Stationary Manner Research Articles

Environmental and genetic control of the larval diapause of the Southwestern corn borer, Diatraea grandiosella

ABSTRACT. The interaction of photoperiod and temperature in the regulation of the induction and termination of the larval diapause of the Southwestern corn borer, Diatraea grandiosella Dyar (Lepidoptera), was examined. A population originating from south‐eastern Missouri had critical daylengths for diapause induction of about 15h 5min (ecological threshold) and llh (physiological threshold). The ecological threshold was more stable than was the physiological threshold at temperatures lower than 25°C. Above 25°C the diapause response was suppressed. The insect appears to measure photoperiods in a stationary manner since a stepwise increase or decrease in photoperiod did not affect the incidence of diapause. In the critical region of the photoperiodic response curve, a higher incidence of diapause was found among females than among males. Females entered diapause later than did males, but resumed active development earlier than males. The rate of diapause development was more temperature dependent than was the rate of diapause induction, yet it was also clearly under photoperiodic control. The temperature coefficient (Q10) for this process was about 4. Several other factors including sex‐linkage, age, and geographic adaptations are involved in controlling the rate of diapause development, even more so than they are in controlling diapause induction. In the laboratory, the intensity of diapause declined gradually without larvae being exposed to non‐diapause inducing conditions. Incubation of field‐collected larvae revealed that their sensitivity to diapause maintaining photoperiods had ended by January. Three generations of selection of a Mississippi population of D. grandiosella at 30°C and LD 12:12 led to the production of an essentially diapause‐free strain and a diapause strain.

The effects of random longitudinal vibration on pipe flow of a non-Newtonian fluid

A perturbation solution to a pulsating pipe flow of a non-Newtonian fluid is developed. The pipe is vibrated longitudinally in a random stationary manner and the fluid is driven by a constant pressure drop. Three explicit constitutive equations are studied: the generalized Newtonian, the strain-rate and the strain-dependent constitutive equations. It is found that all three of them are capable of describing the flow enhancement phenomenon observed byMena et al. and that this effect is entirely an inertia effect which is exhibited only by shear-thinning fluids.

LONG PERIOD SEA‐FLOOR MULTIPLES AND THEIR SUPPRESSION*

AbstractMultiple sea‐floor reflections in deep water often are not effectively suppressed by either CDP stacking nor standard predictive deconvolution methods. These methods fail because the reflection coefficient varies markedly with angle of incidence and also because of the variation of arrival time with offset and because of dip. For a reasonablly flat sea‐floor, multiples of various orders and the primary sea‐floor reflection which have all been reflected at nearly the same angle lie along a straight line through the origin in time‐offset space. This line is called the “radial direction.” The multiples which lie along this line show a systematic relationship because they all experience the same water‐bottom reflection effect. In other words, multiples behave in a stationary manner along the radial directions on multi‐trace seismic records. A technique of multi‐channel predictive deconvolution, called “Radial Multiple Suppression,” utilizes this aspect to design Wiener operators for the prediciton and suppression of water bottom multiples.The effectiveness of the technique is demonstrated by the study of field records, autocorrelations, velocity analyses, and stacked sections before and after Radial Multiple Suppression processing.

Removal of Colour from Effluents of Anodizing Plants

SummaryWater-soluble organic dyestuffs used for dyeing the anodic coatings on aluminium cause hardly any damage to the biocenosis of the water into which the effluents of anodizing plants are released, as ecological laboratory investigations and years of practical experience have shown. However, the extremely high tinctorial strength of such dyes, even after being heavily diluted (less than 0·1 ppm) cause conspicuous and unsightly discolouration of the water into which the effluent is released. Since in mechanical-biological water purification systems these dyestuffs can only be eliminated in insignificant amounts, concentrated dye solutions must be decolourized before being drained. Coloured running rinse water, however, due to its slight discolouration, normally requires no special treatment.A number of different processes are available for eliminating dyestuffs by chemical decomposition or by physical separation, such as adsorption by activated carbon, precipitation, reverse osmosis, evaporation and incineration, catalyzed, radioactivated or electrochemical wet oxidation under aeration, chemical oxidation (e g with ozone), or chemical reduction (e g with hydrosulphite).Adsorption with activated carbon represents an especially economical and flexible solution to the problem of decolonization. This process can be carried out both in a stationary manner by the suspension principle as well as by the percolation principle. Moreover, there are no problems relating to secondary pollution of the effluent or with disposing of the solid waste.

The vibrations of a random elastic string: the method of integral equations

The theory of Fredholm integral equations is applied to the problem of determining the natural frequencies of transverse vibrations of a tightly stretched elastic string whose mass per unit length varies with position in a stationary random manner. Upper and lower bounds for the statistical moments of the frequencies are given in terms of corresponding moments and appropriate correlation functions for the random linear density. The adequacy of the bounds decreases for the higher frequencies. Extensions to more general random boundary value problems are also indicated.

Verbrennung eines flüssigen brennstofftröpfchens

Critical ignition and extinction processes in the burning of a liquid droplet floating in a turbulent atmosphere are mathematically discussed. The analytical-numerical investigation was carried out with the aid of the program-controlled computer IBM 650. In the case of the model employed it is assumed that the homogeneous reaction takes place in a narrow zone at rest in relation to the droplet and that the reactants are highly diluted with inert gas, so that the convective exchange (Stefan flow) can be neglected. The course of reaction is treated in a quasi stationary manner. The critical ignition and extinction processes are stability problems. The influence of the ten basic constants on the course of reaction, especially during the induction period, and on the ignition process, is discussed. For taking the convective exchange into account an iteration process is briefly described.

Effect of Molecular Nitrogen on Molybdenum at High Temperatures

TREATING molybdenum wires of 0·2 mm. in a stationary manner by passing electric current through them and testing the behaviour of the wires under tensile stress, we have found that specimens heated in nitrogen are of quite a different character from those treated in hydrogen, argon or in vacuo. The yield point (in general, at the yield point of the wire plastic deformation of the metal commences) and the elongation of the wire in particular are very markedly influenced by nitrogen. Fig. 1 shows the load-extension curves of wires treated in nitrogen, the arrows indicating the yield point of the wire.