Forces acting between individual grains in a powder can have a critical and controlling effect on powder bulk behaviour. Operations such as powder flow, fluidisation, compaction, agglomeration and mixing are all influenced significantly by the intensity of interparticle forces. This is especially true when the particle size falls below around 100 mum at which point the surface forces outweigh the force due to gravity acting on a single particle. Studies of cohesion using bulk powder samples are of limited use because it is difficult to decouple the fundamental mechanisms of interparticle force from other contributions to cohesion such as variations in the powder microstructure, or geometric interlocking of individual particles. A review of the relevant literature has unearthed conflicting evidence associated with the influence of relative humidity (RH) on both bulk powder cohesion and interparticle force. Therefore there is a need for experimental force studies at the scale of the individual particle to identify the fundamental mechanisms that prevail and resolve some of the apparent uncertainty that currently exists. A custom built force instrument, incorporating Atomic Force Microscope (AFM) technology, was designed, constructed and commissioned. This instrument was used to quantify the interactions between particles of around 40 mum in diameter and flat surfaces as a function of the relative humidity of the surrounding air. Interactions between soda-lime glass surfaces, gold surfaces and amorphous quartz surfaces were studied. Striking results were obtained on soda-lime glass surfaces upon decreasing the RH from > 70% to around 40%. At this point the glass surfaces suddenly exhibited a strong repulsion upon approach. The range of this repulsion was observed at separation distances as great as 250 nm. Once the surfaces were brought into contact the strong repulsion was accompanied by a very large force of adhesion. This strong repulsion and associated peak value of adhesion was not observed at other RH values and was specific to desorption rather than adsorption. Force curves for gold and quartz surfaces showed no such repulsion and peak adhesion. It is thought that the critical humidity coincides with the formation of a complete monolayer of adsorbed water molecules. A number of possible explanations have been offered for the effect and its uniqueness to soda-lime glass in the present experiments. Theoretical calculations of adhesion force have been performed based on the concept of capillary meniscus formation. Calculations give values of around 17000 nN for a sphere 40 mum in diameter and a contact angle of 20°. These values are somewhat larger than measured values in all cases apart from peak adhesion. It is thought that at low humidities there is insufficient water adsorbed to overcome the effect of surface roughness. Contact occurs at asperities, which reduces the expected contact area and hence leads to an adhesive force that is lower than predicted. At humidities > 80% the experiments show evidence of capillary elongation upon surface separation. This implies that the surface adsorbed film is mobile with bulk liquid being drawn into the bridge under the action of the surface tension force. The associated increase in bridge volume and the change in bridge curvature with I elongation will tend to equalise the Laplace pressure inside the bridge and therefore give a value of adhesion that is lower than predicted.

No description available.

No description available.

The United Nations Convention on the Rights of the Child (UNCRC) calls for education to prepare children for "responsible life in a free society, in the spirit of understanding, peace, tolerance, equality of sexes, and friendship among all peoples, ethnic, national and religious groups and persons of indigenous origin" (UN, 1989, p.9). This thesis examines the potential role of Educational Psychologists (EPs) in addressing the UNCRC call to promote community cohesion through their work in schools. A systematic review of recent international research into the effects of psychology-based educational approaches promoting community cohesion was undertaken. The review, structured by the PRISMA framework, identified 13 studies examining the effects of approaches to community cohesion. Analysis of these studies yielded insight into approaches to community cohesion, which may be best promoted through educational approaches that have both knowledge and process-based components and through a multi-level approach, which takes into account the individual and their relationships as well as the relationships between community groups and the individual's participation in their community. An empirical study with an Educational Psychology Service (EPS) in the North West of England was undertaken. This consisted of an Appreciative Inquiry cycle of four focus groups exploring ways in which an EPS could envisage promoting community cohesion. Findings from the empirical study suggest that an EPS supporting community cohesion is facilitated by aspects of current EP practice including values and by EPs knowing their school communities. EPs reflecting on their own positionality regarding community and culture may also be a facilitator. Dissemination to EP practice was considered, both at the research site as well as within the profession more generally. A multi-level approach was generated in which dissemination to practice through journal publication, conference presentations and continued contribution to a working group of regional EPSs was planned alongside dissemination through the design and delivery of training packages for schools. Deliberation over whether adopting a children's rights-based approach could help to maintain focus on community cohesion through times of changing government priorities was discussed.

One of the aims of this study is to identify shifts of cohesion in translation from Spanish into English, with a view to validating Blum-Kulka's proposal that explication is a universal strategy in translation. The study uses the translation work of ten advanced translation students using narrative texts of approximately 250 words in length. Some of these students are native speakers of Spanish and others native speakers of English. Another aim of the study is to examine how cohesive devices are deployed across an ability range of students and to establish whether there are systematic differences in their deployment. The study will also attempt to establish whether the levels of language competence of informants account for specific shifts of cohesion in translation and whether certain shifts of cohesion are motivated by the style of the source and target texts. / Master of Arts (Hons)

Master of Public Health / Department of Kinesiology / Brandon Irwin / Purpose: Face-to-face group dynamics-based (GDB) programs have been shown to be effective in promoting group cohesion and physical activity (PA). Recent evidence suggests that GDB principles can be successfully translated to web-based applications to impact group cohesion. The social nature of such applications allows for interactions to occur between friends and strangers alike, potentially moderating the effects of such GDB applications. Optimal group composition within GDB web applications has yet to be determined. The present study examines the moderating effects of group composition in a GDB application on group cohesion and PA. Methods: Participants (n = 166) were randomized into same-sex pairs and then randomly assigned to an experimental condition: stranger (no app), stranger (using app), friend (using app) or individual control. Participants in all conditions performed two sets of planking exercises. In between sets, those in partnered conditions interacted with their partner using a GDB social media app, where they participated in a series of team-building activities. The main dependent variables were group cohesion and physical activity, calculated as the total persistence during Block 2, controlling for Block 1 persistence. Results: Results indicate that the group integration dimensions of cohesion were higher in groups that used the application than those that did not (GI-T: p= .001; GI-S: p= .004). Friends that used the app reported greater cohesion across all dimensions than strangers that did the same (ATG-T: p= .006; ATG-S: p= .003; GI-T: p= .001; GI-S: p< .001). There was also a significant difference in PA (p=.004) between the two app-using conditions. However, there was no significant difference in PA between app using conditions and strangers that did not use the app (p= .495). Conclusions: Group cohesion can be enhanced through the use of an online GDB application. Using an online GDB application with a friend is associated with higher levels of cohesion. Further research is necessary to identify effective online GDB applications for impacting physical activity and cohesion in field settings.

No description available.

Thesis (M.S.)--Southern Utah University, 2009. / Title from PDF title page. "July 2009." "In partial fulfillment of the requirement for the degree [of] Master of Arts in Professional Communication." "A thesis presented to the faculty of the Communication Department at Southern Utah University." Dr. Suzanne Larson, Thesis Supervisor Includes bibliographical references (p. 30-34).

Thesis (Ph.D)--Materials Science and Engineering, Georgia Institute of Technology, 2008. / Committee Co-Chair: Dr. Hamid Garmestani; Committee Co-Chair: Dr. Rina Tannenbaum; Committee Member: Dr. Kenneth Gall; Committee Member: Dr. Meisha Shofner; Committee Member: Dr. Thomas Sanders. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Proefschrift--Leyden. / "Samenvatting": p.[164]-169. Includes bibliographical references.