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Chew Chai

Publications and source records attributed to Chew Chai.

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A Field Biology Guide for the Curious Physicist

Fieldwork is an essential component not just for organismal biology but also for the expanding umbrella of disciplines that have turned their attention toward the physics of living systems. Observing organisms in nature is a critical component of discovery; however, conducting field research can be a barrier for scientists who do not have experience working with organisms under challenging field conditions. Here, we propose 7 critical steps for organizing and executing interdisciplinary, curiosity-driven field research. Our steps are drawn from insights gained from the in Situ Jungle Biomechanics Lab (JBL), a field research course that helps early-career scientists from both physical and life sciences gain experience in both organizing and conducting interdisciplinary field research in the Amazon Rainforest. We emphasize a curiosity-driven approach towards the scientific inquiry of living systems, one we believe is crucial for discovery while working with wild organisms under highly unpredictable field conditions. We further provide guidance on teamwork when conducting fieldwork, including creating an inclusive environment and advocating for codes of conduct and team structures that aid in conflict resolution. Finally, we outline what we call the in situ approach to fieldwork, one that requires engagements with the environment, scientific community, and local peoples where field sites exist.

q-bio.OT

Interfacial mechanisms for stability of surfactant-laden films

Thin liquid films are central to everyday life. They are ubiquitous in modern technology (pharmaceuticals, coatings), consumer products (foams, emulsions) and also serve vital biological functions (tear film of the eye, pulmonary surfactants in the lung). A common feature in all these examples is the presence of surface-active molecules at the air-liquid interface. Though they form only molecularly-thin layers, these surfactants produce complex surface stresses on the free surface, which have important consequences for the dynamics and stability of the underlying thin liquid film. Here we conduct simple thinning experiments to explore the fundamental mechanisms that allow the surfactant molecules to slow the gravity-driven drainage of the underlying film. We present a simple model that works for both soluble and insoluble surfactant systems. We show that surfactants with finite surface rheology influence bulk flow through viscoelastic interfacial stresses, while surfactants with inviscid surfaces achieve stability through opposing surface-tension induced Marangoni flows.

physics.flu-dyn