The atmospheric chemical behaviour of 1,1,1,2-tetrafluoroethane (CF,CFH,, HFC-134a) with respect to its rate and mechanism of degradation in the troposphere has been investigated. The rate coefficient for the reaction of (1 a) CF3CFH2 + OH+CF3CFH + H,O has been determined in direct time-resolved experiments using laser-pulse initiation and laser long-path absorption. A value of k l a = (4.6+0.5)x lo-'' cm3/s at T = 295 K has been found. The ratio of the rate coefficients for the reactions of the CF3CFHO-radical with O,, (4) CF3CFHO+02-tCF3CFO+H02, and C-C bond fission, ( 5 ) CF,CFHO+M-+CFHO+CF, +M, for T = 295 K and ptotai = 50 mbar (0,) has been obtained to be k4/(k, [MI) = 1.5 x lo-'' cm3, with the individual values being k, = 2 . 7~ lo-'' cm3/s and k, [MI = 1 . 8~ lo4 s-'. The mechanism of the atmospheric degradation of HFC-134a has been investigated in the temperature range 244-295 K and ptotal = lo00 mbar using UV photolysis/FTIR product studies. From these experiments the Arrhenius expression k,/(k, [MI) = 8.7x exp ((32401% K/T) cm3 was determined. Moreover, it is concluded that the major carbonyl products are CF3CF0, CFHO and CF20 which result from the two possible reactions of the oxy radical CF,CFHO. As a consequence the yield of these carbonyl products is dependent on temperature, 0, partial pressure and total pressure. For the reaction of CFHO with C1 atoms the Arrhenius expression k18 = 5 . 7~ 10-14exp (-(1130 k 160) K / T ) cm3/s was determined in the temperature range 244-298 K.

A thorough investigation of triethylene glycol (TEG) containing systems has been performed. The introduction of a new six-site association scheme for the TEG molecule has shown to be advantageous. Glycols are often modeled using a four-site scheme (abbreviated as 4C) hence ignoring the internal lone pairs of oxygen. The new association scheme also takes these sites into account. The new parameters of TEG are based on the vapor pressure data, liquid density data, and liquid−liquid equilibria (LLE) data (n-heptane), and they are tested for binary systems (methane, n-octane, n-nonane, n-decane, benzene, toluene, ethylbenzene, and water) and different types of phase equilibria (vapor−liquid equilibria (VLE) and LLE) and thermodynamic properties (heat of mixing, activity coefficients). A less extensive investigation has also been performed on tetraethylene glycol (TeEG) containing systems. Similarly, a new seven-site association scheme for the TeEG molecule has been investigated. The new parameters of TeEG are based on vapor pressure data, liquid density data, and LLE data (n-heptane). The performance is similar to that the 4C scheme.

The cubic-plus-association (CPA) equation of state is applied in this work to mixtures containing acetic acid and water. A previously developed modification of the model, the so-called CPA-Huron−Vidal (CPA-HV), is used. New CPA parameters have been estimated based on the vapor pressure, liquid density, enthalpy of vaporization, and vapor-phase compressibility factor data. The CPA-HV parameters have been fitted to, among others, experimental vapor compressibility factor data and experimental relative volatility data at different temperature ranges. The purpose of the work was to investigate whether the CPA-HV model can describe the vapor−liquid equilibrium for acetic acid−water over a temperature range of 200 K and at the same time represent the behavior of pure acetic acid and acetic acid−water mixtures with respect to enthalpies of vaporization and compressibility factors. It is shown that satisfactory results are overall obtained, but if an excellent match is needed over the whole temperature range, then different interaction parameters need to be used at the various temperature ranges.

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IntroductionSudden cardiac arrest is one of the most frequent causes of death in the world. In highly qualified emergency medical service (EMS) systems, including well-trained emergency physicians, spontaneous circulation may be restored in up to 53% of patients at least until admission to hospital. Compared with these highly qualified EMS systems, markedly lower success rates are observed in other systems. These data clearly show that there are considerable differences between EMS systems concerning treatment success following cardiac arrest and resuscitation, although in all systems international guidelines for resuscitation are used. In this study, we investigated the impact of response time reliability (RTR) on cardiopulmonary resuscitation (CPR) incidence and resuscitation success by using the return of spontaneous circulation (ROSC) after cardiac arrest (RACA) scores and data from seven German EMS systems participating in the German Resuscitation Registry.MethodsAnonymised patient data after out-of-hospital cardiac arrest gathered from seven EMS systems in Germany from 2006 to 2009 were analysed with regard to socioeconomic factors (population, area and EMS unit-hours), process quality (RTR, CPR incidence, special CPR measures and prehospital cooling), patient factors (age, gender, cause of cardiac arrest and bystander CPR). End points were defined as ROSC, admission to hospital, 24-hour survival and hospital discharge rate. χ2 tests, odds ratios and the Bonferroni correction were used for statistical analyses.ResultsOur present study comprised 2,330 prehospital CPR patients at seven centres. The incidence of sudden cardiac arrest ranged from 36.0 to 65.1/100,000 inhabitants/year. We identified two EMS systems (RTR < 70%) that reached patients within 8 minutes of the call to the dispatch centre 62.0% and 65.6% of the time, respectively. The other five EMS systems (RTR > 70%) reached patients within 8 minutes of the call to the dispatch centre 70.4% up to 95.5% of the time. EMS systems arriving relatively later at the patients side (RTR < 70%) initiate CPR less frequently and admit fewer patients alive to hospital (calculated per 100,000 inhabitants/year) (CPR incidence (1/100,000 inhabitants/year) RTR > 70% = 57.2 vs RTR < 70% = 36.1, OR = 1.586 (99% CI = 1.383 to 1.819); P < 0.01) (admitted to hospital with ROSC (1/100,000 inhabitants/year) RTR > 70% = 24.4 vs RTR < 70% = 15.6, OR = 1.57 (99% CI = 1.274 to 1.935); P < 0.01). Using ROSC rate and the multivariate RACA score to predict outcomes, we found that the two groups did not differ, but ROSC rates were higher than predicted in both groups (ROSC RTR > 70% = 46.6% vs RTR < 70% = 47.3%, OR = 0.971 (95% CI = 0.787 to 1.196); P = n.s.) (ROSC RACA RTR > 70% = 42.4% vs RTR < 70% = 39.5%, OR = 1.127 (95% CI = 0.911 to 1.395); P = n.s.)ConclusionThis study demonstrates that, on the level of EMS systems, faster ones more often initiate CPR and increase the number of patients admitted to hospital alive. Furthermore, we show that, with very different approaches, a...