The isotope Re/sup 189/ was produced by fsst neutron irradiation of osmium and by the ( alpha ,p) reaction on tungsten. The rhenium was separated chemically from the target material, and beta, gamma, and internal conversion spectra were measured. The mass assignment is confirmed by the observation of eleven electromagnetic transitions in the Os/sup 189/ daughter, including the 30.8-kev isomeric transition (8 hr), all of which were known from the decay of Ir/ sup 189/. Re/sup 189/ has a half-life of 23.4 plus or minus 1.0 hr and emits betaray groups with end-point energies 1000, 780, and 725 kev, and probably others. Results of coincidence measurements lead to some new information about the level scheme of Os/sup 189/ Evidence was found for strong rotation-particle coupling between low-lying K =1/2 and K = 3/2 bands in Os/sup 189/. 40 references. (auth)

The effect of finite resistance in the vacuum-tank walls on the longitudinal stability of an intense beam of particles in an accelerator is investigated theoretically. We show that even if the particle frequency is an increasing function of particle energy, the wall resistance can render the beam unstable against longitudinal bunching. In the absence of frequency spread in the unperturbed beam, the instability occurs with a growth rate that is proportional to (N/{sigma}){sup 1/2}, where N is the number of particles in the beam and {sigma} is the conductivity of the surface material. By means of the Vlasov equation a criterion for beam stability is obtained. In the limit of highly conducting walls the criterion involves the frequency spread in the unperturbed beam, the number of particles N, the beam energy, geometrical properties of the accelerator, but not the conductivity {sigma}. A numerical example presented indicates that certain observations of beam behavior in the MURA 40-Mev-electron accelerator may be related to the phenomenon we investigated.

A Sarcina strain (Coccus P) produces two proteolytic enzymes. One is found only extracellularly, is far more prevalent, and is actively excreted during exponential growth. It is the enzyme responsible for the known strong proteolytic activity of the cultures of this strain. A second protease is, however, produced which remains associated with the intact cells but is released by the protoplasts. The two enzymes appear unrelated in their derivation. Calcium ions play an essential role in preventing autodigestion of the excreted enzyme. Bacterial proteins are found outside the cell boundary as a consequence either of passive processes such as leakage or lysis or of active excretion. Under conditions in which leakage and lysis do not occur, as during exponential growth, the cell boundary is a barrier causing a complete separation of the bulk of the intracellular proteins from the one or very few extracellular proteins, with no trace of either type being detectable on the wrong side of the boundary. Since in bacteria there is no evidence of protein being produced other than internally, the separation into intraand extracellular proteins should occur after peptide chain formation. The question arises as to whether the structure of the cell boundary or that …

It has been known that the extracellular proteinase of Coccus P is found only in cultures grown in the presence of Ca{sup 2+}. It is now shown that this cation is required neither for synthesis, excretion, or activation of a zymogen nor as a prosthetic factor necessary for enzymatic activity. The only function of Ca{sup 2+} is to stabilize the active structure of the enzyme molecule, presumably by substituting for absence of S-S bridges. In the absence of Ca{sup 2+} , the excreted proteinase undergoes rapid autodigestion and, instead of the active protein, its hydrolytic products are accumulated in the culture fluid. In minimal medium and under conditions of enzyme stability [presence of Ca{sup 2+} and Ficoll (Pharmacia)], Coccus P accumulates the proteinase at a gradually reduced speed although the rate of cultural growth remains constant. It is shown that this decline in rate of accumulation is caused by the excreted proteinase itself, possibly acting on its own precursor emerging from the cell in a form susceptible to proteolytic attack and not amenable to Ca{sup 2+} protection. A proteinase precursor is actually demonstrable in a calciumless culture at the onset of the enzyme accumulation which follows Ca{sup 2+} addition. It …

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From national safety congress and exposition meeting; Chicago, Illinois, USA (29 Oct 1973). Results are reported from a survey of the local presidents of US Oil, Chemical, and Atomic Workers Union of the extent to which employees of research and development organizations are complying with Federal occupational safety and health standards. (CH)

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A code, CACECO, has been written to assist in the analysis of containment situations peculiar to sodium cooled reactors. Typically, these situations involve relatively slow energy release processes and chemical reaction heat. Two examples are given to illustrate some of the code's features. These particular cases illustrate the potential for hydrogen formation in the containment building, but show that time is available to take corrective action. The code is suitable for other problems involving passive heat absorption in massive structures over long periods of time.

