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Eine neue Technik, die einen einzelnen Natrium-Jodid-(Tl)-Detektor (9 cm x 6,3 cm) in zwei Positionen verwendet und auf der Ansprechkurve des Detektors beruht wird beschrieben. Ebenso wird ein anderes Verfahren zur Energiewahl angewendet, das sich als zweckmäßig erwiesen hat, um die Zählratenabhängigkeit von der Quellentiefe zu reduzieren. Verschiedene Teile des Compton-Continuums wurden als Grundlage der Messung verwendet anstelle von Tal und Photo-Peak. Für transversale Uniformität wurde gefunden, daß das Energieband, das einer 50% normalisierten Zählrate der Halbtiefe entspricht zu einer flachen Ansprechkurve mit minimalen Variationen führt. Für die longitudinale Uniformität muß die Lagedifferenz der beiden Positionen des Detektors ungefähr gleich der vollen Weite beim Halbmaximum der Ansprechkurve sein. Die Technik des Bezugs zur Ansprechkurve, die beschrieben wird, ist verschieden von der üblicherweise verwendeten Technik der Iso-Ansprechkurven.

In a previous paper [1], the concept of the dynamic sensitivity of a system state and its performance was introduced for a continuous linear system with small arbitrary perturbations in the system parameters. In this paper this concept is extended to a class of nonlinear and linear systems. It is shown that plant and controller parameters uncertainties (internal disturbances) may be regarded as a state-dependent noise at the input of the plant. The analysis is then applied to a continuous linear situation. As an example, a satellite attitude control with randomly varying tracking signals is considered; and the dynamic sensitivity behavior of the parameter-uncertainty-transmission path, from the controller parameters to the process performance index, is studied.

Trigatron breakdown characteristics were studied in atmospheric air for gaps up to 15 cm in length. Under negative impulse voltages with a positive trigger pulse applied in the grounded electrode, the minimum breakdown values corresponded closely to the negative sphere-rod gap breakdown values. While under positive impulses the trigatron broke down at approximately the same voltages as the positive sphere-rod gaps. The low breakdown in trigatrons under negative impulse voltages was preceded by a positive leader identical to that observed in positive sphere-rod gaps. The higher breakdowns under the positive voltages resulted from a negative leader. The results suggest that the space charge from the auxiliary spark distorts the initially uniform field in the gap and the breakdown follows the nonuniform field breakdown mechanism.

1. Four trematodes,Gastrothylax crumenifer, Cotylophoron cotylophorum, Paramphistomum explanatumandFasciola giganticahave been used for quantitative analysis of their inorganic constituents.2. Calcium, magnesium and phosphorus content have been determined.3. All the four trematodes contain large amounts of phosphorus (0·61–1·05%); but the amounts of calcium (0·025–0·045%) and magnesium (0·029–0·065 %) are small.

A method is proposed in this paper for the synthesis of an adaptive controller for a class of model reference systems in which the plant is not known exactly, but which is of the following type: single variable, time varying, either linear or nonlinear, of n th order, and capable of m th order input differentiation. The model is linear, stable, and of n 'th order, where (n - m) \leq n' \leq n . The only knowledge of the plant that is required in this synthesis procedure is the form of the plant equation and the bounds of b_{m}(t) , the coefficient of the m th order plant input derivative. The synthesis procedure makes use of an unique function, called the characteristic variable, and Lyapunov type synthesis. The introduction of the characteristic variable reduces the synthesis problem to one that involves a known, linear time-invariant lower order plant. The control signal is generated by measuring the plant and model outputs, and their first (n - m) derivative signals. This ensures that the norm of the (n - m)- dimensional error vector is ultimately bounded by e, an arbitrarily small positive number provided \xi(t) , the characteristic variable, is bounded. Two nontrivial simulation examples are included.

In this paper three related methods are proposed for eliminating the effect of low frequency polynomial type drift in the crosscorrelation identification of linear time-invariant discrete systems using pseudorandom sequences. The methods are similar to the one suggested by Macleod [8] in that a convolution summation using alternating sign binomial coefficients is performed on the measured system output. However, the proposed methods are computationally simpler than Macleod's method since no deconvolution process is required. Digital computer simulation results are presented to show the effectiveness of these methods in the presence of both low and high frequency disturbances.

GRATIFYING developments in the therapy of gout have occurred during the past five years. Until 1950, it was not possible to maintain the serum uric acid at normal levels, prevent urate deposition (...

Amperometric titration of mercury (in the range of 0–4 to 3.5 mg) has been carried out with 2-mercaptobenzoxazole with a stationary electrode in stirred solution in a sodium acetate-acetic acid medium.

1.1. The subject of temporal lobe epilepsy is reviewed briefly. 2.2. Clinical data have been presented in six epileptic patients in whom behavior difficulties were a major problem in management. A diagnosis of temporal lobe epilepsy was made on the basis of the clinical features and the preoperative electroencephalographic tracings in all these patients. 3.3. Spiking was recorded from the depth electrodes implanted in the amygdaloid region in all six patients. 4.4. In all except one patient, electrical stimulation of the amygdala brought out many of the features of temporal lobe epilepsy. Included in the responses to electrical stimulation were elevation of heart rate and blood pressure, pupillary dilatation and changes in respiration. 5.5. While our current data do not permit us to ascertain the exact role of the amygdaloid region in the genesis of temporal lobe epilepsy, they do suggest that this region is part of the neurophysiologic unit involving temporal lobe epilepsy and behavior.

1. The Q O 2 of adult F. gigantica has been compared with F. hepatica. 2. The oxygen consumption of the experimental parasite has been found to be very low. 3. There is a marked difference in Q O 2 values of the whole and minced parasite.

