The Effect of Changes in Environmental Conditions on the Mechanical Behaviour of Selected Paint Systems

ABSTRACT

The impact of relative humidity (RH) and temperature variation on the mechanical behaviour of paintings on canvas was investigated, based on the various environmental recommendations that are applied by museums and institutions worldwide. Paint samples were constructed based on the works of twentieth-century artists such as Soulages and Riopelle. The various samples are based on criteria such as paint media, additives, pigment type, canvas type, thickness, type of application, and drying time. Once they are fully dry, paint films behave as elastic, viscoelastic, or viscoplastic materials depending on the chemical nature of their components. These properties, as well as tensile strength, were determined by a series of tensile tests. Other samples were included, originating from discarded oil paintings on canvas from the seventeenth and nineteenth centuries. To carry out mechanical tests under controlled conditions of temperature and RH, a climatic chamber was built around the column of a universal testing machine. Samples were submitted to stress relaxation tests to observe their response to changes in environmental conditions. RH was increased from 20 to 90% and temperature from 15 to 60°C. Reactivity diagrams were drawn based on the results. The endurance limit under mechanical fatigue was determined from the diagrams and helped define the risks associated with each painting type when exposed to the accepted environmental recommendations.     

Educational inclusion in Singapore for children with physical disabilities

Under Singapore’s inclusive education policy, children with mild physical disabilities are integrated into mainstream schools. There is currently no known published research yet in Singapore on the outcomes of inclusion for children with physical disabilities. Internationally, recent research had compared the school experience of children with physical disabilities to that of their typically developing peers. This study examined the social and academic impact of educational inclusion for children with physical disabilities. It investigated how their participation in school activities, academic performance, self-esteem, peer relationships, and social/emotional development compared to that of typically developing schoolmates. A total of 60 clients (n = 30 with physical disability; n = 30 typically developing students; age range = 8 to 16 years) in a local primary and secondary regular school participated in the study. The children with physical disabilities met academic expectations in school and had comparable levels of self-esteem, but experienced peer problems and participated less in school activities. Understanding children’s overall school experience is critical to becoming an inclusive society that enables children with a range of disabilities to benefit academically and socially. Implications for practice and future research were discussed.     

Internationalising a learning environment instrument for evaluating transnational online university courses

This article describes the adaptation and validation of the Constructivist OnLine Learning Environment Survey (COLLES) for use in the transnational higher education context. As higher education becomes a more global phenomenon, ‘borderless’ education, either online or by distance education, is becoming a reality and there is a need for remote evaluation of course delivery and student learning. Curtin University of Technology is managing supported online delivery of Business Studies Degree and Diploma courses to four partner institutions of the African Virtual University, an initiative based in Nairobi, Kenya. Evaluation of students’ learning has included an online survey about the provision of resources and the quality of the learning environment in the various computer-based classrooms. Embedded in this instrument has been the adapted COLLES, providing a concomitant opportunity to test the properties and usefulness of the learning environment instrument. Problematic issues surrounding adaptation of the instrument have included the consequences of modifying the wording and establishing or confirming the meaning of the latent constructs in partially online courses and for transnational students. The process of establishing the validity and reliability of the scales is discussed.     

A Pilot Study Applying Social Cognitive Theory to Predict HPV Vaccination Intentions of Unvaccinated College Women

Although college-aged women are at high risk for human papillomavirus (HPV) infection, many college women remain unvaccinated against HPV. Testing health behavior theory can assist sexuality educators in identifying behavioral antecedents to promote behavior change within an intervention. The purpose of this pilot study was to utilize social cognitive theory (SCT) to predict unvaccinated college women's intentions to receive the HPV vaccine within the next six months. A total of 197 unvaccinated college women ages 18–26 attending a large public southeastern university in the United States completed an online questionnaire to assess SCT constructs. Expectations, HPV knowledge, self-efficacy to get the HPV vaccine, situational perception, self-control to get the HPV vaccine, and self-efficacy in overcoming barriers to get the HPV vaccine were regressed on HPV vaccination intentions using the stepwise method. Self-control (p < 0.001, β = .292) and situational perception (p < 0.001, β = .332) were significant predictors of intentions to receive the HPV vaccine, explaining 23.5% of its variance. The results of this pilot study suggest that sexuality educators should aim to increase self-control and situational perception in order to increase HPV vaccination intentions among college women.     

Using the value creation framework to capture knowledge co-creation and pathways to impact in a transnational community of practice in autism education

ABSTRACT

Although theories around Communities of Practice have gained significant ground in recent years and have become an important focus for organizational development, there is a gap in studies that investigate what members gain from participation in these communities. This paper explains how the value creation framework was implemented in a transnational research and development project in autism education by examining cycles of value creation and drawing on two types of data identified by Wenger and colleagues. The value creation framework is a theoretically driven framework to assess social learning in communities. Participants involved in the learning space were co-researchers engaged in a process of investigating, sharing and reflecting on their practice. The paper discusses the methodological challenges and strengths of using the value creation framework, with a particular focus on how insights and interactions led to subsequent changes in the practice of the participants. This work has the potential to make an important contribution to methods and analysis in assessing social learning and pathways to impact in participatory research and development projects more broadly.     

