Impact response and energy absorption of aluminium foam-filled tubes

The effect of foam fillers on the impact behaviour and energy absorption of an aluminium tube is investigated. Both experimental test and computational simulation are employed in current study. For comparison, hollow tubes and foams are also tested, respectively. Foam filler is found to be ineffective in increasing the crushing loads of the composite tubes over the simple superposition of the crushing loads of hollow tube and foam. Also, foam filler increases the tendency for the concertina mode of folding. The foam fillers of tubes additionally result in increasing the SAE values over those of hollow tubes.

Automotive engineering metal foam structures: fabrication, characterisation, testing and simulation

The contrubution of this thesis is to generate fundamental research and design information on the impact and bending behaviours of metal foams and foam-filled tubes

Temperature-dependence of mechanical properties of open-cell titanium foam

An open-cell titanium foam with relative density of 0.2 was prepared by powder metallurgical process. The compressive mechanical properties of the foam at the different temperatures in the range of 20-600°C were measured and the temperature-dependence of its mechanical properties was discussed. The results indicate that the foam material exhibit fragile fracture characteristic at room temperature. When it is deformed over 200°C, the stress-strain curves exhibit plastic deformation characteristic, including three distinct regions: the linear elasticity region, the plastic collapse region, and the densification region. The Young's modulus, yield stress and elastic limit decrease with increasing of temperature. The temperature-dependence of these properties can be expressed as E*=1.5217 × 10 9-5.988 × 10 5T, σ cl*=85.7-0.095T, σ ys*=99.1-0.167V7.02 × 10 -5T 2 respectively.

The cost-benefit of using soft silicone multilayered foam dressings to prevent sacral and heel pressure ulcers in trauma and critically ill patients: a within-trial analysis of the Border Trial.

Little is known about the cost-benefit of soft silicone foam dressings in pressure ulcer (PU) prevention among critically ill patients in the emergency department (ED) and intensive care unit (ICU). A randomised controlled trial to assess the efficacy of soft silicone foam dressings in preventing sacral and heel PUs was undertaken among 440 critically ill patients in an acute care hospital. Participants were randomly allocated either to an intervention group with prophylactic dressings applied to the sacrum and heels in the ED and changed every 3 days in the ICU or to a control group with standard PU prevention care provided during their ED and ICU stay. The results showed a significant reduction of PU incidence rates in the intervention group (P = 0·001). The intervention cost was estimated to be AU$36·61 per person based on an intention-to-treat analysis, but this was offset by lower downstream costs associated with PU treatment (AU$1103·52). Therefore, the average net cost of the intervention was lower than that of the control (AU$70·82 versus AU$144·56). We conclude that the use of soft silicone multilayered foam dressings to prevent sacral and heel PUs among critically ill patients results in cost savings in the acute care hospital.

A study on bending behaviours of aluminium foam-filled tubes

In the study, the strengthening effect of aluminium foam in thin-walled aluminium tubes subject to bending load in investigated experimentally and numerically. Bending tests are conducted on foam filler, hollow tube and foam-filled tube. The finite element method is used as well to get deeper insight into the crush failure modes via focusing on the influence from wall thickness of the tube. The obtained information is useful to optimally design foam-filled tubes as energy absorbing devices in automotive engineering. The optimisation results can be implemented to find an optimum foam-filled tube that absorbs the same energy as the optimal hollow tube but with much less weight. © (2014) Trans Tech Publications, Switzerland.

A randomised controlled trial of the effectiveness of soft silicone multi-layered foam dressings in the prevention of sacral and heel pressure ulcers in trauma and critically ill patients: The border trial

The prevention of hospital acquired pressure ulcers in critically ill patients remains a significant clinical challenge. The aim of this trial was to investigate the effectiveness of multi-layered soft silicone foam dressings in preventing intensive care unit (ICU) pressure ulcers when applied in the emergency department to 440 trauma and critically ill patients. Intervention group patients (n = 219) had Mepilex^® Border Sacrum and Mepilex^® Heel dressings applied in the emergency department and maintained throughout their ICU stay. Results revealed that there were significantly fewer patients with pressure ulcers in the intervention group compared to the control group (5 versus 20, P = 0·001). This represented a 10% difference in incidence between the groups (3·1% versus 13·1%) and a number needed to treat of ten patients to prevent one pressure ulcer. Overall there were fewer sacral (2 versus 8, P = 0·05) and heel pressure ulcers (5 versus 19, P = 0·002) and pressure injuries overall (7 versus 27, P = 0·002) in interventions than in controls. The time to injury survival analysis indicated that intervention group patients had a hazard ratio of 0·19 (P = 0·002) compared to control group patients. We conclude that multi-layered soft silicone foam dressings are effective in preventing pressure ulcers in critically ill patients when applied in the emergency department prior to ICU transfer.

