Heavy ion plasma confinement in an RF quadrupole trap

The confinement of an electron free plasma in a pure quadrupole RF electric trap was considered. The ultimate goal was to produce a large density of mercury ions, in order to realize a trapped ion frequency standard using the hyperfine resonance of 199 Hg(+) at 40.7 GHz. An attempt was made to obtain an iodine plasma consisting of equal numbers of positive and negative ions of atomic iodine, the positive iodine ions, being susceptible to charge-exchange with mercury atoms, will produce the desired mercury ions. The experiment showed that the photoproduction of ions pairs in iodine using the necessary UV radiation occurs with a small cross-section, making it difficult to demonstrate the feasibility of space charge neutralization in a quadrupole trap. For this reason it was considered expedient to choose thallium iodide, which has a more favorable absorption spectrum (in the region of 2000 to 2100 A). The results indicate that, although the ionic recombination is a serious limiting factor, a considerable improvement can be obtained in practice for the density of trapped ions, with a considerable advantage in lifetimes for spectroscopic purposes. The ion pair formation by photoionization is briefly reviewed

The Electrostatic Ion Beam Trap : a mass spectrometer of infinite mass range

We study the ions dynamics inside an Electrostatic Ion Beam Trap (EIBT) and show that the stability of the trapping is ruled by a Hill's equation. This unexpectedly demonstrates that an EIBT, in the reference frame of the ions works very similar to a quadrupole trap. The parallelism between these two kinds of traps is illustrated by comparing experimental and theoretical stability diagrams of the EIBT. The main difference with quadrupole traps is that the stability depends only on the ratio of the acceleration and trapping electrostatic potentials, not on the mass nor the charge of the ions. All kinds of ions can be trapped simultaneously and since parametric resonances are proportional to the square root of the charge/mass ratio the EIBT can be used as a mass spectrometer of infinite mass range

A sock for foot-drop: A preliminary study on two chronic stroke patients

Background: Foot-drop is a common motor impairment of chronic stroke patients, which may be addressed with an ankle foot orthosis. Although there is reasonable evidence of effectiveness for ankle foot orthoses, user compliance is sometimes poor. This study investigated a new alternative to the ankle foot orthosis, the dorsiflex sock. Case description and methods: The dorsiflex sock was evaluated using an A-B single case experimental design. Two community-dwelling, chronic stroke patients with foot-drop participated in this study. Measures were selected to span the International Classification of Function, Disability and Health domains and user views on the dorsiflex sock were also collected. Findings and outcomes: The dorsiflex sock was not effective in improving participants’ walking symmetry, speed or energy expenditure. Participant 1 showed improvement in the distance he could walk in 6 min when using the dorsiflex sock, but this was in keeping with a general improvement trend over the course of this study. However, both participants viewed the dorsiflex sock positively and reported a positive effect on their walking. Conclusion: Despite positive user perceptions, the study found no clear evidence that dorsiflex sock is effective in improving foot-drop. Clinical relevance Although the dorsiflex sock offers an attractive alternative to an ankle foot orthosis, the case studies found no clear evidence of its efficacy. Clinicians should view this device with caution until further research becomes availabl

A Modern Army Reserve for a Multi-Domain World: Structural Realities and Untapped Potential

Since its inception in 1908, the US Army Reserve has made important, diverse, and cost-effective contributions to our nation while demonstrating the ability to adapt to meet emerging requirements. The emerging complex threats in today’s strategic and operational environments require the Army Reserve to adapt again.https://press.armywarcollege.edu/monographs/1371/thumbnail.jp

International Military Acquisitions Program Model : A Game Theory Approach

The nations of the world spend a signifi cant portion of their wealth on militaries. Every year,billions of dollars go to recruiting, training, maintaining, and equipping the men and women who serve their countries in uniform. This paper looks into one aspect of military spending, acquiring new equipment and systems. In particular, the research focuses on international cooperation in weapon system development and proposes a model to aid decision makers to decide whether and when to join a joint development program. The main goal is to determine what factors are most important in choosing military acquisitions program partners and then to create a model using those factors that will produce policy recommendations for program cooperation

Relations and evolution in "Cheilanthes" ("Sinopteridaceae, Pteridophyta") in Macaronesia and Mediterranean area, deduced from genome analysis of their hybrids

