient mortars of Thanjavur palace was characterized through wet chemical analysis, biochemical tests and sophisticated techniques (XRD, FESEM, FT-IR). All the analytical t...

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8 results found

Journal ArticleDOI: 10.1016/J.JCLEPRO.2020.123682
Abstract: The characterization of limecrete slabs made of plant extract and hemp fibers of an old monument, Bichili haveli, located in Udaipur, Rajasthan, India was carried out to understand the traditional materials used and its production. Limecrete of ratio 1: 1: 3 (Lime: brickbats: sand) were produced with hemp fibers to acts as flexural members. The hardened limecrete shows the predominate phases of calcium carbonate such as calcite with other polymorphs (vaterite & aragonite), tobermorite and Calcium alumina-silica hydrates (CASH). The organic analysis has confirmed the presence of biomolecules which are originated by the addition of fermented plant extracts that acts as a natural admixture during the preparation of limecrete slabs. With the help of organic additives, limecrete also acts as a Carbon Capture and Utilization (CCU) unit and sequester 15–20% of atmospheric carbon di oxide (CO2). The current study reclaims the lost old technology which uses low energy-intensive materials like lime, brick powder & bats, plants extracts and hemp fibers at the same time 20% lesser cost than cement concrete. The experimental evidence from the present research proves that the limecrete slabs have enough strength and durability, also acts as CO2 capture materials in mitigating global emissions. Limecrete can be used for the restoration of the heritage building as well as in modern construction for low rise buildings.

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Topics: Lime (53%), Cement (51%)

3 Citations

Open accessJournal ArticleDOI: 10.3390/SU12177181
02 Sep 2020-Sustainability
Abstract: Lightning strikes are prevalent and inevitable natural phenomena that might cause damages during interaction with building structures and, in some cases, culminate in fires. During the last decades, several lightning strikes have caused considerable damages to cultural and heritage buildings. Furthermore, recent studies indicated a plausible connection between climate changes due to global warming and variations in the frequency and intensity of lightning. The evaluation of the structural efficiency and resilience of cultural buildings to global changes and natural risks appears significant in the light of the current scientific debate. This research aims at the assessment of lightning strikes’ effects on ancient heritage binding materials through the characterization of their thermal and electrical conductivity properties. This study focused on the performance evaluation of green and low-cost mortars based on the use of organic additives. Lime samples were reverse engineered by using a mixture of organics (fig, jaggery, black grape, banana, kadukai), which comprises the most common additives used in traditional Indian mortars. The reliability of the organic mixture in enhancing the resilience of masonry to lightning strikes was analyzed by using electromagnetic field simulation.

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Topics: Lightning strike (59%), Lightning (51%)

2 Citations

Journal ArticleDOI: 10.1140/EPJP/S13360-020-00896-6
M. Shivakumar1, Thirumalini Selvaraj1Institutions (1)
Abstract: This research aims at providing the scientific evidence of ancient construction practice and production technology on the use locally available geoearth materials and natural herbs, namely kadukkai (Terminalia Chebula), neelamari (Indigofera tinctoria), hibiscus (Rosa sinensis), palm jaggery (Borassus flabellifer), aloe vera (Aloe barbadenis) as specified in ancient palm leaf texts which were adopted at Padmanabhapuram Palace, India for preparing the traditional lime mortars. Six mortar samples of three different mortar typologies (wall, bedding and floor finish) were taken from the Padmanabhapuram Palace for the study. The sampled mortars were characterized using physiochemical analysis as well as modern analytical techniques including XRD, TG-DTA, FT-IR and FESEM-EDX methods. Different binder-to-aggregate ratios was proportioned for wall plaster (1:3), bedding mortar (1:2) and floor finish (1:1) and was confirmed through acid loss analysis. Wall plaster samples indicated the presence of organic protein and polysaccharide spectral peaks substantiated by FT-IR analysis. Organics have played a significant role in the formation of calcium aluminate silicates and carbonate polymorphs to enhance the crystalline hydrated phases observed through XRD and FESEM analyses. The thermal investigation substantiated that calcite decarbonation mostly occurred between 705 and 730 °C. The results apprised the wide use of hydraulic lime with fine-grained aggregate particles, added with fermented organics to produce an environmentally friendly organic mortar to restore the structure.

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Topics: Hydraulic lime (58%), Lime (56%), Terminalia chebula (56%) ... read more


52 results found

Open accessJournal ArticleDOI: 10.1093/NAR/GKG500
Abstract: The Clustal series of programs are widely used in molecular biology for the multiple alignment of both nucleic acid and protein sequences and for preparing phylogenetic trees. The popularity of the programs depends on a number of factors, including not only the accuracy of the results, but also the robustness, portability and user-friendliness of the programs. New features include NEXUS and FASTA format output, printing range numbers and faster tree calculation. Although, Clustal was originally developed to run on a local computer, numerous Web servers have been set up, notably at the EBI (European Bioinformatics Institute) (http://www.ebi.

