Pb-Zn liquid metal diffusion

The Lead-Zinc binary equilibrium system is currently being investigated. Ground based studies of this system were performed to examine the possibility of obtaining a couple which, after diffusion, could be examined continuously along the diffusion axis by quantitative metallography to determine the extent of diffusion. The specimens were analyzed by X-ray fluorescence in the scanning electron microscope to provide exact information on the chemical composition gradient. Two diffusion experiments were run simultaneously in the multipurpose furnace, each in its own isothermal cavity. Two flight samples, two flight backup samples, and two flight space samples were generated

Shoulder Arms : Marche Militaire

https://digitalcommons.library.umaine.edu/mmb-ps/2618/thumbnail.jp

Discrete Event Simulation of Distributed Team Communication Architecture

As the United States Department of Defense continues to increase the number of Remotely Piloted Aircraft (RPA) operations overseas, improved Human Systems Integration becomes increasingly important. RPA systems rely heavily on distributed team communications determined by systems architecture. Two studies examine the effects of systems architecture on operator workload of US Air Force MQ-1/9 operators. The first study ascertains the effects of communication modality changes on mental workload using the Improved Research Integration Pro (IMPRINT) software tool to estimate pilot workload. Allocation of communication between modalities minimizes workload. The second study uses IMPRINT to model Mission Intelligence Controllers (MICs) and the effect of the system architecture upon them. Four system configurations were simulated for four mission activity levels. Mental workload, monitoring time and the number of delayed tasks were estimated to determine the effect of changing system architecture parameters. Literature and MIC interviews provided parameters for the model. The analysis demonstrates that the proposed changes have significant effects which, in some conditions, bring the overall workload function toward a proposed theoretical optimum

Thermal and convection analyses of the dendrite remelting rocket experiment; Experiment 74-21 in the space processing rocket program

The Dendrite Remelting Rocket Experiment was performed aboard a Black Brant VC Sounding Rocket during a period which gravity levels of approximately 0.00001 g prevailed. The experiment consisted of cooling an aqueous ammonium chloride solution in a manner such that crystallization of ammonium chloride crystals proceeded throughout a three minute period of zero-g. The crystallization process during flight was recorded on 35 mm panatomic-x film. A number of ground crystallizations were similarly recorded for comparison purposes. The convective and thermal conditions in aqueous and metallic liquid systems were assessed under conditions of the flight experiment to help establish the relevance of the rocket experiment to metals casting phenomena. The results indicate that aqueous or metallic convective velocities in the Dendrite Remelting Rocket Experiment cell are of insignificant magnitudes at the 0.0001 to 0.00001 g levels of the experiment. The crystallization phenomena observed in the Rocket Experiment, therefore, may be indicative of how metals will solidify in low-g

Spinal Cord Ischaemia Following Endovascular Repair of Abdominal Aortic Aneurysm: Result of Spinal Drain Insertion in a Rare Complication

IntroductionSpinal cord ischaemia (SCI) is a devastating complication of endovascular abdominal aortic aneurysm repair (EVAR), with a reported incidence of 0.2%. Interventions for SCI are largely derived from thoracic and thoracoabdominal aortic repairs.ReportWe report a case of acute neurological injury complicating an EVAR that was altered by spinal drain insertion and removal.DiscussionThis case highlights the need for appropriate consent of EVAR patients and the early utilisation of a spinal drain in the management of SCI

The Sommerfeld half-plane problem revisited, IV: Variations on a theme of Carlson and Heins

A plane wave is incident upon an infinite set of equally spaced, semi-infinite parallel and staggered plates. The boundary conditions on the plates alternate between the Dirichlet and Neumann ones. This problem is formulated as a pair of coupled Wiener-Hopf integral equations and solved by a method proposed by A. E. Heins in 1950. For the case of specular reflection, that is, a single reflected plane wave, the magnitudes of the reflection coefficient and the transmission coefficients are determined.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50172/1/1670100307_ftp.pd

