The Adsorption of Certain Vapors by Activated Charcoal

Isotherms for the adsorption of ethane, propane, dimethyl ether and diethyl ether by activated charcoal were obtained at temperatures from 0° to 183° and at pressures varying from less than l mm. to about 1 atm. With the hydrocarbons equilibrium was attainable only after long periods of time. The isotherms for the hydrocarbons are in general almost rectilinear; those for the ethers have the usual form. At low temperatures the isotherms for the hydrocarbons show a peculiar type of break in the curve. The amount of vapor adsorbed decreases with an increase in the complexity of the adsorbed molecules. Semi-log isotherms, double-log isotherms, isobars and isosteres were calculated from the natural isotherms. The heat of adsorption was calculated from the slope of the isosteres

Maximally entangled mixed states: Creation and concentration

Using correlated photons from parametric downconversion, we extend the boundaries of experimentally accessible two-qubit Hilbert space. Specifically, we have created and characterized maximally entangled mixed states (MEMS) that lie above the Werner boundary in the linear entropy-tangle plane. In addition, we demonstrate that such states can be efficiently concentrated, simultaneously increasing both the purity and the degree of entanglement. We investigate a previously unsuspected sensitivity imbalance in common state measures, i.e., the tangle, linear entropy, and fidelity.Comment: 4 pages, 3 figures, 1 table; accepted versio

Cp* Noninnocence Leads to a Remarkably Weak C–H Bond via Metallocene Protonation

Metallocenes, including their permethylated variants, are extremely important in organometallic chemistry. In particular, many are synthetically useful either as oxidants (e.g., Cp_2Fe^+) or as reductants (e.g., Cp_2Co, Cp*_2Co, and Cp*_2Cr). The latter have proven to be useful reagents in the reductive protonation of small-molecule substrates, including N_2. As such, understanding the behavior of these metallocenes in the presence of acids is paramount. In the present study, we undertake the rigorous characterization of the protonation products of Cp*_2Co using pulse electron paramagnetic resonance (EPR) techniques at low temperature. We provide unequivocal evidence for the formation of the ring-protonated isomers Cp*(exo/endo-η^4-C_5Me_5H)Co^+. Variable temperature Q-band (34 GHz) pulse EPR spectroscopy, in conjunction with density functional theory (DFT) predictions, are key to reliably assigning the Cp*(exo/endo-η^4-C_5Me_5H)Co^+ species. We also demonstrate that exo-protonation selectivity can be favored by using a bulkier acid and suggest this species is thus likely a relevant intermediate during catalytic nitrogen fixation given the bulky anilinium acids employed. Of further interest, we provide physical data to experimentally assess the C–H bond dissociation free energy (BDFE_(C–H)) for Cp*(exo-η^4-C_5Me_5H)Co^+. These experimental data support our prior DFT predictions of an exceptionally weak C–H bond (<29 kcal mol^(–1)), making this system among the most reactive (with respect to C–H bond strength) to be thoroughly characterized. These data also point to the propensity of Cp*(exo-η^4-C_5Me_5H)Co to mediate hydride (H–) transfer. Our findings are not limited to the present protonated metallocene system. Accordingly, we outline an approach to rationalizing the reactivity of arene-protonated metal species, using decamethylnickelocene as an additional example

A Configuration Management and Monitoring Toolkit for EOS and Kinetic Drive Cluster

