The essential work of plane stress ductile fracture of a strain-aged steel

The paper reports the results of an experimental investigation on the essential work of fracture of a strain-aged low carbon (0.1% C) temper-rolled 16-gauge sheet steel which has been subjected to pre-strain levels of 2 to 12% and ageing temperatures of 80 and 100C. Deep edge-notched tension specimens were used to determine the specific essential work by extrapolating the straight-line relationship between the specific work of fracture (W _f) and ligament length (I) to zero ligament length. The strain-aged steels at 80 and 100 give approximately the same specific essential fracture work of 0.18 to 0.20 J mm^–2 which is independent of the amount of prestrain. Advancing crack opening displacements (C.O.D.) have also been analysed, which give 0.60 to 0.63 mm for the strain-aged steels. For comparison, the prestrained but unaged steels have a higher essential work of fracture of 0.275 J mm^–2 and a larger C.O.D. of 0.73 mm. It is concluded, therefore, that the causes of strain-ageing embrittlement are primarily due to the reduction of both the essential work of fracture and the advancing C.O.D. at the crack tip end region.     

Transmission microscopy of the corrosion scale formed on a stainless steel exposed to liquid sodium

The scale, formed on 304 stainless steel during exposure to sodium for 85 days, was removed electrolytically, examined in transmission in the Hitachi high voltage microscope and found to consist of hexagonal close packed crystallites, typically 0.3 to 1 m in diameter. Approximately 90% of the crystallites were of basal (0001) orientation and the others either of {4, ¯1, ¯3, 15} or {¯2110} orientations. Lattice parametersa=2.96 Å andc=13.89 Å were determined by analysing electron diffraction patterns derived from the scale. Confirmatory evidence was obtained by examining the scale formed after a shorter exposure of 29 days, in the Philips EM 200 microscope. Previous studies [1, 2] have indicated that the scale may be sodium chromite (with lattice parametersa=2.96 Å andc=15.95 Å). The results of the present study are in apparent conflict with this suggestion unless a contraction parallel to thec-axis 13% is assumed.     

The kinetics of molybdenum dioxide oxidation

Powdered molybdenum dioxide was oxidized to MoO₃ in the temperature range 390 to 465°C under oxygen partial pressures of 0.016 and 0.18 atmospheres^* and under 0.009 atmospheres in the temperature interval 465 to 529°C. The course of the reaction was followed by observing weight change with time. Parabolic kinetics were evident for oxidation below 460°C. Above 460°C linear kinetics were observed. The partial pressure dependence at 407°C and 455°C was found to be approximately \(P_{O_2 }^{1/5} \) . Oxidation tests were restricted to an oxygen partial pressure of 0.009 atmosphere in the temperature range between 460°C and 530°C since above this partial pressure excessive heating occurred. For the low temperature range the oxidation was explained in terms of the diffusion of mono-and divalent oxygen interstitials. Activation enthalpies of 159±8 and 105±8 kJ/mole were obtained respectively for parabolic and linear rate processes.     

A case of reversible deafness in cystic arachnoiditis (author's transl)

A patient studied preoperatively by a neuro-otological test battery showed signs of an extensive cerebellopontine angle tumour. During the operation dense fibrotic tissue was found extending from the choroid plexus to the right acoustic nerve, which was freed and thus decompressed. Postoperatively, low frequency hearing improved markedly in the right ear. In contrast to the well-known documented cases of successful decompression of the optic nerve it has not been possible up to now to achieve a successful outcome in similar procedures on the acoustic nerve. In the described case the fibrotic lesion had obviously just caused reversible damage to the myelin sheaths of the eighth nerve, which can be interpreted as "neurapraxia" (Seddon, 1943). Further investigations in regard to the systematic elucidation of possibly reversible damage to the acoustic nerve are currently being performed at the IInd ENT department of Vienna University.     

Endocrine ophthalmopathy. Clinical symptoms, classification, diagnostic classification, indications for treatment (author's transl)

The clinical aspects and classification of "endocrine ophthalmopathy" were described. The clinical picture is of importance for the physician in nuclear medicine who is involved with the diagnosis and therapy of hyperthyroidism. In vivo and in vitro investigations in nuclear medicine regarding the classification of ophthalmic findings are derived from disturbances in control of the regulatory systems of the hypothalmas-pituitary-thyroid which are parallel to the ophthalmic processes. The clinical forms of endocrine ophthalmopathy and the thyroid findings which accompany it were systematized and an appropriate therapeutic procedure for the respective anomaly was described.     

The psychological development of orphanage-reared infants: interventions with outcomes (Tehran)

This paper describes five successive interventions in the rearing of infants at an orphanage in Tehran, with their outcomes. The outcomes were assessed longitudinally. The first of the successive groups, here called "waves", numbered 15. These Ss constitute the controls. The only intervention consisted of examining the infants every other week during the first year and every fourth week thereafter with the ordinal, sensorimotor scales of Uzgiris and Hunt. The audio-visual intervention intended for the second wave of 10 infants was tape-recorded mother talk and music under the control of the infants and mobiles that the infants could activate. This plan was never adequately implemented because of inadequate supervision. The third wave of 10 infants got extra untutored human care. The fourth wave of 20 infants got the kind of audio-visual intervention originally intended for the second wave plus access to responsive inanimate materials. For the fifth wave, numbering 11, the infant-caretaker ratio was reduced to two or three to one and the caretakers were taught the Badger program supplemented with procedures to foster vocal imitation and semantic mastery of body parts, clothing, toys, and other objects and events regularly encountered. The results show that each successive wave, excepting the second, achieved the top steps of nearly all seven of the ordinal scales at mean ages younger than the preceding wave, and the fifth wave surpassed even home-reared American children from predominantly professional families in achieving the top steps on five of the seven scales. The findings show that infants need not advance along all branches simultaneously and that the kinds of experience encountered determine the branch along which advancement occurs. A number of theoretical implications are examined. Especially important is the idea that a dependable educational psychology for infancy and early childhood calls for much more knowledge than we now have of the kinds of experience that advance development along each of the various branches.     

Mucous blanket of rat bronchus: an ultrastructural study

The tracheobronchial tree of rats was fixed by fixative vapor "from the front", thus preserving the mucous blanket for morphologic study. Electron microscopic examination of bronchi revealed the existence of osmiophilic myelin-figured lamellae in the lower zone of the mucous blanket. The meaning of this finding is discussed in terms of a 2-layer model of the mucous blanket.     

The success prognosis of plastic diaphragma operation on women with stress incontinence (author's transl)A1]

The paper refers to 126 patients on whom a plastic diaphragma operation was performed at the 1st Department of Obstet. and Gynec. of the University of Vienna. Based on the results one year after the operation, the success chances are shown and set into relation to several preexistent factors, such as severity of the incontinence, weight, parity, age and conduct of life. An increasing of the two first mentioned factors led to a significant deterioration of results. The influence of an incontinence remains incontested, yet a higher parity does not lead to significantly poorer operation results. As to the factor "age", there were no significant differences in our material. Conduct of life and additional stress in women employed in an occupation are being discussed. Furthermore it was possible to confirm the postoperative space of time needed until restoration of an undisturbed bladder function as a relatively reliable prognostic hint to the expected success of the operation. For this confirmation an objective examination method (sphincterotonometry) was used.