Search Results (7)

In the pursuit of global energy conservation and emissions reductions, utilizing beverage cans as energy-absorbing components offers potential for a sustainable economy. This study examines the impact of foam filling on the crushing behaviors and energy absorption of various types of beverage cans. Quasi-static compression tests were conducted on five geometrically sized cans filled with three densities of polyurethane foam to study their deformation modes and calculate crashworthiness parameters within the effective stroke. Results show that empty beverage cans have lower energy absorption capacities, and deformation modes become less consistent as can size increases. Higher foam density leads to increased total energy absorption, a slight reduction in the effective compression stroke, and a tendency for specific energy absorption to initially increase and then decrease. Regarding crush behavior, smaller cans transition from a diamond mode to a concertina mode, while larger cans exhibit a columnar bending mode. Next, the coupling effect of energy absorption between foam and cans was analyzed so as to reveal the design method of energy-absorbing components. The specific energy absorption of smaller cans filled with polyurethane foam is superior to that of similar empty cans. These findings provide valuable insights for selecting next-generation sustainable energy absorption structures. Full article

With the ever-increasing role that nuclear power is playing to meet the aim of net zero carbon emissions, there is an intensified demand for understanding the thermal hydraulic phenomena at the heart of current and future reactor concepts. In response to this demand, the development of high-resolution flow analysis instrumentation is of increased importance. One such under-utilised and under-researched instrumentation technology, in the context of fluid flow analysis, is fibre Bragg grating (FBG)-based sensors. This technology allows for the construction of simple, minimally invasive instruments that are resistant to high temperatures, high pressures and corrosion, while being adaptable to measure a wide range of fluid properties, including temperature, pressure, refractive index, chemical concentration, flow rate and void fraction—even in opaque media. Furthermore, concertinaing FBG arrays have been developed capable of reconstructing 3D images of large phase structures, such as bubbles in slug flow, that interact with the array. Currently a significantly under-explored application, FBG-based instrumentation thus shows great potential for utilisation in experimental thermal hydraulics; expanding the available flow characterisation and imaging technologies. Therefore, this paper will present an overview of current FBG-based flow characterisation technologies, alongside a systematic review of how these techniques have been utilised in nuclear thermal hydraulics experiments. Finally, a discussion will be presented regarding how these techniques can be further developed and used in nuclear research. Full article

Expanded vermiculite (eVMT) has been studied as a risk-free, general-purpose absorbent for liquid hazards due to its excellent thermal and chemical stability. Here, vermiculite was expanded by two steps: exfoliation by 30 wt% H₂O₂ treatment at 60 °C and subsequent expansion by microwave heating. This two-step expansion produced more homogenously separated concertina-like eVMTs with a higher total pore volume of 7.75 cm³ g⁻¹ than the conventional thermal method. The two-step eVMT was found to be greatly superior to the thermal and commercial silver counterparts in hazardous liquid-uptake performance. The uptake was simply interpreted as a physical infilling process of a liquid into the eVMT pores, and the spontaneous hazard removal with a great capacity was discussed with the large pore volume of two-step eVMT and its suitable pore dimensions for capillary action. As a practical device, a prototype absorbent assembly made of these eVMTs demonstrated the successful mitigation of liquid hazards on an impermeable surface. Full article

In the viper boa (Candoia aspera), the cerebrospinal fluid (CSF) shows two stable overlapping patterns of pulsations: low-frequency (0.08 Hz) pulses with a mean amplitude of 4.1 mmHg that correspond to the ventilatory cycle, and higher-frequency (0.66 Hz) pulses with a mean amplitude of 1.2 mmHg that correspond to the cardiac cycle. Manual oscillations of anesthetized C. aspera induced propagating sinusoidal body waves. These waves resulted in a different pattern of CSF pulsations with frequencies corresponding to the displacement frequency of the body and with amplitudes greater than those of the cardiac or ventilatory cycles. After recovery from anesthesia, the snakes moved independently using lateral undulation and concertina locomotion. The episodes of lateral undulation produced similar influences on the CSF pressure as were observed during the manual oscillations, though the induced CSF pulsations were of lower amplitude during lateral undulation. No impact on the CSF was found while C. aspera was performing concertina locomotion. The relationship between the propagation of the body and the CSF pulsations suggests that the body movements produce an impulse on the spinal CSF. Full article

This paper analyzed the locomotion of a snake robot in narrow spaces such as a pipe or channel. We developed a unique experimental snake robot with one revolute and one linear joint on each module, with the ability to perform planar motion. The designed locomotion pattern was simulated in MATLAB R2015b and subsequently verified by the experimental snake robot. The locomotion of the developed snake robot was also experimentally analyzed on dry and viscous surfaces. The paper further describes the investigation of locomotion stability by three symmetrical curves used to anchor static modules between the walls of the pipe. The stability was experimentally analyzed by digital image correlation using a Q-450 Dantec Dynamics high-speed correlation system. The paper presents some input symmetrical elements of locomotion and describes their influence on the results of locomotion. The results of simulations and experiments show possibilities of snake robot locomotion in a pipe. Full article

The Great Orbital Run was a solitary run/artwork that took place over nine days around the inside boundary of the M25 London Orbital. The journey was mapped through a stream of photographs and GPS coordinates relayed live from a mobile phone to a web interface and shown as a projected artwork at the University of Greenwich, London. It was later re-configured as the M25 in 4000 images, a unique concertina bookwork/sculpture produced from digital data into tangible, printed paper form. Cut, folded, and constructed by hand, it makes visible the mass of images that embody the running activity and the terrain it represents. This essay considers this artwork and its status as a document and artist’s book, reflecting on (1) the original running activity, (2) the mapping of the boundary of Greater London, (3) the performance of technology in relaying the run, and (4) the transformation of digital images into material form. The document is considered in relation to the run as a performance and in relation to its performative potential. This is extended to the documentary properties of the artists’ book as ‘a form of three-dimensional representation’ that, through its ‘agency’, aligns itself with spatial practice. Full article

Most of the current snake-like robots can only work in a specific environment, or only have a good movement effect in a certain gait. This paper presents a design for a snake-like robot to improve the adaptability of various environments. Each standard module of the snake-like robot has three degrees of freedom: yawing, rolling, and telescoping. The envelope passive wheels are used to enable the robot to move in complex environments such as a narrow passage. We verified some simple movements such as serpentine movement and rectilinear movement and designed a method for recovering from rollover when the robot is in straight state. In addition, two novel gaits, obstacle-aided concertina gait, and obstacle-aided gait through narrow corner, are proposed in this paper. We demonstrated the feasibility for passing the narrow corner by these gaits in experiments. Full article