Multilayer film preparation of poly(4-vinylphenol) from aqueous media

The use of weak polyelectrolytes in multilayer polymer systems provides a means of altering the physico-chemical properties of these thin films. This paper examines the limits of the polyanions by incorporating the extremely weak polyelectrolyte, poly(4-vinylphenol) (PVPh), into a multilayer system with poly(allylamine hydrochloride) (PAH) from a dilute aqueous media. Film growth was monitored using absorption spectroscopy and revealed a clear linear trend in film thickness. The surface morphology, thickness, and swelling of the multilayer films systems were examined using atomic force microscopy (AFM). Film thickness greatly depended upon the pH of the polymer precursor solutions; 50-layer systems created at pH 12.5 and 11.0 were 8.2 and 246.6 nm thick, respectively, a difference of over 2900%. This is the first report on the incorporation of PVPh into a multilayer system from an aqueous media.     

Conflict in families of adolescents: The impact on cohesion and power structures.

Investigated 3 characteristics (locus, content, and frequency) of conflict (CF) in families of adolescents. Ss were 134 parents and 170 early (mean age 11.5 yrs), 109 middle (mean age 16.3 yrs), and 47 late (mean age 18.7 yrs) adolescents. Ss reported family CF on T. M. Gehring and S. S. Feldman's (see record 1989-14119-001) Family System Test and in an interview. CF in marital (MADs) and parent–adolescent dyads (PADs) was frequently reported. Across adolescence, reports of PAD CF increased, especially those related to autonomy. CF decreased cohesion and changed power relations in the representations of family structure. CF in the MAD was related to decreased cohesion and increased cross-generational coalitions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An adaptive approach to family intervention: Linking engagement in family-centered intervention to reductions in adolescent problem behavior.

This study used Complier Average Causal Effect analysis (CACE; see G. Imbens & D. Rubin, 1997) to examine the impact of an adaptive approach to family intervention in the public schools on rates of substance use and antisocial behavior among students ages 11-17. Students were randomly assigned to a family-centered intervention (N = 998) in 6th grade and offered a multilevel intervention that included (a) a universal classroom-based intervention, (b) the Family Check-Up (selected; T. J. Dishion & K. Kavanagh, 2003), and (c) family management treatment (indicated). All services were voluntary, and approximately 25% of the families engaged in the selected and indicated levels. Participation in the Family Check-Up was predicted by 6th-grade teacher ratings of risk, youth reports of family conflict, and the absence of biological fathers from the youths' primary home. Relative to randomized matched controls, adolescents whose parents engaged in the Family Check-Up exhibited less growth in alcohol, tobacco, and marijuana use and problem behavior during ages 11 through 17, along with decreased risk for substance use diagnoses and police records of arrests by age 18. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Coworker exchange: Relationships between coworkers, leader-member exchange, and work attitudes.

The study of leadership exchanges is extended by studying both leader-member exchanges (LMXs) and, coworker exchanges (CWXs). Data from 110 coworker dyads were used to examine relationships between LMXs and CWXs and between exchange relationships and work attitudes. As predicted, the interaction between 2 coworkers' LMX scores predicted CWX quality for the coworker dyad. Also, after controlling for LMX, greater diversity in a worker's CWX relationships was negatively related to his or her organizational commitment but not job satisfaction. The quality of a worker's CWX relationships, however, did not moderate the relationship between CWX diversity and work attitudes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensors and Machine Learning Models to Prevent Cooktop Ignition and Ignore Normal Cooking

Fire Technology - Cooking equipment is involved in nearly half of home fires in the United States, with cooktop fires the leading cause of deaths and injuries in cooking-related fires. In this...     

Determination of the Impact of Glycolate on Cs,Sr, and Actinide Separations in High-Level Waste

The Defense Waste Processing Facility (DWPF), responsible for vitrifying high-level waste (HLW) at the Savannah River Site (SRS), is planning to introduce glycolic acid as a reductant during chemical conditioning of the waste prior to vitrification. A portion of this glycolic acid may be recycled back to the tank farm as sodium glycolate. Since glycolate can serve as a complexing agent for a variety of metallic ions, recent studies were performed to examine the effect of glycolate on the removal of Sr and actinides by monosodium titanate (MST) and modified MST (mMST) and the separation of Cs by the caustic-side solvent extraction (CSSX) process.     

