A fluid-driven soft robotic fish inspired by fish muscle architecture

Artificial fish-like robots developed to date often focus on the external morphology of fish and have rarely addressed the contribution of the structure and morphology of biological muscle. However, biological studies have proven that fish utilize the contraction of muscle fibers to drive the protective flexible connective tissue to swim. This paper introduces a pneumatic silicone structure prototype inspired by the red muscle system of fish and applies it to the fish-like robot named Flexi-Tuna. The key innovation is to make the fluid-driven units simulate the red muscle fiber bundles of fish and embed them into a flexible tuna-like matrix. The driving units act as muscle fibers to generate active contraction force, and the flexible matrix as connective tissue to generate passive deformation. Applying alternant pressure to the driving units can produce a bending moment, causing the tail to swing. As a result, the structural design of Flexi-Tuna has excellent bearing capacity compared with the traditional cavity-type and keeps the body smooth. On this basis, a general method is proposed for modeling the fish-like robot based on the independent analysis of the active and passive body, providing a foundation for Flexi-Tuna’s size design. Followed by the robot’s static and underwater dynamic tests, we used finite element static analysis and fluid numerical simulation to compare the results. The experimental results showed that the maximum swing angle of the tuna-like robot reached 20°, and the maximum thrust reached 0.185 N at the optimum frequency of 3.5 Hz. In this study, we designed a unique system that matches the functional level of biological muscles. As a result, we realized the application of fluid-driven artificial muscle to bionic fish and expanded new ideas for the structural design of flexible bionic fish.

Numerical and Experimental Investigation of a Non-Premixed Double Swirl Combustor

This paper focuses on a detailed numerical investigation combined with experimental research for a non-premixed swirl combustor, which aims to analyze the effects of the blade angle of the outer swirler and equivalence ratio on flow and combustion characteristics. In the experiment, the temperature in the furnace was obtained with a thermocouple, while a realizable k-ε turbulence model and two-step reaction mechanism of methane and air are used in the numerical method. The calculation results are in good agreement with the experimental data. The results reveal that the air flow rate through the swirler accounts for a small amount of the total air due to the influence of the draft fan, and there is no central recirculation zone (CRZ) despite the presence of the swirler. It was also found that NO emissions gradually decrease as the blade angle of the outer swirler increases. It was also indicated that the average temperature is 100 K higher than the general combustor with a 58° blade angle in the furnace by increasing the equivalent ratio of the tertiary air area, and the NO emissions reduced by approximately 25%. This study can provide guidance for the operation and structural design of non-premixed swirl combustors.

Experiential design on cause-related marketing: lessons from the fill-the-bottle challenge

Purpose Based on a “Fill-the-Bottle” (FTB) challenge, this research explores how experiential design can help cause-related marketing. This study aims to show that experiences designed as anti-structural and anti-functional can raise awareness through action. Design/methodology/approach The authors study a corpus of 52 introspective journals and 60 pictures about the challenge, which entails filling empty bottles with cigarette butts from the streets as quickly as possible, then sharing pictures of the bottles on social media. Findings The anti-structural design of the experience activates the participants’ experiential system, and the social interactions between the participants and pedestrians construct meaning for the experience. The results further indicate that as follows: individuals’ frames of reference can explain whether they perceive the experience as liberatory or stochastic; anti-structural design can serve cause-related marketing by focusing on three stages: doing, showing and sharing; and experiential marketing can serve societal and social causes. Research limitations/implications This research involved a single field. Further research with more heterogeneous participants would be insightful. The power of experiential marketing to serve meaningful and collective causes should be encouraged. Further research should be conducted to understand and conceptualize these collective attempts to fight the dark sides of consumption. Practical implications In line with Pine and Gilmore’s (1999) advice to stage memorable experiences by working cautiously on cues, the FTB challenge analysis indicates that by focusing on material evidence and staging a specific sequence of doing something about it, showing everyone what is being done and expanding visibility by sharing artifacts of the action on social media, one can actually make people think about and remember the action. Social implications The “do-show-share” design that the FTB challenge uses can be relevant for many cause-related marketing efforts because it operates on both individual and collective levels. Originality/value This research offers a new perspective on experiential marketing by studying how experiences designed to be anti-structural can renew social, cause-related marketing tools.