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Kawasaki, Japan

Abe K.,JDC Corporation
International Biodeterioration and Biodegradation

Fungal contamination (foxing) was detected on a painting stored in an art museum. The internal environments were assessed using a fungal index. The index is a biological climate-parameter, which represents the environmental capacity to allow fungal growth. To determine the index, fungal detectors encapsulating the spores of sensor fungi were placed at the site being examined. The growth response, germination of the spores and hyphal extension, of xerophilic sensor fungi was observed in the storehouse. The values of fungal index predicted propagation of fungi, although dehumidifiers were already in use. Next year, the number of dehumidifiers installed in the storehouse was increased from 3 to 8. After the number of dehumidifiers was increased, the indices were below the detectable limit in the storehouse indicating no fungal contamination will occur. The sensor fungi used in those assessments were five xerophilic and two non-xerophilic strains. In the assessment before countermeasures were taken, Aspergillus penicillioides showed the highest growth response among the sensor fungi in the fungal detector exposed in the room where the contaminated painting was stored. Eurotium herbariorum showed the highest growth response in other rooms. These two strains were selected as the sensor fungi for assessments of museum environments. © 2009 Elsevier Ltd. All rights reserved. Source

Previously, the author proposed a 'fungal index' that quantifies the capacity for fungal growth in a test environment where a device (fungal detector) encapsulating spores of a xerophilic sensor fungus Eurotium herbariorum was placed. It was also found that an extremely xerophilic fungus, Aspergillus penicillioides, was suitable as a sensor fungus at sites with lower relative humidity (RH). In this report, the hydrophilic fungus Alternaria alternata was added to sensor fungi for the determination of the index in extremely humid environments. Measurements of the index and observations of the formation of spores by the sensor fungi were made in stable climates in moisture chambers, under natural conditions in homes, and in bathrooms prepared in an artificial climate chamber. Higher index values and earlier sporulation were obtained at higher RH in stable climates. The hydrophilic Alt. alternata showed the greatest response at 100% and 97.3% RH, the moderately xerophilic Eur. herbariorum, at 94%, 84%, and 75% RH, and the extremely xerophilic Asp. penicillioides, at 71% RH. In homes, the hydrophilic fungus was most active in water-usage areas, and the xerophilic fungi were most active in non-water-usage areas. Sporulation was observed on sensor fungi in fungal detectors placed in rooms where the index exceeded 18ru/week after one-month exposure. Sites where the index exceeded 18ru/week were referred to as damp, where fungal contamination seems to be unavoidable. Evaluations of ventilation systems in bathrooms with extremely humid climates showed typical examples of a countermeasure to fungal contamination. © 2011 John Wiley & Sons A/S. Source

Boulic M.,Massey University | Phipps R.A.,Massey University | Cunningham M.,Building Research Association Of New Zealand | Cleland D.J.,Massey University | And 3 more authors.

The relationship between the use of unflued gas heaters (UGH, N = 14) and heat pump heaters (HP, N = 12) located in the living rooms, and mould growth on the living room and bedroom walls, of 26 New Zealand (NZ) occupied homes was investigated during winter. Two methods were employed to evaluate the potential of mould growth on walls: (i) measurement of daily hyphal growth rate using a fungal detector (encapsulated fungal spores); and (ii) estimation of fungal contamination based on a four level scale visual inspection. The average wall psychrometric conditions were significantly different between the two heater type groups, in both the living rooms and the bedrooms with the UGH user homes being colder and damper than HP user homes. The UGHs were found to be a significant additional source of moisture in the living rooms which dramatically increased the capacity for fungi to grow on wall surfaces. The average daily hyphal growth rates were 4 and 16 times higher in the living rooms and in the bedrooms of the UGH user homes, respectively. Results from both mould detection methods gave good agreement, showing that the use of a fungal detector was an efficient method to predict the potential of mould growth on the inside of the external walls in NZ homes. © 2015 by the authors. Source

Abe K.,JDC Corporation | Murata T.,University of Kitakyushu
International Biodeterioration and Biodegradation

The present study aimed to establish a prevention strategy to protect cultural assets from fungal attack. A fungal index that assesses conditions critical for fungal growth was determined using a fungal detector in the storerooms of historical buildings in Higashiomi area, Japan. The index measurements were repeated after 4 weeks' exposure of the detectors during the seasons when relative humidity outdoors and/or indoors was high. The index values obtained were from below the measurable lower limit to above the upper limit. The prevention strategy proposed was as follows. Each microclimate was categorized into three levels, A, B, or C, depending on the index values, <1.8, 1.8-18 or >18, respectively. If all microclimates in a room maintain level A continuously, the room is considered free of contamination. If some microclimates maintain level B, fungal contamination might occur. If microclimates maintain level C, fungal contamination is unavoidable, and countermeasures should be taken promptly. Finally, fungal indices are measured for evaluation of the countermeasures and for level-A confirmation. The systematic use of fungal indices will provide practically useful information for conservation and must be applicable to IPM (Integrated Pest Management) in museums and libraries. © 2013 Elsevier Ltd. Source

Iijima K.,Japan Atomic Energy Agency | Tomura T.,Inspection Development Co. | Shoji Y.,Japan Atomic Energy Agency | Shoji Y.,JDC Corporation
Applied Clay Science

In the geological disposal system with stable colloidal particles, the influence of the colloidal particles on the migration of radionuclides has to be evaluated. Not only the distribution coefficient, which is a measure for adsorption of radionuclides on colloidal particles, but also the reversibility of adsorption should be determined. In this study, adsorption and desorption of Cs+ ions on colloidal montmorillonite particles were investigated in the wide range of the initial Cs+ concentrations. A rapid, almost linear and reversible adsorption of Cs+ on montmorillonite was observed at basic condition, indicating that the adsorption of Cs+ on montmorillonite was mostly dominated by ion exchange. The size of the montmorillonite particles slightly affected the distribution coefficients at lower Cs+ concentrations, suggesting the contribution of surface complexation. The ion exchange and surface complexation model reproduced the adsorption and desorption behavior of Cs+. To explain the fixation of Cs+, montmorillonite was conditioned with the solutions of various Cs+ concentrations and the basal spacing was measured by X-ray diffraction (XRD). Conditioning montmorillonite at higher Cs+ concentrations >5×10-3M decreased the basal spacing which may result in the fixation of Cs+ in the interlayer space. Since the adsorption experiments were carried out at lower Cs+ concentration <10-4M, Cs+ adsorption was reversible. © 2010 Elsevier B.V. Source

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