Telling tales: using stories to remake energy policy

To benefit and protect the populace, government policies often promise aspirational changes to current practice. Different kinds of narratives are important in the framing, explanation, motivation, and understanding of policies and strategies. For example, the UK government's 2008 Climate Change Act proclaimed that all new homes will be zero carbon by 2016. This ‘hero story’, where society is ‘saved’ by clever technologies, is inspiring, positive and familiar. An alternative is the ‘learning story’, where things are not quite as simple as they first seemed. In a learning story, protagonists are normal people who need to overcome a challenge. In energy policy, the learning story could address the gap between the technical potential and what is achieved in practice. Three real-world examples from retrofit and new-build projects are used to show how implicit narratives can create conflict when the tellers (e.g. researchers) have to tell one kind of story but have data for the other. Recommendations are provided for a balanced approach to the deployment of different kinds of tales by policy-makers, researchers, implementers and users. Harnessing the learning story and developing a ‘caring story’ could motivate policy-makers and the public to invest effort in building performance.     

Characterization of water distribution in xanthan-curdlan hydrogel complex using magnetic resonance imaging, nuclear magnetic resonance relaxometry, rheology, and scanning electron microscopy

Abstract: Xanthan‐curdlan hydrogel complex (XCHC) has been shown capable of retaining moisture up to 5 freeze‐thaw cycles (FTCs); however, moisture distribution in the complex in relation to the hydrogel composition and structure remains uncharacterized. In the present study, magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR) relaxometry, rheology, and scanning electron microscopy (SEM) were used to examine the effect of water distribution and interaction with 2.0% aqueous solutions of xanthan, curdlan, and XCHC consisting of equal amounts of both polysaccharides. A gel structure with an indication of syneresis was clearly seen in the MR image of curdlan alone, whereas the distribution of protons throughout xanthan and XCHC samples remained homogeneous and showed no detectable syneresis. The three‐dimensional network, indicated by frequency sweeps, of curdlan was responsible for curdlan's gel structure. The frequency sweep and slope of the storage modulus (G′) of XCHC was significantly closer to curdlan with higher elasticity and less dependency upon angular frequency than xanthan alone. The reduction in XCHC dynamic moduli (G′ and G″) compared to curdlan could be attributed to the formation of wavy layers instead of a fully cured three‐dimensional structure. Addition of xanthan to curdlan restricted XCHC spin–spin relaxation time (T₂) to intermediate and slower exchange regimes, namely approximately 110 and 342 ms, respectively, promoting the polymer's interaction with water while inhibiting interpolymer interactions found in curdlan. A 3rd proton pool with the slowest T₂ seen in curdlan was not found in XCHC, correlating to the absence of syneresis. Practical Application: The combination of texture measurements and discrete noninvasive techniques was found capable of providing insightful understanding of water distribution in a gel system. These techniques may be applied to other hydrogel complexes. The XCHC system investigated has the potential to enhance freeze‐thaw stability in frozen food products by minimizing syneresis due to undesirable temperature fluctuations during distribution and consumer application.     

Parent–child attachment and monitoring in middle childhood.

Research on parent–child attachment and parental child rearing practices has been pursued independently. The purpose of the present study was to test whether a secure attachment relationship is related to parental monitoring and child efforts to contribute to the monitoring process. This question was examined in a cross-sectional study of third- and sixth-grade children and their parents. Attachment-based measures were used to tap child and parent perceptions of attachment. Monitoring (i.e., parents' awareness of children's whereabouts and activities) was assessed through phone interviews with children and parents. Child contributions to monitoring were assessed with parent and child questionnaires. A more secure attachment was related to closer monitoring and greater cooperation by the child in monitoring situations, especially at sixth grade. The findings illustrate the importance of embedding attachment within a larger child rearing context. (PsycINFO Database Record (c) 2010 APA, all rights reserved)