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With ever increasing paper machine speed, it has become desirable to minimize the sheet moisture content at the exit of press in order to maintain higher production efficiency and higher drying efficiency.For this purpose, elastoma cover materials for press rolls are to be kept as hard as possible and also nip pressure as high as possible, which is recent fundamental designing theme of high speed paper machine press part. This, however, constitutes a very severe condition for elastoma covered rolls and cover damages have taken place on press rolls in high speed paper machines. The reasons of these damages are mechanical problems and elastoma cover internal heat generation by hysteresis, both of which are caused by the above mentioned condition (i.e, high nip pressure at high speed). The hysteresis problem cam not be neglected as the machine speeds become higher. This paper shows results of analysis of this problem and calculates how much power is absorbed for internal heat generation in relatoin to total press section power consumption. These calculations were made on the basis of actual operating conditions on two machines. The calculations of actual amount of internal heat generation was also made by knowing the measurable factors for power consumption. Another investigation was performed by using experimental apparatus and a covered roll as a model at which point the generated internal heat damages the cover. It was found that the damage occurs when heat generating amount per rubber cover unit weight reaches up to 0.0840.087 kcal/kg/sec. In case of the two machines mentioned, nip pressure were 80 kg/cm, and machine speed was 600 m/min for one and 720 for the other. The generated heat was measured to be 0.0210.024 kcal/kg/sec. So, in these two cases, thermal safety factor is 34. In a machine of this size, however, if machine speed goes up to 1, 000 m/min, heat generation radically increased to 0.044 kcal/kg/sec (safety factor : 2), which will probably causes operation and maintenance trouble for elastoma covered rolls. Temperature distribution in the elastoma cover by internal heat generation appears higher from the surface to the inside. I would like, however, to leave this problem as a theme to be investigated in the future. The cover material tested in this report was polyurethane type synthetic material (hardness P & J 5).

Pressure pulses of 8.2 × 107 dyn cm-2, each lasting for about 0.01 sec, were applied to paper, and the scattered light from it was measured simultaneously in order to study the response of pores in paper under dynamic conditions. During the compression phase the deformation in pore surface, i.e. the loss in fibre-air interface, is found to be linearly related to the square root of pressure, and the minimum pressure required to compress a paper to the non-porous state is estimated to be around 5 × 108 dyn cm-2, depending on the type of paper. The decompression curve, however, always follows a different path; thus, a cycle of compression and decompression shows large hysteresis. An approximate calculation is made of the energy loss per cycle, and this shows the associated temperature rise to be less than 1 degc. The delayed recovery from compression is large compared with the elastic recovery, but the permanent set is very small. Both the resistance of pores to compression and the energy loss per unit volume seem to be related to the paper density.

The variation of the coefficient of friction (0$\cdot $57 to 0$\cdot $88) with surface roughness is investigated experimentally in the case of emery paper sliding on various grades of emery paper. It is established that the main variable part of the friction is a function of the ratio of the radii of the emery particles in the two surfaces, and is a minimum when the radii are equal. Theoretically it is shown that the work done in the repeated up-and-down motion of the smaller particles against the elastic backing, as they slide over the larger particles in the opposing sheet, accounts well for the form and magnitude of this friction component, the fraction of the energy lost in the hysteresis being 0$\cdot $6. The remaining practically constant part of the friction is then 0$\cdot $42, which is appreciably larger than the friction of sapphire on sapphire, 0$\cdot $2, but is not far from the value 0$\cdot $36 determined experimentally for a chip of mineral emery sliding on a smoothed surface prepared on a fresh fracture of the mineral.

In the previous paper, it was reported that the fatigue being measured by the wire strain gauges of 3 mm in length on the micro stress-strain hysteresis loops was observed at three stages. In this paper, the fatigue stages of steel was observed and concluded as follows : (1) At the 1st stage, the yield point observed on hysteresis loop and the strain hardening varied. (2) At the 2nd stage, slip and recovery varied. (3) At the 1st stage, the fatigue damage was recovered at 600°C but at the 2nd stage it was not recovered. (4) The microcrack started at the beginning of the 2nd stage. (5) We proposed that the unstable state ξand the metastable state ηseemed to be produced by the distortion of crystal lattice, and micro hysteresis loops were caused by their accumulation. (6) The fatigue lives were prolonged when the variance of ξon the 1st stage and of ηon the 2nd stage was minimized.

The extremely interesting result,-namely, the continuous drift with other changes of the hysteresis loop,-accompanying successive sorptions and desorptions of water vapor on ferric oxide gel has been briefly indicated in a preliminary paper (17). A detailed account of this phenomenon,together with further evidence in favor of the view explaining this phenomenon of the drift of the hysteresis loop, is presented in this paper. There are on record few experiments on hysteresis in sorption with ferric oxide gel. By careful and extensive work, Lambert and collaborators (5, 6) have shown the existence of the hysteresis effect in ferric oxide gelethyl alcohol and ferric oxide gel-benzene systems.

