Thermodynamics of Surface Defects at the Aspirin/Water Interface

We present a simulation scheme to calculate defect formation free energies at a molecular crystal/water interface based on force-field molecular dynamics (MD) simulations. To this end we adopt and modify existing approaches to calculate binding free energies of biological ligand/receptor complexes to be applicable to common surface defects, such as step edges and kink sites. We obtain statistically accurate and reliable free energy values for the aspirin/water interface, which can be applied to estimate the distribution of defects using well-established thermodynamic relations. As a show case we calculate the free energy upon dissolving molecules from kink sites at the interface. This free energy can be related to the solubility concentration and we obtain solubility values in excellent agreement with experimental results.Comment: 12 pages, 5 figure

Mentoring international postgraduate students and early career researchers through transnational telecollaboration: a supervisor’s autoethnography

The high-calibre education in Australia has attracted overseas students to pursue a Higher Degree by Research (HDR) every year. While HDR training is crucial for all HDR students, international students are relatively vulnerable due to the challenging demands of academic writing and research, coupled with the cultural and language barriers different from their own. To worsen the situation, the global pandemic forced face-to-face supervision into remote supervision mode, thus exacerbating students’ social-emotional learning state even further. This article transports readers to a telecollaborative project that I initiated amid the pandemic through an autoethnographic approach. Propelled by the urgent need to better support supervisees beyond boundaries, I enacted a transnational telecollaboration to mentor international HDR students to position themselves as emerging researchers. Informed by participatory action research (PAR), I guided my junior colleagues (early career researchers (ECRs)) to conduct HDR needs analysis, hold HDR training webinars, build a virtual community via Facebook, and shadow HDR students throughout their reflection journaling via Google Docs. This viable supervision model broke down the power structure by creating an ecologically balanced framework, thus promoting collaboration rather than isolation

The crossroads of English language learners, task-based instruction, and 3D multi-user virtual learning in Second Life

English as a foreign language (EFL) learners' task-based practices in 3D multi-user virtual environments are a dynamic avenue that has attracted research attention in current second language acquisition literature. This study explores EFL adult learners' perceptions and language practices in a 10-session, task-based course in Second Life (SL). A full-blown task-based syllabus that capitalized on meaningful real-life tasks was designed and documented in this study. Employing the grounded theory approach and triangulating multiple qualitative data sources, two core themes emerged: factors that influence SL learning experience and effects of task-based instruction on language learning in SL. SL was evidenced as a viable learning environment due to its conspicuous features, immersive and virtual reality, sense of tele- and co-presence. This study implicates that 1) 3D multimodal resources in SL provide EFL learners with visual and linguistic support and facilitate language teaching and learning; and 2) tasks that draw upon SL features, accommodate learners' cultural/world knowledge, and simulate real-life scenarios, can optimize learners' virtual learning experiences

EFL learners’ strategy use during task-based interaction in Second Life

Motivated by theoretical and pedagogical concerns that the link between second language (L2) learners’ second language acquisition (SLA) and language use in 3D multi-user virtual environments (MUVEs) is still not fully connected in current SLA literature, this study examined the patterns of English as a foreign language (EFL) learners’ employment of communication strategies during task-based interaction in Second Life (SL). Nine adult EFL learners worldwide were recruited, and they used their avatars to negotiate meaning with peers in interactional tasks via voice chat in SL. Results reveal that confirmation checks, clarification requests, and comprehension checks were the most frequently used strategies. Other types of strategy use were also discovered, such as a request for help, self-correction, and topic shift – accompanied by a metacognitive strategy and spell-out-the-word that had not been previously documented in task-based research in 3D MUVEs. This study demonstrated that SL could offer an optimal venue for EFL learners’ language acquisition to take place and prompt their cognitive processing during task-based interaction. Additionally, 3D multimodal resources afforded by SL provide additional visual support for EFL students’ input acquisition and output modifications. A call for more research on voice-based task interaction in 3D MUVEs is also needed

Managing customer relationships: Should managers really focus on the long term?

Researchers and business thought leaders have emphasized that, towards maximizing the lifetime value of customers, firms must manage customer relationships for the long term. In contrast to this recommendation, we demonstrate that firm profits in competitive environments are maximized when managers focus on the short term with respect to their customers. Intuitively, while a long term focus yields more loyal customers, it sharpens short term competition to gain and keep customers to such an extent that overall firm profits are lower than when managers focus on the short term. Further, a short term focus continues to deliver higher profits even when customer loyalty yields a higher share-of-wallet or reduced costs of service from the perspective of the firm. Intuitively, while such revenue enhancement or cost reduction effects enhance the proverbial pot of gold at the end of the rainbow, they lead to even more intense competition to gain and keep customers in the short term. These findings suggest that the competitive implications of a switch to a long term customer focus must be carefully examined before such a switch is advocated or implemented. Paradoxically, customer lifetime value may be maximized when managers focus on the short term.target pricing; customer equity; price discrimination; customer relationship marketing; customer acquisition; customer retention;

Dry Powder Microfeeding System for Solid Freeform Fabrication

Second generation SFF techniques allow both composition and shape to be downloaded directly from a computer file so that 3D functionally graded materials (FGM) can be assembled. Methods for multi-material deposition are also needed in combinatorial research, colour management and pharmaceutical dosing. In this work, computer-controlled microfeeding systems using ultrasonic vibration of a capillary were built. A wide range of stable flow rate control and switching control were achieved in the acoustic vibration system, and uniform powder doses were obtained in the ultrasonic system. The experimental results show that the nozzle diameter, transmission fluid depth, waveforms, voltage amplitude, frequency and oscillation duration all influence the dose mass. Among these factors, the nozzle diameter, voltage amplitude and oscillation duration can be used to control the dose mass. Raster printing of patterns with various resolution and dot size are demonstrated.Mechanical Engineerin