Rock Wool Fibers Research Articles

Effects of fiber characteristics on lung deposition, retention, and disease.

There is abundant epidemiologic evidence that asbestos fibers can cause lung fibrosis (asbestosis), bronchial cancer, and mesothelioma in humans, as well as limited evidence for such effects in workers exposed to slag and rockwool fibers. Epidemiological evidence for human disease from inhalation exposures to conventional fibrous glass is negative. While health concerns based on the morphological and toxicological similarities between man-made fibers and asbestos are warranted, it is important to note that most of the toxicological evidence for glass fiber toxicity in laboratory animals is based on nonphysiological exposures such as intratracheal instillation or intraperitoneal injection of fiber suspensions. Man-made fibers have produced lung fibrosis and mesotheliomas in such tests, albeit at much lower yields than asbestos. For all durable mineral fibers, critical length limits must be exceeded to warrant concern about chronic toxicity; i.e., 2 microns for asbestosis, 5 microns for mesothelioma, and 10 microns for lung cancer. Fiber width must be less than 0.1 microns for mesothelioma, and larger than this limit for asbestosis and lung cancer. The human health risks for most fibrous glass products are either low or negligible for a variety of reasons. First, most commercial fibrous glass products have mean fiber diameters of approximately 7.5 microns, which results in mean aero-dynamic diameters approximately 22 microns. Thus, most glass fibers, even if dispersed into the air, do not penetrate into the lung to any great extent. Second, the small fraction of smaller diameter fibers that do penetrate into the lungs are not persistent within the lungs for most fibrous glass products due to mechanical breakage into shorter lengths and overall dissolution.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of Fiber Characteristics on Lung Deposition, Retention, and Disease

There is abundant epidemiologic evidence that asbestos fibers can cause lung fibrosis (asbestosis), bronchial cancer, and mesothelioma in humans, as well as limited evidence for such effects in workers exposed to slag and rockwool fibers. Epidemiological evidence for human disease from inhalation exposures to conventional fibrous glass is negative. While health concerns based on the morphological and toxicological similarities between man-made fibers and asbestos are warranted, it is important to note that most of the toxicological evidence for glass fiber toxicity in laboratory animals is based on nonphysiological exposures such as intratracheal instillation or intraperitoneal injection of fiber suspensions. Man-made fibers have produced lung fibrosis and mesotheliomas in such tests, albeit at much lower yields than asbestos. For all durable mineral fibers, critical length limits must be exceeded to warrant concern about chronic toxicity; i.e., 2 microns for asbestosis, 5 microns for mesothelioma, and 10 microns for lung cancer. Fiber width must be less than 0.1 microns for mesothelioma, and larger than this limit for asbestosis and lung cancer. The human health risks for most fibrous glass products are either low or negligible for a variety of reasons. First, most commercial fibrous glass products have mean fiber diameters of approximately 7.5 microns, which results in mean aero-dynamic diameters approximately 22 microns. Thus, most glass fibers, even if dispersed into the air, do not penetrate into the lung to any great extent. Second, the small fraction of smaller diameter fibers that do penetrate into the lungs are not persistent within the lungs for most fibrous glass products due to mechanical breakage into shorter lengths and overall dissolution.(ABSTRACT TRUNCATED AT 250 WORDS)

養液栽培用ロックウール培地の利用

This study was carried out in order to analyse the physical and chemical characteristics of rockwool mat as a carrier of nutrient solution in soilless culture. The volume of the solid phase in the mat was very small (about 3%) . The saturated water capacity was 90% or more, and most of the water in the mat was held at a high matric potential (below pF 1.5) . When the water saturation over the mat was above the range of 50%, the water saturation degree in the deep layer (below 1/2 of the 7.5 cm mat depth) was stabilized at around 70-90%, whereas in the superficial (more than 1/2 of the depth) the water saturation degree showed large variations between 30% and 80%. These variations in the shallow layer may contribute to the supply of air for the plant roots. Excessive drainage caused a decrease and considerable imbalance in the water saturation degree in the mat. And the former saturation level could not be restores by standard drip irrigation. It was seemed important during plant cultivation that a level of 50% or more of water saturation was maintained all over the mat. Since rockwool fiber did not effect significantly the content of PO43-and Ca2+ of the nutrient solution in the mat, such factors can be disregarded in the regulation of the nutrient solution for soilless culture.

最近の無機繊維質断熱材料

Recently the requirements for the performance and applicability of the thermal insulation materials have become intensified. Responding to these requirements, many kinds of insulation materials are being developed excellent in heat resistance, thermal shock resistance, insulating property, strength, applicability, etc. Synthetic inorganic fiber is one of the representative insulation materials among the porous materials excellent in insulating properties and its application becomes much wider.Here I would like to introduce the outlines and new applications of glass fibers, rockwool fibers, ceramic fibers and alumina fibers which are now widely used. Among these fibers, I can select the following three fibers which are having the novelties and newness.1. Light weight and high strength molded shapes of ceramic fibers.2. Fire resistant refractory board of alumina fibers up to 1, 800°C.3. Reusable thermal insulation tiles for the space orbitor.

Antagonistic Pythium against pathogenic Pythium on cucumber roots1

Antagonistic microorganisms introduced into the growing medium, the seed or the root, have been shown to reduce the attack of many soil‐borne plant pathogenic fungi. In 1983, three experiments with Pythium oligandrum were carried out using cucumber seedlings artificially inoculated with Pythium splendens. The seedlings cv. Ideal Nova were grown in shallow boxes containing granulated rockwool fibre (Grodania). The plants were grown at a minimum temperature of 20°C in a glasshouse. Plants were treated with the antagonist either by coating the seeds, or by applying a disc of a PDA‐culture to 9‐day old seedlings. The pathogen was introduced 9 or 5 days later, respectively, by adding PDA culture discs to the rockwool; 15 and 38 days later, the area with attacked roots was calculated as a percentage of the box‐bottom area. The experiments showed that it is possible to control P. splendens by either method of application. P. oligandrum was able to colonize the seed and rhizosphere and suppress P. splendens for at least 38 days. If future experiments are similarly positive, the methods for use in commercial horticulture should be worked out as soon as possible.

Solubility of rockwool fibres in vivo and the formation of pseudo-asbestos bodies.

Solubility of rockwool fibres in vivo and the formation of pseudo-asbestos bodies.

The limit of detection of amosite in two forms of calcium silicate matrix

Preparation procedures are examined by which the length of amosite fibres may be reduced so that preferred orientation is removed thereby providing samples suitable for quantitative X-ray diffraction analysis. Grinding in methyl alcohol produced samples from which X-ray diffraction gave major peak intensities reproducible to within ±2%. X-ray analysis has been carried out on samples of either calcium silicate powder or a lagging material which consists largely of a calcium silicate matrix reinforced with rockwool fibres which contain known additions (≤ 10 wt %) of amosite. The limits of detectability of amosite in both of these matrix materials, based on three diffraction peaks 110; 060:310; 240, have been established. It is concluded that for a mixture of amosite in calcium silicate powder, the limit of detectability is 0.4± 0.1 wt % and for amosite in lagging material, the limit of detectability is 0.2± 0.1 wt %. These are discussed in terms of differences in the physical distribution of the matrix materials.