Nine species of "Cheilantoid ferns" are known to grow in Macaronesia and the Mediterranean basin. Two of them (lacking a pseudo-indusium and having the basic chromosome number X = 29), both aggregate species which we prefer to retain in Notholaena, are not included in this study. The other seven species (with distinct pseudo-indusium and the basic chromosome number X = 30), which we accept as members of the genus Cheilanthes Sw. sensu stricto, were subjected to detailed genome analysis of their natural and experimentally produced hybrids and shown to represent an aggregate of four very distinct ancestral diploids and three allotetraploids. The latter must have once been formed by chromosome doubling in the three diploid hybrids of C. maderensis Lowe with the other three diploid species. Theoretically three more allotetraploids would be possible but their formation has obviously been prevented by the geographical separation of the three respective diploids. The most widely distributed of the tetraploids, i.e. C. pteridioides (Reich.) C.Chr. has also been resynthesized from its ancestors (still sympatric) under experimental conditions. The intermediate morphology of the allotetraploids (as compared with their diploid ancestors) is obviously the reason why their status and existence has so long escaped recognition in Europe. These seven species form a natural group and, in our opinion, should not be divided into sections.Se conocen nueve especies de "helechos Cheilantoides" que viven en Macaronesia y la cuenca Mediterranea. Dos de ellos, (sin pseudoindusio y con número cromosómico básico X = 29) que preferimos incluir en Notholaena, no se estudian en este trabajo. Las otras siete especies (con pseudoindusio y número cromosómico básico X = 30) que reconocemos como miembros del género Cheilanthes Sw. sensu stricto, fueron objeto de un análisis detallado del genoma de sus híbridos, tanto de los naturales, como de los producidos experimentalmente mostrando un agregado de cuatro ancestrales diploides muy distintos y tres alotetraploides. Estos últimos deben haberse formado por duplicación de los cromosomas en los tres híbridos diploides resultantes del cruzamiento de C. maderensis con las otras tres especies diploides. Teóricamente son posibles otros tres alotetraploides, pero su formación se ha impedido por la separación geográfica de los 3 diploides respectivos. Los tetraploides más ampliamente distribuidos, como por ejemplo Cheilanthes pteridioides (Reich.) C. Chr., han sido igualmente resintetizados a partir de sus ancestros bajo condiciones experimentales. La morfología intermedia de los alotetraploides (comparada con sus ancestros diploides) es obviamente la razón por la que su existencia y status han pasado inadvertidos en Europa. Estas siete especies forman un grupo natural que, en nuestra opinión, no debe ser dividido en secciones

Design and Construction of A 50kg Capacity Furnace

The design and development of a 50Kg charcoal fired crucible furnace for melting aluminium and its alloys are presented. Importance of Metal melting furnaces cannot be overemphasized in industrialized and under industrialized countries. A detailed designed analysis was conducted to determine the various component sizes of the crucible furnace so to pave way for its construction. Majority of the materials used for the furnace construction were obtained locally. The blower capacity was determined to be air to ratio of 400:1 and 0.05m3/min. The designed furnace of overall volumetric capacity of 0.57m3 accommodates a crucible pot which had a height and volume of 0.577m and 0.0155m3 respectively. The designed operating temperature of the furnace was 1200oC and maintained a heat transfer rate of 494.2W/m2 across the wall. The designed efficiency of the charcoal fired furnace was 59.35%. Keywords: Crucible, furnace, Charcoal, Volumetric capacity, Design, Efficiency DOI: 10.7176/ISDE/12-2-03 Publication date: April 30th 202

Internal Geometry of a Modern Carbonate Grainstone Shoal--an Analog for Hydrocarbon Reservoir Heterogeneity

We chose the ooid sand shoals of the Joulters Cays area of Great Bahama Bank for detailed sedimentological study to investigate the patterns of internal heterogeneity within a modern carbonate sand belt and to develop criteria for predicting the lateral extent of carbonate sand facies. Major facies identified from cores were (1) crossbedded, well-sorted ooids, (2) burrowed, poorly sorted ooids, and (3) poorly sorted ooids and mud containing Thalassia. Clast-rich zones and mud layers were also encountered. We propose that upon burial and compaction, the poorly sorted ooids and mud containing Thalassia will likely retain negligible porosity and permeability, whereas both the crossbedded, well-sorted ooids and burrowed poorly sorted ooids will likely maintain their high initial porosity and permeability. However, study of many ancient subsurface reservoirs indicates that the crossbedded, well-sorted ooids can undergo considerable cementation and have low resultant porosity and permeability. Thus, in many settings, the burrowed, poorly sorted ooids could retain the highest porosity and permeability. Additional cementation within the clast-rich zones, which occur in both the crossbedded, well-sorted ooids and burrowed, poorly sorted ooids, will result in thin, low-porosity barriers within a reservoir. Locally the surface configuration of the modern shoal complex at Joulters Cays was altered significantly by the passing of Hurricane Andrew in August 1992. Prominent wash over bars were planed off, and well-sorted ooids were deposited in low areas of the shoal where poorly sorted and mud-rich deposits of ooids had previously accumulated. The post-hurricane configuration of the shoal demonstrates how a single short-term depositional event contributed significantly to the internal heterogeneity of the shoal complex.Bureau of Economic Geolog