Synthesis of polar vinyl monomer–olefin copolymers by α‐diimine nickel catalyst

Vinyl acetate, methyl methacrylate, acrylonitrile and methyl vinyl ketone were investigated for co‐ and terpolymerization with ethylene and ethylene–propylene. Precursor [bis(N,N ′‐dimesitylimino)acenaphthene]dibromonickel, activated by methylaluminoxane was used as a catalyst system and trialkylaluminium was employed to block the polar groups for these polymerizations. Polymerization activities of the order of magnitude of 10⁶ in the case of vinyl acetate and methyl methacrylate, and 10⁵ in the case of acrylonitrile were achieved. Microanalysis and GPC of acrylonitrile copolymers found about 17 units of acrylonitrile per polymer chain. Copolymers with very different properties from the parent homopolymers were obtained in all cases except that of methyl vinyl ketone. © 2001 Society of Chemical Industry     

Thermodynamic and nonstoichiometric behavior of promising Hi-Tc cuprate systems via electromotive force measurements: A short review

Electromotive force (EMF) measurements of oxygen fugacities as a function of stoichiometry have been made on the YBa₂Cu₃O _x , GdBa₂Cu₃O _x , NdBa₂Cu₃O _x , and bismuth cuprate systems in the temperature range ∼400 °C to 750 °C by means of an oxygen titration technique with an yttriastabilized zirconia electrolyte. The shapes of the 400 °C isotherms as a function of oxygen stoichiometry for the Gd and Nd cuprate systems suggest the presence of miscibility gaps at values of x that are higher than those in the YBa₂Cu₃O _x system. For a given oxygen stoichiometry, oxygen partial pressures above GdBa₂Cu₃O_x and NdBa₂Cu₃O _x the higher (above x=6.5) than that for the promising YBa₂-Cu₃O_x system. This article is based on a presentation made at “The Milton Blander Symposium on Thermodynamic Predictions and Applications” at the TMS Annual Meeting in San Diego, California, on March 1–2, 1999, under the auspices of the TMS Extraction and Processing Division and the ASM Thermodynamics and Phase Equilibrium Committee.     

Contributions of automatic and controlled processes to the analysis of hierarchical structure.

Three experiments provide evidence that 2 mechanisms, 1 automatic and 1 controlled, produce variations in the efficiency with which local and global forms are processed. Targets are identified faster if they appear at the same level (global or local) as the target on the previous trial. M. R. Lamb, B. London, H. M. Pond, and K. A. Whitt (see record 1997-39043-003) provided evidence that the beneficial effect of level repetition is due to an automatic process that is outside voluntary control. In the present experiments, pretrial cues informed participants as to the level of the upcoming target. Valid cues benefited performance, whereas invalid cues harmed performance relative to noninformative neutral cues. This was so even when the relation between the cue and the level it signaled was arbitrary, indicating that the cues initiated voluntary shifts of attention. The benefit associated with level repetition, however, was unaffected by the cues. These data suggest that the benefit of level repetition results from a process that is not subject to voluntary control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extension of the rejection sensitivity construct to the interpersonal functioning of gay men.

On the basis of recent evidence suggesting that gay men are particularly likely to fear interpersonal rejection, the authors set out to extend the rejection sensitivity construct to the mental health concerns of gay men. After establishing a reliable and valid measure of the gay-related rejection sensitivity construct, the authors use this to test the mediating effect of internalized homophobia on the relationship between parental rejection of one's sexual orientation and sensitivity to future gay-related rejection. The present data support this mediational model and also establish rejection sensitivity's unique contribution to unassertive interpersonal behavior in the context of internalized homophobia and parental rejection. The authors conclude that gay-related rejection sensitivity is a useful construct for clinicians working with gay men given the impact that past gay-related rejection can have on their gay clients' present cognitive-affective-behavioral functioning. The authors discuss the possibility of revising rejection-prone schemas in clinical work with gay men. Future research is necessary to further examine the internal processing and interpersonal functioning of gay men by using existing constructs (or modifications of them) that are likely to be particularly relevant to the unique concerns of this population. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Some dubious premises in research and theory on racial differences: Scientific, social, and ethical issues.

