Calorific Energy Research Articles

Nucléation par le borax du sulfate de sodium dispersé. application possible au stockage thermique

On a etudie par analyse enthalpique differentielle la cristallisation de gouttes de solutions aqueuses de Na2SO4 (0,9 mole Na 2SO4 ; 10 moles H2O) contenant un exces de Na 2B4O7, 10 H2O solide et dispersees dans un support emulsionnant. On observe deux maxima de cristallisations a + 7 °C et - 2,5 °C au lieu de - 41 °C en l'absence de borax. Entre le premier et trentieme cycle de refroidissement-rechauffement on observe une augmentation de 15 % de l'energie liberee lors de la cristallisation. Ce type de nucleation pourrait presenter un interet pour la realisation de stockage thermique.

Gravity waves generated during magnetic substorms

During magnetically disturbed days, wind and temperature data obtained in the F-region from incoherent scatter, show strong oscillations of the ion temperature and velocity with period of some 2 hr. These oscillations can be interpreted as due to atmospheric gravity waves travelling Southwards. In this paper, the data are compared to auroral magnetograms. Temperature and velocity oscillations appear to follow magnetic events such as substorms, with a time delay of about one hour. Theoretical computations show that the intense heat deposited in the auroral E-region during a magnetic substorm, can generate atmospheric waves which propagate towards midlatitudes. The characteristics of the computed waves are in close agreement with the observed ones. Finally, the calorific energy deposited at midlatitude by dissipation of such waves is evaluated. The resulting thermospheric temperature increase is comparable to that predicted by Jacchia's model.

A Theory of Muscle Mechanism

IN an article in the magazine Cheap Steam, which has been reprinted in pamphlet form, Walter Gold-stern has put forward a theory as to the methods by which muscles operate. The muscle is described as an engine transforming the calorific energy of food into power and heat. Structurally, the muscle is formed of a large number of fibres about 2 in. long and 1/500 in. in diameter, each consisting of many fibrils bound together by an elastic covering, the sarcolemma. By the operation of a nerve, one or more bundles of fibrils, according to the power required, are caused to contract. The author sets himself to supply an answer to the question as to the mechanism by which the muscle fibre is caused to contract. This, he says, is effected by a small internal pressure. He compares the sarcolemma to a long, narrow tube closed at both ends into which liquid under pressure is pumped. As the pressure increases, the tube becomes enlarged centrally and adopts a barrel shape, and would tend ultimately to become spherical. It is suggested that this central distension is accompanied by diminution in length ; but this rather doubtful point is not cleared up, and if it were admitted it would still require to be shown that it would occur against the pull which the muscle is understood to be exerting ; and also the method by which the pressure is produced and where the added liquid necessary to produce it can come from. A more acceptable explanation is conveyed in the suggestion that this central expansion of the sarcolemma is made to aid the lengthwise contraction by what is called lever action, but which might more suitably be described as the bowstring effect. of the muscle fibres being pulled apart at the centre and producing a considerably magnified endwise pull.