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Topics: MUSCLE (67%), FASTA format (56%), Multiple sequence alignment (55%)

5,140 Citations

Journal ArticleDOI: 10.1016/J.CEMCONCOMP.2011.03.012
Virginie Wiktor1, Henk M. Jonkers1Institutions (1)
Abstract: Crack formation is a commonly observed phenomenon in concrete structures. Although micro crack formation hardly affects structural properties of constructions, increased permeability due to micro crack networking may substantially reduce the durability of concrete structures due to risk of ingress of aggressive substances particularly in moist environments. In order to increase the often observed autogenous crack-healing potential of concrete, specific healing agents can be incorporated in the concrete matrix. The aim of this study was to quantify the crack-healing potential of a specific and novel two-component bio-chemical self-healing agent embedded in porous expanded clay particles, which act as reservoir particles and replace part of regular concrete aggregates. Upon crack formation the two-component bio-chemical agent consisting of bacterial spores and calcium lactate are released from the particle by crack ingress water. Subsequent bacterially mediated calcium carbonate formation results in physical closure of micro cracks. Experimental results showed crack-healing of up to 0.46 mm-wide cracks in bacterial concrete but only up to 0.18 mm-wide cracks in control specimens after 100 days submersion in water. That the observed doubling of crack-healing potential was indeed due to metabolic activity of bacteria was supported by oxygen profile measurements which revealed O2 consumption by bacteria-based but not by control specimens. We therefore conclude that this novel bio-chemical self-healing agent shows potential for particularly increasing durability aspects of concrete constructions in wet environments.

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596 Citations

Journal ArticleDOI: 10.1016/S0009-2541(96)00053-8
30 Oct 1996-Chemical Geology
Abstract: Bacteria are very small (∼ 1.5 μm3), but have the largest surface area to volume ratio of any life form. As a result, by providing interfaces for sorption of metal cations, bacteria are efficient scavengers of dilute metals and can concentrate them from the surrounding aqueous environment. This is mainly due to the overall anionic charge of bacterial surfaces imparted by the macromolecules which make up their fabric. Once metal ions have interacted with the electronegative sites on these molecules, they nucleate the formation of fine-grained minerals using anions from the external milieu as counter-ions for additional metal complexation. It is not unusual for bacteria to precipitate an amount of metal equal to, or exceeding, their cellular weight. Diverse mineral types, including hydroxides /oxides, carbonates, sulfates/ sulfides, and phosphates are common and can be in. amorphous or crystalline phases depending on the stage of mineral development. Since bacteria are ubiquitous in the natural environment, they can potentially play a significant role in the development of fine-grain minerals in soils and sediments. It is also possible that their capacity for metal immobilization can be used to counteract the disastrous effects of acid mine leachates.

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304 Citations

Open accessJournal ArticleDOI: 10.1016/J.MICRES.2012.05.002
Abstract: Seven bacterial isolates screened from rhizosphere of common bean growing at Uttarakhand Himalaya showed potential plant growth promoting (PGP) and antagonistic activities. Based on 16S rRNA gene sequence the isolate BPR7 was identified as Bacillus sp. BPR7. The strain BPR7 produced IAA, siderophore, phytase, organic acid, ACC deaminase, cyanogens, lytic enzymes, oxalate oxidase, and solubilized various sources of organic and inorganic phosphates as well as potassium and zinc. Strain BPR7 strongly inhibited the growth of several phytopathogens such as Macrophomina phaseolina, Fusarium oxysporum, F. solani, Sclerotinia sclerotiorum, Rhizoctonia solani and Colletotricum sp. in vitro. Cell-free culture filtrate of strain BPR7 also caused colony growth inhibition of all test pathogens. PGP and antifungal activities of Bacillus sp. BPR7 suggest that it may be exploited as a potential bioinoculant agent for P. vulgaris.

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Topics: Rhizoctonia solani (56%), Macrophomina phaseolina (54%), Fusarium oxysporum (54%) ... read more

297 Citations

Journal ArticleDOI: 10.1016/J.GCA.2006.11.031
Abstract: Myxococcus xanthus, a common soil bacterium, plays an active role in the formation of spheroidal vaterite. Bacterial production of CO2 and NH3 and the transformation of the NH3 to NH4+ and OH−, thus increasing solution pH and carbonate alkalinity, set the physicochemical conditions (high supersaturation) leading to vaterite precipitation in the microenvironment around cells, and directly onto the surface of bacterial cells. In the latter case, fossilization of bacteria occurs. Vaterite crystals formed by aggregation of oriented nanocrystals with c-axis normal to the bacterial cell-wall, or to the core of the spherulite when bacteria were not encapsulated. While preferred orientation of vaterite c-axis appears to be determined by electrostatic affinity (ionotropic effect) between vaterite crystal (0001) planes and the negatively charged functional groups of organic molecules on the bacterium cell-wall or on extracellular polymeric substances (EPS), analysis of the changes in the culture medium chemistry as well as high resolution transmission electron microscopy (HRTEM) observations point to polymorph selection by physicochemical (kinetic) factors (high supersaturation) and stabilization by organics, both connected with bacterial activity. The latter is in agreement with inorganic precipitation of vaterite induced by NH3 and CO2 addition in the protein-rich sterile culture medium. Our results as well as recent studies on vaterite precipitation in the presence of different types of bacteria suggest that bacterially mediated vaterite precipitation is not strain-specific, and could be more common than previously thought.

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Topics: Vaterite (76%)

245 Citations