The scientific premises for looking for statistical differences between groups designated as races (on somewhat arbitrary grounds) are questionable. The explanation of such differences in strictly biological-evolutionary terms is even more dubious. Studies of temperament, basic personality traits, disorders (such as antisocial personality), and specific genetic markers show that there is much more variation within groups designated as races than between such groups. Investigators and theoreticians interpreting such differences on the basis of limited sampling within the 3 broad racial groups should be careful to avoid selectivity and misrepresentation of data that serve racist ideology, and should be cautious about presenting their theories to the public through inappropriate media forums. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Even-parity finite-element transport methods in the diffusion limit

We use an asymptotic analysis to investigate the behavior of continuous finite-element-method (CFEM) discretizations of the even-parity transport equation, in problems containing optically thick diffusive regions. Our first interesting result is that we can analyze the entire family of even-parity CFEMs, and can do so in three dimensions on an arbitrarily-connected grid. (Previous asymptotic analyses have been restricted to specific discretizations, either in slab geometry or in XY geometry on a rectangular grid.) We show that every even-parity CFEM transport solution satisfies a corresponding CFEM discretization of the correct diffusion equation in the diffusion limit, which is a highly desirable property. We further show that this solution is subject to a Dirichlet boundary condition given by a cosine (|n·Ω|) weighting of the incident intensity. We show that this boundary condition, which is less accurate than we would like, means that in certain problems the transport solution in a diffusive region can be more than a factor of two greater than the correct solution. We also show that the CFEM transport solution can be incorrect in non-diffusive regions that are adjacent to diffusive regions, no matter how fine the spatial grid is in the non-diffusive region. We give numerical results from slab geometry verifying the predictions of our analysis.     

Novel measurement system for respiratory aerosols and droplets in indoor environments

The SARS-CoV-2 pandemic has created a great demand for a better understanding of the spread of viruses in indoor environments. A novel measurement system consisting of one portable aerosol-emitting mannequin (emitter) and a number of portable aerosol-absorbing mannequins (recipients) was developed that can measure the spread of aerosols and droplets that potentially contain infectious viruses. The emission of the virus from a human is simulated by using tracer particles solved in water. The recipients inhale the aerosols and droplets and quantify the level of solved tracer particles in their artificial lungs simultaneously over time. The mobile system can be arranged in a large variety of spreading scenarios in indoor environments and allows for quantification of the infection probability due to airborne virus spreading. This study shows the accuracy of the new measurement system and its ability to compare aerosol reduction measures such as regular ventilation or the use of a room air purifier.     

Estimating person-to-person variability in VOC emissions from personal care products used during showering

An increasing fraction of volatile organic compounds (VOC) emissions come from the domestic use of solvents, contained within myriad commonplace consumer products. Emission rates are often poorly characterized and depend significantly on individual behavior and specific product formulation and usage. Time-concentration profiles of volatile organic compounds (VOCs) arising from the use of a representative selection of personal care products (PCPs) during showering are generated, and person-to-person variability in emissions calculated. A panel of 18 participants used a standardized set of products, dosages, and application times during showering in a controlled indoor bathroom setting. Proton transfer mass spectrometry was used to measure the in-room VOC evolution of limonene (representing the sum of monoterpenes), benzyl alcohol, and ethanol. The release of VOCs had reproducible patterns between users, but noticeable variations in absolute peak concentrations, despite identical amounts of material being used. The amounts of VOC emitted to air for one showering activity were as follows: limonene (1.77 mg ± 42%), benzyl alcohol (1.07 mg ± 41%), and ethanol (0.33 mg ± 78%). Real-world emissions to air were between 1.3 and 11 times lower than bottom-up estimates based on dynamic headspace measurements of product emissions rates, likely a result of PCPs being washed away before VOC evaporation could occur.