Abstract EOS is a simple storage software solution to manage multi PB storage at CERN. Seagate ki Abstract EOS is a simple storage software solution to manage multi PB storage at CERN. Seagate kinetic drives have been interfaced with the CERN EOS disk storage system abstracting multiple drives as a cluster. Drive cluster are managed by EOS like a single storage mount point. Each drive cluster, access keys and the cluster layout is described in a JSON file. Monitoring EOS and managing configuration files for thousands of disks was inefficient. This project aimed at the development of a web toolkit for configuration management and monitoring of thousands of kinetic drives and EOS via a simple web interface. The proposed application allows to define, modify and publish kinetic drive cluster configurations and to monitor key statistics and individual drive parameters on demand. In this report, I cover how I went about building this toolkit. Keywords: EOS, Configuration Management, Monitor, Kinetic Drives, AngularJS, Drive clus-ter, CERN storage, Seagate, Performance Optimization -netic drives have been interfaced with the CERN EOS disk storage system abstracting multiple drives as a cluster. Drive cluster are managed by EOS like a single storage mount point. Each drive cluster, access keys and the cluster layout is described in a JSON file. Monitoring EOS and managing configuration files for thousands of disks was inefficient. This project aimed at the development of a web toolkit for configuration management and monitoring of thousands of kinetic drives and EOS via a simple web interface. The proposed application allows to define, modify and publish kinetic drive cluster configurations and to monitor key statistics and individual drive parameters on demand. In this report, I cover how I went about building this toolkit. Keywords: EOS, Configuration Management, Monitor, Kinetic Drives, AngularJS, Drive clus-ter, CERN storage, Seagate, Performance Optimizatio

Potential Failure of A Decayed Tree Under Wind Loading

Trees with decayed wood that are subject to moderate winds often collapse and cause property damage or injury and death to people. The purpose of this paper is to describe a decision-making aid to help identify a tree that may fail in the forest or be a potential hazard in the city. A tree may fail when the probability of radial shear cracks developing for a given wind load is sufficiently high.Mathematical models are used to estimate the constant wind force on trees and to evaluate the cracking and collapse mechanisms under this loading. The physical dimensions are used to determine the wind force or drag on the tree, and the amount of decay in the tree is used to determine its ability to resist this load. Owing to uncertainties associated with accurately measuring and modeling a decayed tree, estimating the wind load, and specifying the wood strength of a tree species, reliability analysis is used to assess the potential risk of failure. Coupling this information with meteorological data for the largest wind speed value expected at the tree site and the topography of the tree site completes the analysis of potential failure. Case studies of balsam fir trees with the same exterior diameters but with different dimensions of decay columns, tree weights, tree heights, and wind speed conditions are analyzed and compared

Book Reviews

Book reviews by Roger Paul Peters, David Bidney, Lester M. Ponder, Edward J. Murphy, Thomas M. Clusserath, and Thomas L. Shaffer

Rational modification of an HIV-1 gp120 results in enhanced neutralization breadth when used as a DNA prime

Background The identification of phenotypic features of the HIV-1 envelope glycoprotein that correlate with neutralization breadth is an important goal of HIV vaccine research. Recently we compared the immunogenic potential of two gp120s differing in their ability to utilize CD4; B33 (highly macrophage topic) and LN40 (non-macrophage tropic). Using a DNA prime protein boost regimen in New Zealand White Rabbits, LN40-primed sera displayed enhanced breadth compared to the B33-primed group, with differences in immunogenicity between groups modulated by specific residues within and flanking the V3 loop and the CD4bs. To better understand the role of these residues in eliciting breadth, we introduced reciprocal mutations between LN40 and B33 at these critical positions. Methods Three groups of four rabbits were primed with one of three chimeric LN40/B33 gp120 DNAs, followed by a polyvalent protein boost. Time course and endpoint titers were determined via ELISA. Neutralization breadth was analyzed by Monogram against a panel of sixteen viruses using a Phenosense neutralization assay. Anti-gp120 serum specificities were determined using a set of overlapping peptides spanning the entire gp120 via ELISA. Results We found that sera primed with a B33 chimera containing specific LN40 residues within the V3 loop and the CD4 binding loop displayed enhanced neutralization breadth against a cross-clade panel of Tier 1 and 2 viruses compared to the B33-primed group. Interestingly, a second B33 chimera containing two additional LN40 substitutions (Stu-Bsu R373/N386) within C3/V4 primed the broadest response, being broader than even the LN40-primed group. Additionally, peptide ELISAs showed differences in reactivity between priming groups which were most pronounced for the C3/V4 region, suggesting an important role for these regions in modulating serum antibody responses against gp120