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© 2019 Elsevier Ltd This article presents experimental and numerical results following blast tests on a polyether grade thermoplastic polyurethane (TPU). Aluminium alloy (AA) 2024-T3 skins were used as facings to enhance the blast resistance of sandwich structures with TPU cores and varying thicknesses. The experimental results highlighted an improvement in blast resistance with the addition of skins to the TPU core. Increasing the thickness of the TPU core in the sandwich panels served to increase the blast resistance of the structure. For example a 20 mm core offered a blast resistance that was 50.2% higher than an equivalent 5 mm core and 71.2% higher than a plain (i.e. no skin) 5 mm TPU core. Numerical simulations of the blast response of the TPU panels were conducted by converting the explosive loading regime applied to the panels to a simplified pressure pulse loading. Good agreement was obtained between the numerical and experimental results for the back face deflection profiles through the central cross-sections of the panels.

The mining activities significantly lower the sustainability in the stone mining region. Cleaner production (CP) is more likely to be proposed to achieve the sustainable development in the mining regions. Therefore, the stone mining industry has begun to implement many CP technologies and initiatives to tackle with ecological problems caused by the mining production. However, the CP practices do not solve the problems sufficiently, because of the low level of implementations by the stone mining companies, especially in the developing countries. This paper aims to establish a support framework for the stone mining industry to develop reasonable CP strategy and avoid inefficient CP practices. Our research provides a methodology for evaluating the CP level, including the principles of establishing indicator and standard system, the method of developing evaluation algorithm and the approach of data collection. A CP evaluation system is developed for the first time in the stone mining industry, which enables the methodology to be operationalization in the real evaluation process. The study also introduced the sensitivity analysis and confidence interval (ci) theory to ensure the reliability of the system and the validity of the evaluation results, respectively. A case study in Laizhou region of China illustrates how a CP strategy develops based on the CP evaluation results. The strategy has achieved collaborative optimization of various indexes of sustainability performance in the mining region.

In order to increase the service life and maintain the residual strength of damaged composite structures, it is necessary to investigate effective repairing techniques. In this paper, an innovative stitch-reinforced scarf patch is developed in order to reduce the amount of parent material that is removed during the repair. Carbon fibre threads are used to stitch the scarf patch to a damaged carbon fibre laminate via pre-drilled holes. Following stitching, the vacuum resin infusion technique is used to infuse the carbon fibre threads, thereby fixing the patch to the parent part. Here, the effects of varying both the hole diameter and the scarf angle on the load-carrying capacity of the repaired laminates are studied. The tensile strength, strain distribution and failure mechanisms are investigated using the digital image correlation (DIC) technique. The results show that by introducing a 2.5 mm diameter stitching hole, the ultimate tensile strength of repaired laminates related to three scarf angles is increased by up to 20, 27 and 45% respectively, relative to traditional laminates with an equivalent scarf ratio.

This chapter covers pertinent issues around the management of children with status epilepticus within and outside of specialist centres. A detailed overview of the work-up of a child in status epilepticus is presented. Additionally, the potential management of patients with refractory status epilepticus and super-refractory status epilepticus is evaluated. Furthermore, the chapter focuses on strategies to aid decision-making related to the practical challenges paediatric intensivists face, such as the suitability of extubating patients at the referring hospital, the decision to transfer patients to specialist centres for ongoing management, the role of neuroimaging, and about use of quantitative electroencephalogram (EEG) as a continuous neuromonitoring modality.

This paper presents a study focusing on the perforation resistance of glass fibre-reinforced PEKK composites. Woven S-glass fibre (GF) reinforced poly-ether-ketone-ketone (PEKK) thermoplastic prepreg materials were manufactured using a dry powder prepregging method. Prior to impact testing and modelling, the properties of the composites were evaluated by conducting a series of quasi-static tests at room and elevated temperatures. Quasi-static tensile and perforation tests showed that the optimum weight fraction of PEKK, wf, is approximately 0.4, which gives the peak tensile strength and perforation resistance. Tests at elevated temperatures highlighted the excellent stability of these materials under extreme conditions. As expected, the energy required to perforate the targets increased with projectile diameter. Subsequent tests highlighted the severity of conically-shaped projectiles with the perforation resistance dropping under sharp object impact loading. A series of finite element models were also developed to predict the response of the glass fibre/PEKK composites to impact by projectiles based on different diameters and shapes. The predictions were validated against the experimental force-displacement traces and failure modes with good agreement.

