Statistical evaluation of the damage potential of earthquake ground motions

This study focuses on the damage potential of earthquake ground motions based on the inelastic dynamic response of equivalent single degree of freedom structures. Their yield resistances are selected in accordance with seismic design codes. An index accounting for the accumulation of damage due to inelastic excursions is used to represent structural damage. A set of 94 ground motions are employed for this analysis, which are all scaled to the same peak ground acceleration of 0.4 g. Earthquake ground motions are classified with respect to both the ratio of peak velocity to peak acceleration (V/A ratio) and their effective excitation duration. The effect of these parameters on damage potential is investigated by using sensitivity analysis and probabilistic techniques. It is concluded that both V/A ratio and effective duration significantly influence the damage potential of earthquake ground motions, although they are not represented appropriately by the spectral definitions of earthquake excitations in seismic design codes.     

EFFECT OF FINE SOLID PARTICLES ON GAS-LIQUID MASS TRANSFER RATE IN A SLURRY REACTOR

The influence of suspended fine particles of differing adsorbing capacity (activated carbon, avicell cellulose, SiO₂, and molecular sieves) on the liquid-film mass transfer coefficient κ_L, was examined experimentally in a stirred cell of well-defined gas-liquid interfacial area by chemical methods. The greatest effect on κ_L was observed with the activated carbon (about a threefold increase). An addition of glycerine in excess of 2.5 × 10^-3 k mol/m³, which was adsorbed on the particles preferentially, removed this increase in κ_L totally. Amongst other particles, only avicell cellulose showed measureable effects. The increase in κ_L values was inversely proportional to the temperature and the stirring speed, and the particle loading was found to be immaterial after a certain value. When the reaction rate increased (hence, when the thickness of dissolved gas-rich layer decreased) by gradual addition of a homogeneous catalyst (i.e. Co⁺⁺ for sulphite oxidation), the effect of particles on κ_L decreased and eventually it disappeared.     

Modeling of batch catalytic chlorination of toluene in a bubble column

The chlorination of toluene was studied in a batch bubble column in the presence of ferric chloride. Mass transfer studies (in the absence of dissolved catalyst) showed that Cl₂ absorption into toluene was controlled up to 60% by the gas side mass transfer resistance. In addition, the experimentall obtained liquid side mass transfer coefficients were found to be very low, i.e. more than 10 times lower than the predictions from common correlations. A model was developed which describes the batch chlorination process with striking agreement on the basis of the mass transfer data measured in this study and the solubility and kinetic data reported recently. It was found that the first chlorination step took place in the transition from diffusiona to fast reaction regime. However, due to the dominating gas side resistance, the overall process was only slightly enhanced by the reaction in the liqu     

Success rates with gamete intrafallopian transfer and in vitro fertilization in women of advanced maternal age

OBJECTIVE: To evaluate the effect of maternal age on outcomes for IVF and GIFT in women 40 to 45 years of age. DESIGN: Retrospective. SETTING: Boston IVF, a free-standing university-affiliated IVF and GIFT unit. PATIENTS: A total of 2,931 cycles of IVF and 1,826 cycles of GIFT were analyzed in women undergoing assisted reproductive technologies (IVF or GIFT) using autologous eggs. INTERVENTIONS: Medical records of patient outcomes were reviewed. RESULTS: For patients undergoing IVF, the cancellation rate for initiated cycles showed significant differences in women aged 25 to 39 (38.3%), women aged 40 to 43 (49.5%), and women aged 44 to 45 years (69.5%). A significantly lower delivery rate per stimulation and delivery rate per retrieval was found in women aged 40 to 43 years when compared with women aged 25 to 39 years. No deliveries occurred in 59 cycles in women aged 44 to 45 years, thereby representing a significant difference when compared with both women aged 25 to 39 years and women aged 40 to 43 years. For patients undergoing GIFT, the cancellation rate for initiated cycles was significantly higher in women aged 40 to 43 (25.0%) and 44 to 45 years (31.0%) when compared with women aged 25 to 39 years (15.1%). A significantly lower delivery rate per stimulation and delivery rate per retrieval was found in women aged 40 to 43 and 44 to 45 years when compared with women aged 25 to 39 years. CONCLUSIONS: Success rates for IVF and GIFT decline significantly in women > 40 years old. Women aged > or = 44 years are unlikely to benefit from the use of IVF and GIFT.     

Periclase solid solutions containing Li+1 and R+3 ions

Recent work on phase equilibria diagrams has shown that periclase can take R⁺³ (Cr⁺³, Al⁺³, and Fe⁺³) in solid solution at elevated temperatures. In order to retain electrical neutrality, 2R⁺³ and a vacancy replaces 3Mg⁺² in the periclase lattices. When Li⁺¹ is added to MgO/R₂O₃ compositions, one Li⁺¹ and one R⁺³ replaces 2 Mg⁺² to form a solid solution which is stable at room temperature. These periclase solid solutions are more stable under conditions of temperature fluctuations and hydration than periclase/R₂O₃ solid solutions without lithia.     

On the pictorial properties of visual images: Effects of image size on memory for words.

In 4 experiments 82 university students formed mental images of pairs of named objects touching and interacting in some way. On half of the trials, one member of the pair was imaged such that it was at a small subjective size; on the remaining half of the trials, both objects were imaged at normal relative sizes. Ss rated their images in terms of vividness. Results of an unexpected memory test presented after all the items had been rated reveal poorer recall of words encoded as smaller images. This result was not due to differences in imaginal relations between the imaged objects in the 2 conditions, nor was it due to greater ease in constructing images including a reduced member. In addition, pairs including a subjectively tiny image were rated as less vivid than pairs including images only of normally sized objects. A regression analysis indicated that the memory deficit was due to size per se and was not a consequence of differences in vividness induced by the size manipulation. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)