Thermodynamics of dissolving and solvation processes for benzoic acid and the toluic acids in aqueous solution

Experimental data are presented for the solubility in water of benzoic and toluic acids from 5° to 65°C. From the solubility the molality of the monomeric form of the acid is calculated using literature data for both ionization and dimerization of the acid. These data for the monomer combined with data from the literature for vaporization of the solid and ionization in both the gas phase and the aqueous phase yield entropy and enthalpy changes for the solvation of molecular and anionic forms of the acid. A similar procedure is also applied to literature data for the solubility of benzene in water. It is shown that the hydration entropies of the monomeric forms are a linear function of their partial molar volumes. It is concluded that hydration of the undissociated o-toluic acid may be crucial to the increased acidity of that acid compared to benzoic acid.     

Measurements of the infrared absorption cross-sections of HCFC-141b (CH3CFCl2)

Detection of atmospheric trace gases by optical remote sensing techniques relies on the availability of molecular absorption spectra over a range of relevant temperatures. Absorption cross-sections of a pure vapour of the hydrochlorofluorocarbon HCFC-141b are reported at a resolution of 0.02 cm^?1 for a range of temperatures between 223 and 283 K and a spectral range of 570–3100 cm^?1. The integrated intensities of the nine main harmonic bands compare well with the data available from previous experimental studies and with theoretical calculations by ab initio and density functional theories.     

Investigations into beam monitors at the AEg ̄ IS experiment

Detailed diagnostic of antiproton beams at low energies is required for essentially all experiments at the Antiproton Decelerator (AD), but will be particularly important for the future Extra Low ENergy Antiproton ring (ELENA) and its keV beam lines to the different experiments. Many monitors have been successfully developed and operated at the AD, but in particular beam profile monitoring remains a challenge. A dedicated beam instrumentation and detector test stand has recently been setup at the AE \(\bar {g}\) IS experiment (Antimatter Experiment: Gravity, Interferometry, Spectroscopy). Located behind the actual experiment, it allows for parasitic use of the antiproton beam at different energies for testing and calibration. With the aim to explore and validate different candidate technologies for future low energy beam lines, as well as the downstream antihydrogen detector in AE \(\bar {g}\) IS, measurements have been carried out using Silicon strip and pixel detectors, a purpose-built secondary emission monitor and emulsions. Here, results from measurements and characterization of the different detector types with regard to their future use at the AD complex are presented.     

Turbulence measurements from a plane air jet with buoyancy induced curvature

An experimental investigation of the turbulence structure of a heated plane air jet discharged at various angles into quiescent surroundings is described. Hot-wire anemometry was used to obtain the profiles of mean and turbulent velocities and temperature normal and tangential to the curved path of the flow. Measurements in the buoyancy induced curved region of the jet show the relative influence of the stability induced by both buoyancy and jet curvature on the turbulence structure.     

A measurement of the charge asymmetry in the decay η → π+π−πo

An experiment has been carried out at the Rutherford Laboratory to look for a possible asymmetry in the eta decay to three pions. Eta mesons were produced in the process π^?p→ ηn. The experiment produced 165311 decays η → π⁺π^?π^o from which we determined a value for the charge asymmetry A = (0.0028 ± 0.0026). We see no evidence for C-violation in this decay.     

Analysis of co-aggregation of cancer based on registry data

OBJECTIVE: An exploratory analysis of co-aggregation of cancers using registry-based data. METHODS: We utilized sibships from over 18,000 families who had been recruited to the NCI-sponsored multi-institutional Cancer Genetics Network. The analysis assesses co-aggregation at the individual and family level and adjusts for ascertainment. RESULTS: We found statistically significant familial co-aggregation of lung cancer with pancreatic (adjusted p < 0.001), prostate (adjusted p < 0.003), and colorectal cancers (adjusted p = 0.004). In addition, we found significant familial co-aggregation of pancreatic and colorectal cancers (adjusted p = 0.018), and co-aggregation of hematopoietic and (non-ovarian) gynecologic cancers (adjusted p = 0.01). CONCLUSION: This analysis identified familial aggregation of cancers for which a genetic component has yet to be established.     

Temperature-dependent absorption cross-sections of HCFC-142b

Following the recent detection of HCFC-142b (1-chloro-1,1-difluoroethane) from space, laboratory infrared absorption cross-section spectra of this molecule in a pure vapour phase have been recorded in the spectral region using Fourier transform spectroscopy. The spectra have been recorded at a resolution of and a range of temperatures from 223 to 283 K. The resulting data show good agreement with the harmonic frequencies and intensities calculated using density functional theory as well as with the integrated absorption intensities of the spectral bands available in the literature. The new cross-sections will allow more accurate retrieval of atmospheric HCFC-142b concentrations using infrared spectroscopic techniques.     

Effects of vertical grid discretization in infrared transmission modeling

The vertical spacing of a discretization used to model transmission in the mid-infrared spectral range was investigated. The forward model employed in this study is a part of an algorithm used to retrieve trace gas profiles from high-resolution ground-based solar absorption Fourier transform infrared (FTIR) spectra, however, the results have general applicability. A finely spaced retrieval grid was constructed and made progressively more sparse in the troposphere and in the stratosphere. The effect was quantified in terms of transmission differences with respect to the most fine discretization for a suite of molecules (H₂O, O₃, CO, CO₂, CH₄, N₂O, NO, NO₂, HCl, HF, HNO₃, ClONO₂, and N₂) in microwindows commonly used in FTIR spectroscopy. Systematic differences in modeled transmissions are apparent when coarser grid schemes are used for all species and microwindows, though some are below random noise levels typical of spectra recorded at Toronto. The most significant are H₂O and O₃ at 0.30-0.73% and 0.10-0.34%, respectively. CO (0.13%), ClONO₂ (0.84%), and HF (1.03%) are also influenced by the interference of H₂O, which is sensitive to temperature interpolation errors via the lower state energy of the particular H₂O transition. O₃ is a significant interference in CO (0.42%) and ClONO₂ (0.31%) microwindows, but its influence is felt primarily via interpolation errors in the O₃ number concentration profile introduced by the coarser grids. HCl and HF themselves show the next most significant response in transmission to coarser stratospheric grids (∼0.18%). Finally, considering transmission differences >0.1% as significant in typical measurements, we identify maximum tropospheric and stratospheric layer widths that still lead to negligible transmission errors as, respectively, 0.6 and 2.0 km. These numbers can vary depending on the band or transition of interest, the signal-to-noise ratio of the measurement and the use of significantly different a priori volume mixing ratio profiles.