Exploring the Meanings of Hijab through Online Comments in Canada

Controversies surrounding ethnic dress such as hijab have increased public awareness about cultural diversity. The number of comments posted on online media make it evident that many people are concerned about ethnic attire, cultural differences and social cohesion. Although researchers have examined the meanings of veiling, the relationships between hijab and public opinion have seldom been investigated. The overarching objective of this study was to understand the relationships between Islamic attire and online readers’ opinion. In light of the limitations in the previous studies on this topic, this study attempts to fill the gap by studying posters’ opinions toward hijab through publicly available online information in the form of posted comments.     

Preface to Special Topic: Papers from the 13th International Conference on Surface and Colloid Science (ICSCS) and the 83rd ACS Colloid and Surface Science Symposium, Columbia University, New York, 2009

This Special Topic section is a compilation of several original contributions covering both fundamental and practical aspects of electrokinetic microfluidic phenomena that were presented during the Electrokinetics and Microfluidics sessions held at the conference.Electrokinetics is currently the mechanism of choice for the manipulation of fluids as well as colloidal and biological particles at microscale and nanoscale dimensions.¹ The popularity of electrokinetics is perhaps not so surprising as electrodes are easy to fabricate and embed into microfluidic chips, thus allowing the entire fluid and particle actuation mechanism to be completely integrated into the device. In addition, driving microfluidics with electric fields is relatively straightforward and allows for precise actuation. Nevertheless, considerable challenges remain in understanding the complex mechanisms associated with the hydrodynamics of conducting and dielectric fluids and particles under the influence of electric fields. Concomitantly, there has been an exponential increase in research and development in this field along both fundamental and applied themes in the past five years.This sustained growth in the microfluidics community of electrokinetics research has led to a sequel to the first Electrokinetic Phenomena and Microfluidics session at the 82nd ACS Colloid and Surface Science Symposium in Raleigh, NC, in 2008, and which we hope will now be a regular feature at successive ACS Colloid and Surface Science meetings. This year at the combined 2009 13th International Conference on Surface and Colloid Science (ICSCS) and the 83rd ACS Colloid and Surface Science Symposium in New York, the Electrokinetics and Microfluidics symposium proved to be extremely popular, with three keynote lectures presented by Professor Howard Stone, Professor Hsueh-Chia Chang, and Professor Thomas Healy, and 44 oral presentations. In both 2008 and 2009, Biomicrofluidics has organized a special issue to cover some of the contributions reported at these meetings.²The growing interest in using electric fields to manipulate biological entities such as cells, DNA, and even single molecules is reflected in this year’s collection of papers with dielectrophoretic (DEP) phenomena comprising the bulk of the contributions. In Ref. ³, a new theory to describe Stern layer conductance along the surface of nanocolloids is proposed, forming the basis for the derivation of a more accurate prediction of the DEP crossover frequency. This theory is then employed to determine the conformation and, hence, optimum coverage of oligonucleotides on the surface of nanocolloid functionalized molecular probes during DNA hybridization under the influence of DEP, which can be exploited for biomolecular sensing. Other fundamental DEP papers include the investigation of particle motion under DEP induced optically via a photoconductor, in which Zhu et al.⁴ characterized the frequency dependence of the motion through the synchronous velocity spectra of the particles, and a numerical study of particle trapping at the throat of converging-diverging microchannels under the influence of negative DEP using a transient arbitrary Lagrangian–Eulerian finite element method.⁵ A more practical implementation is, on the other hand, reported by Yang et al.⁶ in which the negative DEP is exploited to separate colorectal cancer cells from other cells in a microfluidic device as a demonstration of a portable cancer detection tool.Continuing along the separation theme, but with regard to DNA separation using pulsed-field gel electrophoresis aided by sparse but regularly ordered microfabricated arrays of nanoposts, is a Brownian dynamics simulation model reported by Ou et al.⁷ in which DNA channeling, which predicts that the motion of DNA is undisturbed by the presence of arrays for large spacing to DNA equilibrium size ratios and when the field lines are straight, is predicted, consistent with experimental observations. In another fundamental paper, a direct numerical simulation model is presented to predict the current-voltage relationship across conducting pores along cell membranes, which is of fundamental importance in the electroporation process.⁸We hope that you will enjoy reading the contributions in this special topic and that it encourages you to participate in future Electrokinetics and Microfluidics meetings at the ACS Colloid and Surface Science Symposia, which we definitely hope will continue on a regular basis.