Metallographic investigations of the failed superheater tubes used in liquid hydrogen plant

2.25Cr–1Mo low alloy steel tubes of diameter 42.5 mm ID and 46.5 mm OD were used in superheater of liquid hydrogen plant. This superheater had 10 rows of tubes for carrying naphtha and steam and is heated by flue gas. The flue gas directly impinges on the first three tubes of the tube bank. A failure occurred in the first tube leading to the removal of a portion of the material causing to shut down of the plant.Detailed metallurgical investigations were carried out to understand the cause of failure. This paper brings out the metallographic investigations on the failed tubes and the necessary remedial actions thereon.     

Stereotaxic surgery of temporal lobe epilepsy

Forty patients with temporal epilepsy were operated on with a stereotaxic technique. Eleven patients had a unilateral localization of the epileptic focus, and in 29 bitemporal foci were diagnosed. In evaluating the results of the treatment the dynamics of the epileptic fits, the peculiarities of changes in the mental status, and the degree of social adaptation were taken into consideration. A postoperative improvement was achieved in 73% of the patients with monotemporal lesions, while in those with bitemporal epilepsy and distinct persistent mental disorders the state was improved in 44% of the cases. Indications for the choice of the zone of destruction depending on the clinical peculiarities of the lesion are presented.     

Changes in nitrogen metabolism in young cattle following ultraviolet irradiation and feeding on urea

Some indexes of nitrogen metabolism in blood, rumen content and urine of bull-calves fed on urea were studied as affected by UV-radiation. The content of protein, nonprotein, amine nitrogen, urea and ammonia in the rumen content and blood as well as as intensity of urea nitrogen and ammonia excretion with urine were determined. It is established that when 25% of protein necessary for the organism was replaced in the ration by urea, UV-radiation with a dose of 120 merg/h-m2 lowers already at the beginning of irradiation the amount of amine nitrogen and further the protein one in the young cattle rumen content. In blood of the irradiated bull-calves at the beginning of irradiation the level of amine nitrogen decreases, the level of nonprotein nitrogen lowers with a longer irradiation. The content of protein nitrogen in blood at that time increases. It was found that the content of ammonia in the bull-calves rumen during the first twenty-hours lowers, the amount of urea in blood does not change essentially. Simultaneously the ammonia excretion with urine intensifies, at the same time the excretion of urea nitrogen with urine does not differ essentially from that in the control bull-calves. In the bull-calves under study the nitrogen balance and average daily gains increase that may testify to the fact that UV-radiation in the applied dose stimulates a more complete utilization of urea nitrogen for the synthesis processes in the organism.     

Photooxidation of P-960 and photoreduction of P-800 (bacteriopheophytin b-800) in reaction centers from Rhodopseudomonas viridis

CT scans of 9 patients with orbital pseudotumor (bilateral in 6 and unilateral in 3) showed findings distinct from those observed in Graves' ophthalmopathy. In bilateral involvement, they ranged from localized mass lesions to complete obiliteration of normal orbital CT anatomical landmarks; diffuse or multifocal lesions involving the posterior globe and muscle insertions were most typical of the diagnosis. However, findings in unilateral psedotumor may be indistinguishable from orbital mass lesions other than Graves' ophthalmopathy. Serial CT scans were used to show progression of disease and response to treatment.     

Influence of the dentate fascia on the sensory responses of neurons in hippocampal field CA3

In experiments with unanaesthetized rabbits the influences of electric stimulation of the dentate fascia (DF) on the extracellularly recorded spontaneous and evoked activity of the CA3 neurones were investigated. Stimulation of a fixed locus in the DF during recording in the CA3 by a microelectrode, shifted along the longitudinal axis of the hippocampus, supported the notion of the topical, "segmental" organization of connections between the DF and CA3. A relatively narrow "active zone" (approximately 700 nm) appeared in the CA3 during the threshold DF stimulation: it was bordered by zones with predominantly inhibitory responses to stimulation. The CA3 neurones in the "active zone" rapidly lost their reactivity to sensory stimuli. In the "inhibitory" and "zero" zones the normal level of reactivity to sensory stimuli was preserved.     

Morphological effects in rats following a 22-day space flight

A morphological examination of 27 rats flown onboard the biosatellite and sacrificed on the 1st-2nd and 26-27th postflight days demonstrated no significant changes in the structural organization of the vital organs and systems of the animal body. It was, however, found that the space exposure induced morphologically detectable changes in the musculo-skeletal system, hemo- and lymphopoiesis, hypothalamic-pituitary-adrenal system and the juxtaglomerular apparatus of the kidneys. The changes were reversible and nonspecific, and could be seen in animals exposed to ground-based hypokinetic and other stress experiments. Postflight the animals developed some reactions that were similar to those in humans. This helps to identify the morphological substrate of certain changes in the human body and to investigate their pathogenesis.     

Biogenesis of cellulolytic enzymes by Trichoderma ligorum on media with "inductor"

Identical distribution of C2- and Cx-cellulase activities of enzyme complexes produced by Trichoderma lignorum on a medium with lactose, a soluble "inductor", and on a medium with cellulose was found by means of disc elestrophoresis in polyacrylamide gel. The maximum rate of synthesis of cellulases on the medium with lactose was registered during the highest deceleration, and even complete cessation, of the fungal growth. During this phase, only one electrophoretically homogeneous cellulase component with Rf of 0.44 possessing all types of the cellulase activity is present in the cultural broth. In the course of growth of the fungus on cellulose after 48 hours, also only one electrophoretically homogeneous component with Rf of 0.44 was found in the cultural broth when the rate of the substrate degradation was highest. The appearance of minor protein components with the activity of cellulase at later stages of cultivation after cessation of the fungal growth is supposed to be caused by modification of the main cellulase component with Rf of 0.44 by the growth medium.     

Effect of penetrating radiation on skeletal muscles of rats in weightlessness

The isoenzyme composition of lactate dehydrogenase of soleus and plantaris muscles of rats flown for 20.5 d aboard the biosatellite Cosmos-690 and irradiated with a dose of 800 rad was investigated. The muscles exposed to weightlessness per se and weightlessness combined with radiation showed similar changes in their carbohydrate metabolism. On return to 1 G, readaptation of irradiated rats developed less rapidly than of animals exposed to weightlessness alone.