Repetitive Basis Research Articles

Синхронизация культурScenedesmus quadricauda через оптимализацию длины периода освещения

Experiments revealed that the synchronized cultures ofScenedesmus quadricauda, strainGreifswald/15, must be kept under continuous illumination throughout the whole growth phase (from the release of daughter coenobia up to the moment when all cells are capable of further reproduction). The length of the light period is among others the function of the suspension density. With regard to these facts a method of synchronization was worked out on the basis of a rhythmical repetition of the calculated light regime, corresponding to the physiological parameters of the synchronized strain under given cultivation conditions. This method enables to maintain synchronized cultures in adequate cycles for any required period, even in sufficiently dense, linearly growing suspensions. It may be applied to any chlorococcal algae; however, if coenobial types are studied, it is necessary to consider special peculiarities, which result from the regular arrangement of the cells in the coenobium.

A Multikilowatt X-Band Nanosecond Source

A new technique is presented which furnishes an exceptionally narrow pulse of 6 to 12 ns duration with steep skirts of 1 to 3 ns at peak power levels of tens of kilowatts. The pulse is derived by means of two sequential discharges in a nonresonant waveguide section. An analysis of the low-pressure breakdown of a gas under the action of intense microwave fields considerably higher than the threshold of breakdown field shows that under certain optimum combinations of gas parameters the aforementioned pulse is obtained. Experimental results show that a 70 kW rectangular pulse of 12 ns width with 2 ns skirts can be reliably generated on a repetitive basis with negligible jitter.

A Dynamic Programming Approach to a Lot Size Scheduling Problem

The problem considered is that of scheduling the production of several different items over the same facility on a repetitive basis. The facility is such that only one item can be produced at a time; there is a setup cost and a setup time associated with producing each item; the demand rate for each item is known and constant over an infinite planning horizon, and all demand must be met. A dynamic programming solution is developed. This solution is applied to a sample problem, and the results are compared with pertinent bounds.

KEWB¿Radiation Burst Test Facility

It is a well-established fact that brief pulses of intense radiation, such as those produced during a nuclear detonation, can disable, or cause serious malfunction of, most electronic systems even though they are located outside the thermal and shock destruction zones. This fact has given rise to the need for a device which can simulate the radiation environment accompanying a nuclear detonation. Coincidental with the evolution of this need, a family of nuclear reactors has been demonstrated as being capable of producing radiation bursts which, in all important respects, adequately simulate a nuclear weapon. These devices offer additional advantages over field tests involving actual detonation in that they may be operated on a routine repetitive basis at a much reduced cost and under carefully controlled laboratory conditions. The Kinetic Experiments on Water Boiler (KEWB) reactor has a demonstrated ability to perform in the capacity of a weapon simulator. This reactor is located in the Los Angeles area and is operated by Atomics International for the Atomic Energy Commission. Organizations executing Government contracts can take advantage of its availability if transient radiation resistance requirements are encountered during execution of their contract. The reactor is of the aqueous homogeneous type and produces the shortest duration pulse of any of the thermal neutron reactors operating today. Radiation pulses of varying widths down to 3.0 msec can be obtained with the assembly together with peak neutron and gamma intensities of 3 x 1016 neutrons/cm2-sec and operating today.