Characterizing Aqueous Foams by In-situ Viscosity Measurement in a Foam Column

Foam characterization is essential in many applications of foams, such as cleaning, food processing, cosmetics, and oil production, due to these applications diversified requirements. The standard characterization method, the foam column test, cannot provide sufficient information for in-depth studies. Hence, there have been many studies that incorporated different characterization methods into the standard test. It should be enlightening and feasible to measure the foam viscosity, which is both of practical and fundamental interest, during the foam column test, but it has never been done before. Here, we demonstrate a method to characterize aqueous foams and their aging behaviors with simultaneous measurement of foam viscosity and foam height. Using a vibration viscometer, we integrate foam column experiments with in-situ foam viscosity measurements. We studied the correlation among the foam structure, foam height, and foam viscosity during the foam decay process. We found a drastic decrease in foam viscosity in the early foam decay while the foam height remained unchanged, which is explained by coarsening. This method is much more sensitive and time-efficient than conventional foam-height-based methods by comparing the half-life. This method successfully characterizes the stability of foams made of various combinations of surfactants and gases

Global pedigree and national imperative:Hong Kong universities’ response to China’s grand strategies

Literature offers a theoretical framework exemplifying the inherent tensions between “becoming Chinese” and “remaining global” in the evolution of the international status of Hong Kong. Adopting this framework, this paper examines the global position of Hong Kong’s higher education through an investigation of universities’ participation in China’s Belt and Road Initiative and Greater Bay Area development plan. Specifically, drawing on data from interviews about universities’ engagement with the two Chinese grand strategies, the paper discusses university leaders and academics’ experience and perception of Hong Kong’s global status against a policy context that foregrounds a deeper integration with the Chinese national development. This discussion offers a theoretical dialogue that reveals different but overlapping scenarios for the future of Hong Kong’s higher education and sheds light on the link between the changing geopolitical contexts and international higher education

Understanding the Role of Knowledge Co-Production between Users and Developers in ISD Project: An Intellectual Capital Perspective

Information system development (ISD) has long been treated as that process that system developers craft an artifact to support business operation based on their special expertise. However, a significant portion of projects still have failed because the developed outcome cannot fit users’ needs. An emerging internal service concept indicates that, by treating ISD as one type of service, the requirement definition can be viewed as a co-production process in which users and developers integrate their own knowledge. By incorporating this concept into research design and taking intellectual capital perspective into account, this study proposed a model to examine the antecedents and consequences of knowledge co-production between users and developers. Data collected from 267 developers confirmed our hypotheses that knowledge co-production can benefit ISD outcomes, and common knowledge, relational capital and participative decision-making between these two parties increase the effectiveness of knowledge co-production effectively. Lastly, the implications toward academic and practitioner are also provided

Comparing Energy Efficiency of CPU, GPU and FPGA Implementations for Vision Kernels

Developing high performance embedded vision applications requires balancing run-time performance with energy constraints. Given the mix of hardware accelerators that exist for embedded computer vision (e.g. multi-core CPUs, GPUs, and FPGAs), and their associated vendor optimized vision libraries, it becomes a challenge for developers to navigate this fragmented solution space. To aid with determining which embedded platform is most suitable for their application, we conduct a comprehensive benchmark of the run-time performance and energy efficiency of a wide range of vision kernels. We discuss rationales for why a given underlying hardware architecture innately performs well or poorly based on the characteristics of a range of vision kernel categories. Specifically, our study is performed for three commonly used HW accelerators for embedded vision applications: ARM57 CPU, Jetson TX2 GPU and ZCU102 FPGA, using their vendor optimized vision libraries: OpenCV, VisionWorks and xfOpenCV. Our results show that the GPU achieves an energy/frame reduction ratio of 1.1–3.2× compared to the others for simple kernels. While for more complicated kernels and complete vision pipelines, the FPGA outperforms the others with energy/frame reduction ratios of 1.2–22.3×. It is also observed that the FPGA performs increasingly better as a vision application’s pipeline complexity grows