Peripherally inserted central catheter cushioning: a pilot study comparing gauze with silicone foam

A pilot study was conducted to compare gauze with silicone foam that may be left in place for as long as seven days. Adult patients who were receiving treatment via peripherally inserted central catheters were recruited and alternately assigned to either the gauze or silicone foam group. Patient-reported itch and discomfort, nurse-reported ease of removal, and skin status were recorded for four weeks at each weekly dressing change.

Foam rolling for delayed-onset muscle soreness and recovery of dynamic performance measures

Context: After an intense bout of exercise, foam rolling is thought to alleviate muscle fatigue and soreness (ie, delayed-onset muscle soreness [DOMS]) and improve muscular performance. Potentially, foam rolling may be an effective therapeutic modality to reduce DOMS while enhancing the recovery of muscular performance. Objective: To examine the effects of foam rolling as a recovery tool after an intense exercise protocol through assessment of pressure-pain threshold, sprint time, change-of-direction speed, power, and dynamic strength-endurance. Design: Controlled laboratory study. Setting: University laboratory. Patients or Other Participants: A total of 8 healthy, physically active males (age = 22.1 ± 2.5 years, height = 177.0 ± 7.5 cm, mass = 88.4 ± 11.4 kg) participated. Intervention(s): Participants performed 2 conditions, separated by 4 weeks, involving 10 sets of 10 repetitions of back squats at 60% of their 1-repetition maximum, followed by either no foam rolling or 20 minutes of foam rolling immediately, 24, and 48 hours postexercise. Main Outcome Measure(s): Pressure-pain threshold, sprint speed (30-m sprint time), power (broad-jump distance), change-of-direction speed (T-test), and dynamic strength-endurance. Results: Foam rolling substantially improved quadriceps muscle tenderness by a moderate to large amount in the days after fatigue (Cohen d range, 0.59 to 0.84). Substantial effects ranged from small to large in sprint time (Cohen d range, 0.68 to 0.77), power (Cohen d range, 0.48 to 0.87), and dynamic strength-endurance (Cohen d = 0.54). Conclusions: Foam rolling effectively reduced DOMS and associated decrements in most dynamic performance measures.

Fabrication of graphene foam supported carbon nanotube/polyaniline hybrids for high-performance supercapacitor applications

A large-scale, high-powered energy storage system is crucial for addressing the energy problem. The development of high-performance materials is a key issue in realizing the grid-scale applications of energy-storage devices. In this work, we describe a simple and scalable method for fabricating hybrids (graphenepyrrole/ carbon nanotube-polyaniline (GPCP)) using graphene foam as the supporting template. Graphene-pyrrole (G-Py) aerogels are prepared via a green hydrothermal route from two-dimensional materials such as graphene sheets, while a carbon nanotube/polyaniline (CNT/PANI) composite dispersion is obtained via the in situ polymerization method. The functional nanohybrid materials of GPCP can be assembled by simply dipping the prepared G-py aerogels into the CNT/PANI dispersion. The morphology of the obtained GPCP is investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which revealed that the CNT/PANI was uniformly deposited onto the surfaces of the graphene. The as-synthesized GPCP maintains its original three-dimensional hierarchical porous architecture, which favors the diffusion of the electrolyte ions into the inner region of the active materials. Such hybrid materials exhibit significant specific capacitance of up to 350 F g^-1, making them promising in large-scale energy-storage device applications.

Facile fabrication of supercapacitors with high rate capability using graphene/nickel foam electrode

High-performance reduced graphene oxide/nickel foam (rGO/NF) composite electrodes for high-performance supercapacitors were prepared by flame-induced reduction of dry graphene oxide (GO) coated on nickel foam. Flame reduction of GO is a facile, feasible and cost-effective reduction technique, which is conducted without the need of any reductant. Most importantly, the rGO obtained by flame reduction showed a typical disordered cross-linking network and randomly distributed pores, which provide accessible routes for fast transportation of ions. It was demonstrated that the rGO/NF electrode with embedded current collector (NF) exhibited better electrochemical performance than conventional rGO film counterparts, including a high gravimetric specific capacitance of 228.6 F g-1 at a current density of 1 A g-1, excellent rate capability (over 81% retention at 32 A g-1) and high cycling stability with only 5.3% capacitance decay over 10,000 cycles of cyclic voltammetry at a ultrahigh scan rate of 1000 mV s-1. This facile method for the fabrication of rGO/NF electrodes could envision enormous potential for high performance energy storage devices.

Biocompatible and biodegradable Mg/Mg composite foam for bone tissue engineering.

This thesis focuses on studying solid and porous Magnesium-composite structures. Magnesium is attracting increasing interest as promising biodegradable material for medical applications; however, suffering from low mechanical properties. This thesis suggests the manufacturing and application of a new approach that is high str