Some Chemical Reactions in Silica Gels II. Formation of Crystals of a Basic Mercuric Chloride, HgCl2-2HgO1

Author Institution: Battelle Memorial Institute, Columbus, Ohio 43201This investigation was concerned with a study of some factors which control the formation of HgCU^HgO crystals in silica gels. It is possible to control the size, shape, color, rate of growth, and distribution of crystals of this basic salt by varying the initial alkalinity of the gel, the silica content of the gel or the rate of infusion of HgCl2 into the gel. The level in a gel at which HgCU^HgO crystal start to grow can be controlled readily by adding H+ to the HgCU used as external reactant. Evidence is presented to show that the basic salt is HgCl2-2Hg0 and not a more basic or a less basic mercuric chloride

Some Chemical Reactions in Silica Gels : III. Formatin of Potassium Acid Tartarate Crystals

Author Institution: Battelle Memorial Institute, Columbus Laboratories, Columbus, OhioThis work was concerned with investigating methods for growing potassium acid tartrate (KHT) crystals by chemical reaction in acidic gels prepared with tartaric acid (H2T) and sodium silicate and reacted with K+. H2T ranging from IN to 18N was used, and remarkable changes in size and perfection of shape of KHT crystals formed were noted as the concentration of H2T was increased. Gels made with H2T to 6N in strength permitted growth of mostly imperfect rhombohedra, some quite elongated and practically all veiled. Gels made with 8N, ION, 15N, and 18N H2T favored formation of clear, nonveiled, essentially perfectly shaped rhombohedra. KC1, KBr, KNO3, and K2SO4 appear equally useful as external reactants. KI permits growth of excellent crystals also, but forms HI, which reduces tartrate progressively to malate and succinate, releases I2, and produces an increasingly intense background color. K2Cr04 consumes tartrate in redox and prevents KHT formation. Potassium acetate causes gel cleavage and produces multitudes of clusters of tiny needles

Some Chemical Reactions in Silica Gels. I, Formation of Mercuric Iodide Crystals

Author Institution: Battelle Memorial Institute, Columbus, OhioThis investigation was concerned with reactions which form Hgl2 in acidic gels prepared with acetic acid and sodium silicate. The results of this work support the postulation that the yellow crystal frontal zone which advances through the gel as reaction progresses is probably the yellow polymorph of Hgl2 and not a complex alkali metal mercuri-iodide. In addition, the results show that mercuric chloride reacts with iodine in acidic gels to form Hgl2. A plausible reaction scheme involving enhancement of I2 hydrolysis and enhancement of the disproportionation of HOI by the presence of Hg++ appears to explain this unanticipated behavior

Reactions Between Pb2+ and (I-+I3) in Acidic Silica Gels

Author Institution: Battelle Memorial Institute, Columbus, Ohio 43201In this work it was found that reactions between Pb2+ and (I-+I3-) in acidic silica gels are limited to the formation of Pbl2 from Pb2++2 I- and from Pb2++2I J , the latter occurring with the coincident formation of I2 crystals. There was no evidence of pseudomorphic conversion of I2 to Pbl2, even by the presence of large excesses of Pb2+, in contrast to reactions in acidic gels between excess Hg2+, Ag+, or Tl+ and I2, in which instances these metal cations convert I2 pseudomorphically to the respective iodides. When a deficiency of Pb2+ existed, there was no zone separation of Pbl2 and I2, as occurs with Hgl2, Agl, or Til and I2 in metal-ion deficient systems, and the distributions of Pbl2 and I2 crystals were random

The design of the HOM-damping cells for the S-band linear collider

Damping cells for the higher order modes are necessary for the S-band linear collider to minimize BBU (Beam-Break-Up). The construction of the damper cells has to take into account the different field geometries of the higher order modes. So two different types of dampers have been designed: a wall slotted an an iris slotted cell. In order to optimize the two types of damping cells with respect to damping strength, impedance matching between coupling system and waveguide dampers and between damping cell and undamped cells and the tuning system, damping cells of both types have been built and examinated

The effect of a single HOM-damper cell within a channel of undamped cells

The effect of a single HOM-damper cell within a channel of undamped cells is described theoretically using an equivalent circuit model. From this a simple equation can be derived which relates the Q-value of the single damping-cell, the bandwidth of the passband under consideration, and the additional phase shift which is introduced by the damper cell to provide energy flow into the damper cell. This equation immediately shows the limitations of such single cell damping systems. Comparisons with experimental results are shown

Demand for Medical Care by the Elderly: A Nonparametric Variational Bayesian Mixture Approach

Outpatient care is a large share of total health care spending, making analysis of data on outpatient utilization an important part of understanding patterns and drivers of health care spending growth. Common features of outpatient utilization measures include zero-inflation, over-dispersion, and skewness, all of which complicate statistical modeling. Mixture modeling is a popular approach because it can accommodate these features of health care utilization data. In this work, we add a nonparametric clustering component to such models. Our fully Bayesian model framework allows for an unknown number of mixing components, so that the data, rather than the researcher, determine the number of mixture components. We apply the modeling framework to data on visits to physicians by elderly individuals and show that each subgroup has different characteristics that allow easy interpretation and new insights

Mode propagation in an iris type accelerator section loaded with single heavily HOM-damped cells

The wakefield effects in accelerator sections for future linear colliders will be reduced either by damping by detuning or by a combination of both. For the DESY/THD linac [1] it is forseen to employ heavily HOM-damped cells to provide a strong coupling to the TE/TM11-dipole passband as well as to the TM/TE11-dipole passband. For our experiments we have used wall-slotted damping cells. This leads to several problems concerning the propagation of fundamental and HOM-modes. Experimental investigations have been done. Results are presented