It has been shown in a preceding paper that a reasonable two-phase model for the catalytic fixed-bed reactor in the region of multiple steady states should take into account heat conduction in the catalyst phase. In this paper the study of the proposed model will be continued using the example of the adiabatic fixed-bed reactor. It turns out that the behavior in the region of multiple steady states is essentially affected by the boundary conditions of the catalyst phase. If one assumes that the catalyst phase is isolated adiabatically at the front of the reactor, threefold stable states in a wide range of hysteresis can be obtained. If heat exchange by radiation takes place in the frontal surface of the catalyst phase threefold stable steady states can also occur but the range of hysteresis is much narrower. Twofold stable steady states exist only if the fixed-bed is composed of three parts; the first and third parts consist of inert material and the second contains the active catalyst. The results of the computation of this example will be compared qualitatively with the experiments of Padberg and Wicke.

The first part of the paper is concerned with stress-softening in rubber vulcanizates. Recent theories are briefly discussed and results are presented to demonstrate the authors' theory that the phenomenon of stress-softening in filled vulcanizates is due to the gum phase of the composite. A simple model demonstrating stress-softening effects is also presented. Following the authors' earlier work on the importance of hysteresis in determining the strength of rubber vulcanizates, in the second part of the paper, they apply this work to filler-loaded vulcanizates. It is found that when data are expressed independently of time and temperature, unfilled and filled results can be unified by the use of a simple hydrodynamic correction factor. On the other hand, when data are expressed in terms of time or temperature, an order of magnitude is obtained between the gum and filler-loaded vulcanizate results. The meaning of this anomaly is discussed and the authors' own conclusions on the most likely type o...

In a previous paper Miss Calderwood and the present author examined the losses in the lead sheath of a single-core cable when carrying an alternating current, and concluded that, provided the outgoing and return cables were laid within a certain limiting distance of one another, no difficulty would arise due to eddy currents in the sheaths at normal frequencies. In the present paper this work is extended to cover the case of single-core cables that are both lead-covered and armoured. A theoretical investigation of the reactances and losses is carried out and is checked against the actual test figures obtained by Harvey and Busby. It is shown :- 1. That the flux in the armour, the reactance due to that flux, and the appropriate hysteresis and eddy losses can all be approximately predetermined. 2. That for low-tension transmission, lead-covered and armoured cables are impracticable with armouring as at present constructed. 3. That the use of such cables for e.h.t. transmission is not precluded by the magnetic conditions introduced by the armour, and consequently such cables are practicable. There would, however, be some difficulties to be overcome due to large capacity currents when the transmission distance is great.

Magnetization and Hysteresis in Hematite Crystals; Experimental Procedure.---In a previous paper, the author has given the results of an investigation of the magnetic properties of crystallized hematite, the measurements being of the force exerted upon a sphere when it is placed in a non-uniform magnetic field. The present paper contains some results obtained by measuring the couple exerted when a hematite sphere is suspended in a uniform magnetic field. The couple in a uniform field measures the component of magnetization perpendicular to the field; the force measures the component parallel to the field.Experimental Data.---The paper contains (1) magnetization curves (Fig. 4) for two specimens of hematite; (2) hysteresis loops at fields from 9.5 to 1020 gausses, some obtained with a rotating field (Figs. 6, 7, 8, 9, 11), the others with an alternating field (Figs. 10, 11); (3) a graph representing components of magnetization parallel and perpendicular to the field (Fig. 12).Deduction, The normal magnetization curve of hematite consists of a sharp rise followed by a slow increase, which is proportional to the field strength. The hysteresis energy loss increases with an increase in the maximum field applied up to a certain field, and thereafter the area of the hysteresis loop remains constant. For the specimen on which most of the present measurements were made, the hysteresis loss is constant for field strengths above about 150 gausses.

A new ferromagnet has been studied in the experiments reported in this paper and the hysteresis properties explored for the first time. The magnetization may arise from electrons trapped on the numerous dislocations in pure, single crystals of alkali halides. The ferromagnetic moment could be caused by some 1014 electrons/cm3 which are trapped on dislocations and whose spins are aligned. New measurements are reported in this paper giving the torque on the magnetometer as a function of applied field strength. Both the behavior of the ferromagnetic component and the induced magnetic moment are brought out clearly in the present work.

In a previous piece of work(1) numerous data were obtained on the dependence upon magnetizing field of the Benedicks e.m.f. in nickel wire. The work was restricted to a study of the effect of the initial increase of magnetizing field, no hysteresis loops being examined. The curves were most remarkable in that the change of e.m.f. depended upon the direction of the magnetizing field with respect to the temperature asymmetry. In the paper quoted, it was suggested that the curves should be resolved into two components, symmetrical and anti-symmetrical with respect to the field. In the present paper the former component is termed the normal component, because, as is shown later, a simple explanation of it can be given at once. We call the antisymmetrical component the anomalous effect.