Interstitial, occupational causes

Pneumoconiosis is an interstitial pneunomia caused by irritation of the lungs during occupational exposure to dust particles. Silicosis is the most serious of these diseases and is contracted by inhalation of fine particles of silica over long periods of time in gold mines, tin mines, stone quarries, and during sand blasting. 

Toxicology. Cobalt causes skin irritation, allergic contact dermatitis, and occupational asthma interstitial pulmonary fibrosis is associated with exposure to hard metal dust (tungsten and cobalt). 

Hexagonal AB5 compounds form orthorhombic hydrides. Basal plane expansion, caused by hydrogen occupation of interstitial sites (4), change the compound s structure and can be ordered or disordered. For example, Kuijpers and Loopstra (4) found, by neutron diffraction, that the deuterium atoms in PrCo5D4 were ordered on certain interstitial octahedral and tetrahedral sites. The sites occupied by hydrogen in various AB5 hydrides are not fully understood because of insufficient neutron diffraction data. The available information is considered in the section on configurational entropies. 

For regulatory purposes, the Occupational Safety and Health Administration (OSHA 1992) concluded that there was insufficient evidence that nonasbestiform forms of tremolite, actinolite, and anthophyllite will produce adverse health effects of the same type and severity produced by chronic exposure to amphibole asbestos (OSHA 1992 Vu 1993). Nevertheless, the reader should be aware that repeated exposure to excessive amounts of insoluble dusts of any type can cause adverse health effects including interstitial pulmonary fibrosis (ACGIH 1996 OSHA 1992). 

Whether it is possible for a tetrahedral cluster to accommodate an H atom in its interstitial cavity without causing substantial swelling and hence destabilization of the cluster is an intriguing question. Although the occupation of tetrahedral holes is a well-docixmented phenomenon in binary metal hydrides where the metallic lattice... 

Hydrogen-absorbing materials easily lose their hydrogen-uptake capability mostly by (i) degradation of crystalline structures to amorphous states, which causes a decrease in the number of interstitial sites in the crystalline lattice available for protium occupation (ii) disproportionation of crystalline compositions, which results in a decrease in hydrogen uptake capability (iii) surface contamination, which causes the formation and growth of inactive surface layers [214]. 

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