Cheminement des carrières de direction dans la fonction publique au Canada

Cet article présente un résumé d'une étude entreprise auprès des hauts fonctionnaires dans la fonction publique du Canada. Elle porte sur le cheminement des carrières et touche aussi à la mobilité, à l'occupation et aux sources de recrutement.Who are the most capable executives in the Federal Public Service ? What are their experience characteristics ? How mobile have they been ? What are their academic backgrounds ? How does age relate to seniority and earning power ?These and related questions must be answered if manpower at upper government levels is to be managed more effectively.A fourteen-month study recently completed by the Personnel Consulting Division, Bureau of Management Consulting Services, Ottawa, has made a major contribution towards providing these answers.In the Public Service of Canada, at the time the study was made in July, 1965, there were some 625 executives with salaries ranging from $16,000 to$30,000. These are the men and women who fill the top three or four levels in each department or agency. Officially, they are known as Senior Officers 1, 2, 3. and Deputy Ministers (Deputy Heads).Data on 591 of these executives was obtained from files and various other sources, coded and fed into a Bendix G-20 computer along with some 40 questions, the answers to which provided the following information :The typical executive is 51 years old and probably has a B.A. in Social Management Sciences (Arts, History, Political Science, Commerce, Sociology, etc.). While he could have graduated from any university in any province, the chances are greatest that he obtained his degree from the University of Toronto. He has had military service, reads a second language and joined the Public Service at a junior managerial level at 34 years of age, after having worked outside the Public Service for 11 years.At the time of his appointment to the executive level, he was 46 years of age and had 23 years of working experience. As of July 1, 1967, he had 28 years working experience and was earning $21,000 a year.BASIC PERSONAL DATAIn considering the personal data in more detail, it was found that ages ranged from 30 to 69, with an average age of 51.2. The average ages for the four levels (Senior Officer 1, 2, 3, and Deputy Minister — Deputy Head), were 50.3 52.6, 51.7 and 54.9 years respectively. The similarity of the averages implies career progression problems and also highlights the serious executive replacement problem the government faces in the next 10-15 years.A relatively high level of education was found among the government's top executives. 81$14,000 plus). Close to 20% entered directly at the executive level.SALARYAs of July 1, 1967, the average executive in the Public Service of Canada was earning $20,927 a year.It should be noted that this is a total figure because Public Servants do not receive bonusses or stock options, and there is not profit to be « profit-shared ».For the three career path categories they were :Public Service Only$21,297Private-Public 20,861Public-Private-Public 20,862Subsequent to this study, the government released proposed salary scales for the executive levels ranging from a maximum of $23,500 for Senior Executive Officers 1 up to a maximum of$40,000 for certain Deputy Ministers.APPOINTMENT TO EXECUTIVE LEVELThe average age at time of appointment to the Senior Officer 1 level was 45.6, to the SO 2 level 48, SO 3 level 47 and DM-DH 52. The similarity of these figures is interesting, since one would expect an executive to progress from the lowest to highest level. Also, based on today's standards, the ages would appear to be rather high.TRENDS IN AGE AT APPOINTMENTIt is generally believed that there has been a trend to appoint younger officers to the executive levels, but the study casts some doubt on the belief, certainly as far as government is concerned. However, more recent data obtained since the completion of the study indicates a change in the trend with the average ages of Senior Officers 1 appointed in 1966, 1967 and 1968, decreasing from 48 to 46 to 43 years respectively.EXPERIENCEThe average government executive has 28 years experience, almost two-thirds of which will have been spent in the Public Service. He will have spent about 15% in the category we called « Business and Self-Employed » and 10% in military service.However, there were indications that the more time executives spent in industry the less capable they were of adjusting to the political and Public Service atmosphere. Similarly it was found that extended career military service tended to reduce the rate of progress.RECRUITMENTPrior to July, 1967, about 76% of all appointments to the executive level were made from within the individuals present department and about 9% were from other departments. Therefore, some 85% of all appointments were from within the Public Service. Of the remaining 15%, some 10% came from Industry and 5% were recruited from Provincial Governments (2.4%), Universities (1.5%) and the Armed Forces (.3%).MOBILITYWithin the Public Service, a great interest has recently developed in the movement, or lack of movement, of management level personnel from one department to another. Traditionally, Public Servants have tended to remain in one department, rising to senior levels within what many claim to be a narrow occupational field.From the findings it appeared that moving from one department to another, within the Public Service, tended to improve the possibilities of achieving more rapid progress.A further analysis of movement after reaching the executive level showed that slightly more than 12% of all executives changed departments at least once after reaching this level and 1.3% had changed twice. This figure is changing rapidly as over 30% of the appointments made in 1968, at the executive level, resulted in movement between departments

Composition and concentration anomalies for structure and dynamics of Gaussian-core mixtures

We report molecular dynamics simulation results for two-component fluid mixtures of Gaussian-core particles, focusing on how tracer diffusivities and static pair correlations depend on temperature, particle concentration, and composition. At low particle concentrations, these systems behave like simple atomic mixtures. However, for intermediate concentrations, the single-particle dynamics of the two species largely decouple, giving rise to the following anomalous trends. Increasing either the concentration of the fluid (at fixed composition) or the mole fraction of the larger particles (at fixed particle concentration) enhances the tracer diffusivity of the larger particles, but decreases that of the smaller particles. In fact, at sufficiently high particle concentrations, the larger particles exhibit higher mobility than the smaller particles. Each of these dynamic behaviors is accompanied by a corresponding structural trend that characterizes how either concentration or composition affects the strength of the static pair correlations. Specifically, the dynamic trends observed here are consistent with a single empirical scaling law that relates an appropriately normalized tracer diffusivity to its pair-correlation contribution to the excess entropy.Comment: 5 pages, 4 figure