The discovery of a very simple and useful relationship between the absorption coefficient of a particular element and the ratio of incoherent to coherent scattering by the sample containing the element is discussed. By measuring the absorption coefficients for a few elements in a few samples, absorption coefficients for many elements in an entire set of similar samples can be obtained. (auth)

The initial results of a comparative study of the radiation strengthening and damage structures produced in Cu and Nb by D-T fusion and fission reactor neutrons are described. The radiation strengthening produced by a given fluence of fusion neutrons above about 10$sup 17$ n/cm$sup 2$ is equal to that produced by a fluence of fission reactor neutrons (E greater than 0.1 MeV) ten times as great. This difference is about twice as large as would be expected if the strengthening scaled with damage energy or dpa. Initial transmission electron microscopy observations of the damage structures in fusion and fission reactor neutron irradiated copper indicate that the same type of primary structural defects, vacancy and interstitial point defect clusters and small dislocation loops with a/3 (111) and a/2 (110) Burgers vectors, are produced in both cases. The difference in the radiation strengthening produced by fusion and fission reactor neutrons in Cu appears to result from a substantially greater rate of accumulation of damage, in the form of point defect clusters, during irradiation with fusion neutrons than during irradiation with fission reactor neutrons plus a significant difference in the size and spatial distributions of the damage clusters. (auth)

The Fort St. Vrain program has progressed through construction, preoperational testing, fuel loading, initial criticality, and operational testing at power levels up to 2 percent related power. To date, all tests necessary before the rise to full power have been completed, and the rise-to- power program is expected to be resumed again in late 1975. Major plant systems, including the prestressed concrete reactor vessel and circulators, have demonstrated adequate performance. Extensive tests on the reactor core at zero power and up to 2 percent power have demonstrated the accuracy in the design predictions of such core characteristics as critical rod position, control system worths, neutron flux distributions, and temperature coefficients. Gaseous fission product release measurements to date have confirmed the extensive analytical estimates. 6 references (auth)

A unified Hamiltonian approach to the theory of nonlinear interactions among waves and particles is discussed. The unifying feature of the approach is a generalization of the concept of pondermotive force. The usual method of time averaging is replaced by a canonical transformation. The transformation is designed to eliminate the terms in the Hamiltonian of a particle which are linear in the wave potentials, replacing them with bilinear terms at combination frequencies. An oscillation center approach is illustrated by deriving a compact general formula for the three-wave coupling coefficient in collisionless plasma. (MOW)

A small man-portable neutron detector was constructed using 18 /sup 3/He proportional counters arranged in three layers within a polyethylene moderator. Each counter is 25 mm in diameter by 340 mm long (sensitive length) and is filled with highly-purified /sup 3/He to a pressure of 400 kPa (4 atm). Efficiency measurements were made using a /sup 252/Cf neutron source. Detailed calculations of the detector efficiency were done using the TART Monte Carlo transport code. Calculations and measurements were compared for several source/detector configurations.

A Digital Equipment Corporation PDP-14 Industrial Programmable Controller was employed to provide automatic, closed-loop control for an explosive pellet manufacturing system at Mound Laboratory. Programmable controllers allow the application of sophisticated and flexible control, through programming. Advantages of the PDP-14 controller are ease of installation and maintenance, capability for modular expansion, and immunity to electrical noise. Safety requirements were met by using new techniques for adapting electrical equipment to a hazardous environment and by locating the PDP-14 remotely outside the explosive area. Another advantage of the new explosion proofing (EP) methods/equipment was that they produced a minimum of clutter on the controlled explosive pellet manufacturing system.

The design, development, and implementation of a document information system at LASL is described. This system combines microfilm technology with a System 2000 computer. 14 figures (RWR)

A coil winder was designed for the purpose of fabricating the superconducting magnets of the Mirror Fusion Test Facility. The superconducting magnets are a displaced ying-yang pair, each having major and minor radii of 2.5 and 0.75 m, respectively, and cross section of 0.42 m by about 1.03 m. The superconductor cross section is a square, 13 mm on a side, and consists of a core of niobium-titanium embedded copper and a solid copper stabilizer. Conceptual studies made at Lawrence Livermore Laboratory of the coil winder resulted in concept drawings and a procurement specification. Final design was made by the contractor, and the coil winder is now in fabrication. This paper describes the performance requirements of the winder, and the evolution of its design from conceptual stage to completion.

Glazed pottery known as ''Afrasiyab'' and ''Nishapur'' wares (early Islamic ceramics) are generally attributed to the Samanid dynasty (819-1005). The clay composition of Samanid wares and discarded kiln items found in situ were analyzed by NAA and the elemental composition compared with that of other sherds. 7 figures, 1 table. (DLC)

Apparatus is described for rapidly manipulating a hollow glass microsphere laser fusion target and scanning the entire wall with a double pass interference microscope.