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Failure characteristics of Gr/PEEK were studied, using an experimental investigation and a fully nonlinear ply-by-ply finite-element technique. The stacking sequence of the laminates (with centrally located holes) investigated were: 0, 90, ±45 deg, (0/45/90/−45 deg)2s and (0±45/90 deg)2s. The [0 deg] laminate failure was characterized by splitting at the extremities of the hole and along the fibers. The [90 deg] laminates failed in the transverse direction, whereas the [±45 deg] laminates exhibited considerable elongation to failure. In the case of the quasi-isotropic laminates, the failure progression appeared to be due dominantly to matrix cracking followed by fiber failure. Analytical predictions of the failure process showed reasonably good correlation with the experimentally determined data.

Inaccuracies in using the off-axis tension test are caused by the nonuniform stresses produced by the end constraints. The purpose of this study is to show that these nonuniformities can be virtually eliminated by adjusting the amount of tab clamping and selectively locating the point about which the clamp may rotate.

A comprehensive survey has been carried out on the occurrence ofAspergillus species in the respiratory tract of patients of bronchopulmonary diseases in Delhi. In all, 1238 clinical specimens, which included 1082 sputa, 143 bronchial aspirates and 13 throat swabs obtained from 812 patients, were examined. Of these 61.7 per cent patients were culturally positive yielding 29 different species ofAspergillus. The prevalence of aspergilli in sputa was significantly higher than in the bronchial aspirates.Aspergillus niger was the commonest species isolated showing a prevalence of 36.7 per cent. It was followed byA. flavus, A. nidulans, A. terreus, A. versicolor, A. sydowi, A. japonicus andA. oryzae. None of theAspergillus species showed a significant correlation with any of the diseases, or the type of treatment the patients had received. Of the 8 broad occupational groups investigated farmers and labourers showed higher prevalence ofA. niger andA. flavus. The prevalence ofAspergillus species in the throats of healthy persons was 16 per cent withA. versicolor being the commonest species followed byA. flavus, A. amstelodami, A. sydowi andA. terreus. A comparison of the prevalence ofAspergillus species in the patients, healthy individuals and atmosphere of Delhi appears to support the view that the aspergilli are transient residents in the human respiratory tract following their inhalation from the environment.

Available published reports on deep mycoses in India have been critically and exhaustively reviewed. So far there seem to be only 9 cases of actinomycosis reported, mostly of thoracic type and diagnosed on the basis of the presence of “sulphur granules” in the lesions. Nocardiosis and its chief causal agentNocardia asteroides have received particular attention in recent studies. To-date there are 18 authentic cases reported from India and significantly 12 of these have been diagnosed by applying the paraffin bait technique to the isolation ofN. asteroides from sputa and other clinical specimens. In most of these 12 cases timely diagnosis allowed for the successful treatment of the disease with heavy doses of sulphadiazine. Case reports on cryptococcosis which include 26 adequately documented cases, have been published from various parts of the country. Occurrence ofCryptococcus neoformans in soil and its association with old pigeon excreta have also been confirmed by studies done in some northern and western regions of this country. The status of histoplasmosis in India still remains a debatable subject although there is a suggestive evidence that the disease may be endemic in the northeastern parts. There are 9 case reports in which diagnosis has been supported by histopathologic findings and in 3 cultures have also been positive. However, attempts to isolateHistoplasma capsulatum from soil or any other extra-human source have remained futile and the limited surveys have revealed only low skin sensitivity to histoplasmin and none to blastomycin and coccidioidin. As yet there is no authentic case of blastomycosis, coccidioidomycosis or paracoccidioidomycosis reported from India. Two cases of invasive aspergillosis and 6 of bronchopulmonary aspergillomas have been published. In the latterAspergillus fumigatus, A. niger andA. flavus have been found to be the aetiologic agents. In addition, a recent report on a series of 8 patients recognises for the first time the occurrence of allergic aspergillosis in this country. Two cases of phycomycoses, involving the lungs in one and brain in the other case have been described. Diagnosis of bronchopulmonary candidiasis has been claimed in as many as 16 patients by several authors but in none the evidence is unequivocal. The isolation ofCandida viswanathii from the cerebrospinal fluid of two fatal cases is suggestive of the possible aetiologic role of this new yeast in human meningitis. Besides, there are 3 cases of brain mycoses described in Indian literature, two due toCladosporium trichoides while in the third caseUstilago maydis, the causal agent of maize smut, has been implicated.

The highest production of extracellular cellulases (Filter paper activity, Carboxymethyl cellulase and β-glucosidase) by Trichoderma harzianum was achieved on delignified wheat straw. Glycerol at a concentration of one per cent strongly repressed the formation of all the cellulolytic components. Addition of cyclic AMP did not relieve the repression caused by glycerol but lowered the level of existing cellulase enzymes.