Abstract This paper reports on the results of a fundamental investigation of the behavior of rock under impact of a chisel-shaped bit. Drop-tester studies were conducted with strain gauges attached to the rock and striking bit-edge. It was established that rock be haves viscoelastically. Little correlation was found to exist between the strain wave forms detected on the rock surface and in the bit; thus, strain-time curves obtained with transducers mounted on the bit cannot be used to explain the sequence of events in rock breakage. It is estimated that nearly 1 per cent of the total energy of the blow is expended in permanent de formation of the rock. The strain-energy distribution on a rock surface as a result of chisel impact, which follows a simple law, is presented graphically. Experiments also were conducted with gauges embedded in the rock vertically below the line of impact and at an angle of approximately 43 degrees to the vertical. No essential difference was observed in the type of wave obtained with embedded gauges and with gauges on the surface, as may have been anticipated from theory. Introduction Through the ages great strides have been taken towards improvement of the various techniques applied in the breakage of rock. Indeed, numerous applications of the rock-failure process are an integral part of present-day industry, including oil well drilling. Yet, astonishingly, little is known regarding the behavior of rock under dynamic loading or the mechanism of rock failure. The value of impact loading studies from the point of view of drilling is evident, however, and requires little elaboration because impact of a chisel edge on rock forms the basic action constituting most common methods of drilling. RELATED STUDIES Impact studies of communition and fragmentation conducted by Fahrenwald, et al, Poncelet, Axelson, et al, Piret, Hartman and Pfleider, Charles and deBruyn, and others have been of considerable help in understanding rock-breakage phenomena. Further insight into the basic action of drilling and penetration has been obtained by the work of Irving, Cherkasov and Shlyapin, Borcherdt, Shepherd, Shreiner and Pavlova, Drilling Research Inc., Hartman, Appl and Gatley and several other investigators. However, knowledge concerning the stresses and strains induced in the rock and bit during impact remains scant. Recent photoelastic studies by Tandanand and Hartman (1961, 1962) have shed light on stress distributions and fracturing produced in plastics by chisel-shaped bits. In the field of transient strain pulses and their role in rock drilling, the only extensive work has been performed by Drilling Research Inc. (DRI). They attached strain gauges to the shank of a bit and conducted drop-tester studies, using a die-shaped bit to obtain force-time diagrams. Their work led to the conclusion that, for a given rock type, the first peak of force occurs at a fixed level regardless of the total energy in the system, provided it exceeds a certain minimum threshold level. Further, on this basis an explanation was offered for the sequence of events in crater formation as the result of a single blow on rock. PURPOSE OF PRESENT STUDY The investigations reported in this paper were conducted in a manner similar to the DRI approach, but with the objective of determining the strain distribution in the rock around the area of bit impact and, to a limited extent, the strain in the chisel-shaped bit itself. SPEJ P. 283^

1. The different lipid fractions inGastrothylax crumeniferafter starvation for 8–10 hr. have been estimated.2. The percentages of different fractions in the total ether extract were found to be: acetone-insoluble material 16, unsaponifiable matter 25, saturated fatty acids 5, unsaturated fatty acids 20, glycerol 2 and unidentified lipids 32.3. The above percentages of lipid fractions have been compared with the corresponding data for different parasites obtained by other workers.

An experimental investigation of the characteristics of surface waves generated by the time dependent horizontal motion of a vertical wall in water has been made, and the results compared with the numerical solutions obtained by Noda (1969) using linear theory. The experiments were made in two test flumes using various water depths, wall displacements and velocities of wall motion to determine the range of validity of the linearizaed solutions. The comparison of linear theory with the experimental data show the theory can be useful to the design engineer even for nonlinear waves at small distances from the wall.

The percentage change in weight, at 38·2 °C, in different concentrations of sodium chloride at different intervals, of a trematode,Gastrothylax crumenifer, from the reticulum of buffaloes has been recorded.A state of approximate isotonicity is reached between 0·4 and 0·5% sodium chloride.The osmotic pressure has also been expressed in terms of freezing-point depression.

A deterministic design approach is presented for controlling a class of unknown nonlinear multivariable plants operating in an uncertain environment. The approach uses a “Two-level” controller, with a feedforward controller on its first-level and, a conditional feedback controller on its second-level. In the design of the conditional feedback controller a deterministic type synthesis procedure using the Liapunov signal synthesis method is employed. It is shown that this procedure bypasses some of the rigid requirements that are imposed by the conventional type controller synthesis techniques. The applicability of this approach is demonstrated by means of a number of hybrid computer simulation studies.

This paper investigates the characteristics of the dynamics of a parameter-perturbation process in a continuous linear system. These characteristics are studied in the performance index-parameter space for a positive definite performance index function. In particular, the relationship between the static sensitivity function and the process quasilinear dynamics is established, and the minimum and nonminimum phase phenomena of the dynamics are examined. It is shown that the process quasilinear dynamics, from parameter variations to the dynamic response in the error-criterion function, are the nonminimum phase type if the quiescent value of the parameter lies on the negative slope side of the static error-transfer characteristics and derivative type at the optimum value of the parameter. Theoretical and analog simulation results are presented for a particular system.

This patient is of interest for three reasons: (1) acute rheumatic myocarditis occurred at the age of 84 years—the oldest age in which such an event has been recorded, (2) the interval between the final and the previous acute rheumatic episode was 70 years—the longest such interval reported, and (3) Aschoff nodules were present in skeletal muscles also, a finding not adequately documented and studied so far.

A design for an extensometer for measuring lateral deformations in brittle materials using LVDT's is presented. The system is sensitive enough to measure the small changes in diameter that occur in such situations, but is simple and inexpensive. The instrumentation technique also allows a choice of electronic equipment, thus making it more versatile. The extensometer may be used for lateral deformation measurements in both compression and tension experiments.