The Adsorption of Pollutants by Peat,Lignite and Activated Chars

The ability of peat, lignite and activated chars made from peat and lignite to adsorb dyes and metals from wastewater and NO₂ from air was investigated. Equilibrium isotherms were determined to assess the maximum adsorption capacity of the adsorbents for the pollutants. Kinetic studies for the adsorption of dyes and metal ions onto the adsorbents were undertaken in agitated batch adsorbers. Mass transport models were tested to predict the concentration decay curves in batch adsorbers. The models tested were single resistance models based on the assumption of a single external mass transfer coefficient and two resistance models which included an internal diffusion coefficient and an external mass transfer coefficient. The surface phenomena which influence the extent and the rate of uptake have been studied. The equilibrium capacity data conform to Langmuir plots. A previously proposed model was used to evaluate the external single resistance mass transfer model and was successfully applied to predict the adsorption of metal ions in single component systems under batch conditions. It has been shown that the assumption of negligible intraparticle diffusion is valid and that external film diffusion is the rate limiting step in describing the adsorption processes at high sorbent loadings. The same type of result is not observed for the adsorption of coloured organic matter onto peat where the sorption processes cannot be successfully modelled by use of a single resistance model and a two resistance model incorporating internal diffusion is required. The surface phenomena which influence the extent and the rate of uptake of NO₂ have been studied. The type of chars produced and the activation processes affect the adsorption. As activation increases, micropore volume and surface area increase and the maximum capacity of the adsorbent increases. Surface area alone is not the only parameter which affects equilibrium uptake. © 1997 SCI.     

Once and for all

It has long been known that past-time operators add no expressive power to linear temporal logics. In this paper, we consider the extension of branching temporal logics with past-time operators. Two possible views regarding the nature of past in a branching-time model induce two different such extensions. In the first view, past is branching and each moment in time may have several possible futures and several possible pasts. In the second view, past is linear and each moment in time may have several possible futures and a unique past. Both views assume that past is finite. We discuss the practice of these extensions as specification languages, characterize their expressive power, and examine the complexity of their model-checking and satisfiability problems.     

Governance of Relocation: An Examination of Residential Relocation Processes in Housing Market Renewal Areas in England

This paper examines governance processes shaping the experiences of neighbourhood restructuring-induced residential relocation in Housing Market Renewal (HMR) areas in England. Since the 1950s and 1960s, residential relocation has been examined as a matter of social and political debate, especially in gentrification studies focusing mainly on negative residential relocation outcomes long after the process was over. This paper argues that such a focus had led researchers to ignore subtle, practical dimensions of relocation delivery and the causal relationships between these and often very diverse relocation experiences. Based on the HMR case, the study shows that residential relocation in a differentiated polity is delivered by complex networks of actors and that residential relocation outcomes are the result of cooperation or non-cooperation of network members. Key innovation rests in devising a theoretical vehicle that shows how governance has a profound impact on relocation delivery and residential relocation experiences.     

Reagents for investigating MAPK signalling in model yeast species

Here we present a set of resources (bacterial expression plasmids and antibodies) for the interrogation of proteins involved in yeast MAPK signalling. We constructed bacterial protein expression plasmids for 25 proteins involved in MAPK signalling in budding yeast. From these constructs we expressed and purified proteins and generated rabbit polyclonal antibodies against 13 proteins in the pheromone MAPK pathway. We verified the specificity of the antibodies and employed them to follow pathway proteins in cells stimulated with pheromone. We show that these reagents can be used to detect pheromone‐induced post‐translational modifications and changes in the oligomeric state of pathway proteins. In addition to recognizing their target proteins in Saccharomyces cerevisiae, these antibodies allow the detection of predicted orthologues in the distant evolutionary relatives Kluyveromyces lactis and Schizosaccharomyces pombe. These antibodies are new tools for investigating MAPK signalling in model yeast species and may be useful for studying MAPK signalling in higher eukaryotes. Copyright © 2010 John Wiley & Sons, Ltd.     

Fears of death in suicidal and nonsuicidal adolescents.

Suicidal, psychiatric, and normal adolescent girls and boys, ages 15–17 yrs, participated in a study on five types of death fears. A mixed within-between multivariate analysis of variance (5 factors?×?3 groups) yielded significant interactive effects indicating that there were different profiles of fears among the three groups: Relative to the other groups, suicidal adolescents displayed little differentiation between facets of fear, with differences in the magnitude of fear limited to the intrapersonal facets. Correlates of fear varied between groups: Fear was positively correlated with suicidality in normal Ss, negatively correlated with suicidality among suicidal ones, and unrelated to suicidality in the psychiatric group. It is suggested that fear of death is processed and experienced differently by suicidal and nonsuicidal adolescents to serve as a facilitator or inhibitor of suicidal behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A reexamination of newborns' ability to imitate facial expressions.

The ability to imitate facial expressions was examined in 26 newborns. Each subject observed a model showing tongue protrusion or a happy, sad, or suprised face. The frequencies of reproduction of a modeled act were compared with the average frequencies of the act during periods when other actions were modeled. A trials-to-criterion design was used. When infants observed the emotional facial expressions (happy, sad, surprise), they often responded by opening their mouths or showing lip pouts, but did not show imitative-like matching of these modeled expressions. However, when tongue protrusion was modeled, the infants did reproduce the modeled gesture. These data raise the question of whether the infants' responses to modeled facial expressions reflect true imitation, stimulus-evoked elicitation, or a stereotyped "facial gesture." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of task and ego achievement goals on help-seeking behaviors and attitudes.

We proposed that help-seeking perceptions and behaviors will be more adaptive under salient task goals relative to ego achievement goals. A total of 159 2nd- and 6th-grade Israeli children could request help as they worked on difficult puzzles in either a task or an ego goal condition. As predicted, children were more likely to request help and to explain help avoidance as guided by strivings for independent mastery in the task-focus condition. In contrast, more children in the ego-focus condition explained help avoidance in terms of masking incapacity. Skill level moderated help seeking only in the ego-focus condition, wherein requests for help were more frequent at intermediate than at both high and low skill levels. The results clarify the role of motivational factors in promoting or undermining academic help seeking and can help resolve theoretical controversy and inconsistent empirical findings concerning the relation between competence and help seeking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The design and performance of a new miniature mixer for specialty polymer blends and nanocomposites

A novel miniature mixer called the “Alberta Polymer Asymmetric Minimixer” (APAM) was designed, built and tested. In this study, polymer blends and nanofiber composites were compounded using a total of approximately 2 grams per sample. This mixer has a unique, asymmetric design consisting of a varying clearance between the rotor blade tips and the cup wall, enabling the material to be squeezed, stretched and kneaded in high shear and converging zones. Unlike the few other miniature mixing devices that are commercially available, the APAM has a combination of good mixing capability and complex flow modes required for dispersive flow, and requires minimal sample mass. In this work, the final morphology of non‐reactive blends created in the APAM was similar to that obtained in an internal mixer and in a twin‐screw extruder, and was much finer than that obtained in a MiniMAX? mixer. The final morphology in reactive blends was comparable for all the mixers. The dispersion of nanofibers is uniform for the nanocomposites blended in the APAM and comparable to the dispersion obtained in the internal batch mixer, whereas for the MiniMAX?, the nanofibers remained in bundles and were not wetted by the matrix polymer. Polym. Eng. Sci. 44:868–879, 2004. © 2004 Society of Plastics Engineers.