The role of drop shape in impact and splash

The impact and splash of liquid drops on solid substrates are ubiquitous in many important fields. However, previous studies have mainly focused on spherical drops while the non-spherical situations, such as raindrops, charged drops, oscillating drops, and drops affected by electromagnetic field, remain largely unexplored. Using ferrofluid, we realize various drop shapes and illustrate the fundamental role of shape in impact and splash. Experiments show that different drop shapes produce large variations in spreading dynamics, splash onset, and splash amount. However, underlying all these variations we discover universal mechanisms across various drop shapes: the impact dynamics is governed by the superellipse model, the splash onset is triggered by the Kelvin-Helmholtz instability, and the amount of splash is determined by the energy dissipation before liquid taking off. Our study generalizes the drop impact research beyond the spherical geometry, and reveals the potential of using drop shape to control impact and splash.Comment: 14 pages, 4 figure

Fabrication of a Large, Ordered, Three-Dimensional Nanocup Array

Metallic nanocups provide a unique method for redirecting scattered light by creating magnetic plasmon responses at optical frequencies. Despite considerable development of nanocup fabrication processes, simultaneously achieving accurate control over the placement, orientation, and geometry of nanocups has remained a significant challenge. Here we present a technique for fabricating large, periodically ordered arrays of uniformly oriented three-dimensional gold nanocups for manipulating light at subwavelength scales. Nanoimprint lithography, soft lithography, and shadow evaporation were used to fabricate nanocups onto the tips of polydimethylsiloxane nanopillars with precise control over the shapes and optical properties of asymmetric nanocups

Factors influencing completion of multi-dose vaccine schedules in adolescents: a systematic review.

BACKGROUND: Completion of multiple dose vaccine schedules is crucial to ensure a protective immune response, and maximise vaccine cost-effectiveness. While barriers and facilitators to vaccine uptake have recently been reviewed, there is no comprehensive review of factors influencing subsequent adherence or completion, which is key to achieving vaccine effectiveness. This study identifies and summarises the literature on factors affecting completion of multi-dose vaccine schedules by adolescents. METHODS: Ten online databases and four websites were searched (February 2014). Studies with analysis of factors predicting completion of multi-dose vaccines were included. Study participants within 9-19 years of age were included in the review. The defined outcome was completion of the vaccine series within 1 year among those who received the first dose. RESULTS: Overall, 6159 abstracts were screened, and 502 full texts were reviewed. Sixty one studies were eligible for this review. All except two were set in high-income countries. Included studies evaluated human papillomavirus vaccine, hepatitis A, hepatitis B, and varicella vaccines. Reported vaccine completion rates, among those who initiated vaccination, ranged from 27% to over 90%. Minority racial or ethnic groups and inadequate health insurance coverage were risk factors for low completion, irrespective of initiation rates. Parental healthcare seeking behaviour was positively associated with completion. Vaccine delivery in schools was associated with higher completion than delivery in the community or health facilities. Gender, prior healthcare use and socio-economic status rarely remained significant risks or protective factors in multivariate analysis. CONCLUSIONS: Almost all studies investigating factors affecting completion have been carried out in developed countries and investigate a limited range of variables. Increased understanding of barriers to completion in adolescents will be invaluable to future new vaccine introductions and the further development of an adolescent health platform. PROSPERO reg# CRD42014006765

Institutional logic meets global imagining: Kazakhstan’s engagement with China’s Belt and Road Initiative

Theoretical ideas about globalization and internationalization of higher education emphasize the tension among different ideologies of higher education. According to literature, a competition among states, economy, knowledge, and status generates this tension to drive higher education development. This theoretical understanding not only shapes our global imaginations but also permeates the organizational behavior of universities. In this paper, we focus on the institutional logics that motivate universities in Kazakhstan to engage with China’s ambitious Belt and Road Initiative (BRI). We investigate the ways that Kazakhstani higher education interprets and responds to China’s vision of a global order. Based on interviews conducted at 10 higher education institutions (HEIs) in Kazakhstan, we argue that Kazakhstan’s engagement with the BRI circumvents the cultural connectivity and global cooperation that are embraced by Chinese policy discourse and perpetuated by academic literature. Rather, institutional leaders in Kazakhstan operate with a utilitarian logic that seeks revenue generation, links with industry, and opportunities for students in employment and further education. The pursuit of these strategic outcomes demonstrates a bilateral engagement with China rather than the multilateral cooperation envisioned by policymakers. In a higher education system dominated by the state, the institutions in our study exhibit partial agency to accrue pragmatic benefits rather than concede to isomorphic pressures or mimic internationalization from neoliberal contexts. The discrepancy between policy discourse from China and policy reception in Kazakhstan raises questions about the rhetoric of a multipolar global order and the realities of international cooperation in higher education