The behaviour of concrete filled steel tube (CFST) columns has been investigated intensively against lateral and axial impact loading. However, there is a lack of knowledge on the impact response of the connection between such the column and steel beam. In order to close this gap, the most common connections with a partial depth end plate (PDEPCs), as a simple connection, and a flush plate (FPCs), as a moment resisting connection, were investigated under lateral impact loads. The long bolts were used to connect the CFST column to the beam as an alternative technique to the ordinary bolts. Here, eight specimens were tested under loading conditions with different locations and plate thicknesses. 3D finite element models were then developed and validated against the corresponding experimental results. Full range analyses of the connection response under the loading regime were then carried out using the validated FE models to examine the internal forces and the energy dissipation of the connections. The main findings are as follows: (1) the failure modes of both connection types investigated were similar at both loading locations only with slightly higher tearing fracture on the PDEPC; (2) using a thicker end plate increases the moment capacity of the connection but decreases its energy absorption; (3) the performance of long bolts provides the connection with appropriate ductility up to failure.

Lightweight cores, based on an egg-box core design, have been manufactured using a simple compression-moulding technique. Two types of composite prepreg were used to manufacture the core materials, these being a woven carbon fibre reinforced epoxy and a woven glass fibre reinforced epoxy. The resulting cores were of a high quality, exhibiting little or no wrinkling following the manufacturing procedure. Subsequent compression tests at quasi-static rates of loading showed that the compression strength of the core depended strongly on the level of constraint applied during testing, with sandwich panels based on composite skins bonded to an egg-box core offering a load-bearing capability that was more than double that of its unconstrained counterpart. The quasi-static compression strength of the carbon-based cores has been shown to be slightly higher than the glass fibre systems, particularly at higher core densities. Local splitting damage at cell joining regions and crushing of the cell of the egg-box structure was identified as the primary failure mechanism in the sandwich panels. Impact tests, conducted using a drop-weight impact tower, have shown that the compression strength of the egg-box cores is higher at dynamic rates of loading than at quasi-static rates. Here again, the local splitting and crushing was the primary mode of failure in the sandwich structures. Finally, the finite element technique has been used to model the mechanical response of these core designs under both quasi-static and impact loading testing conditions. Here, agreement between the predicted and observed responses was found to be good for both extremes of loading-rate.

Reliably predicting and estimating roof collapse in underground cavities such as mine goafs and power caverns is a serious concern in mining and geotechnical engineering fields. An analytical expression for a three-dimensional (3D) failure mode of a generic-shaped cavity crown is derived according to the upper bound theorem via limit analysis, where the Hoek-Brown yield criterion represents rock mass strength. The proposed method is validated by comparison against the extant research; the comparison also suggests that the roof profile plays a crucial role in cavity stability. Specific example is given to ellipsoidal cavity and the stability graph with respect to roof profile and cavity span is obtained and discussed. The effects of numerous factors on potential collapse are investigated based on the numerical calculation results. These results may provide workable guidelines for the optimization of roof shapes and support designs in minimizing rock detachment above cavity roofs in practice.

This paper presents a study on the mechanical properties of spherical egg-box core sandwich panels subjected to compression. Initial attention focuses on the effect that constraining the core, via the introduction of skins, and increasing the thickness of the cell walls has on the compressive properties of GFRP and CFRP structures. Tests were also undertaken on foam-filled samples in order to investigate the influence of additional support on the crushing behaviour of the cores. Low velocity impact tests were subsequently undertaken in order to investigate the rate-sensitivity of these core structures. Finally, blast tests were conducted on the core materials to investigate their response at high strain rates. It has been shown that constraining the lateral movement of the cores, by bonding composite skins to the upper and lower surfaces, serves to enhance the mechanical properties of the core in compression. In addition, quasi-static compression testing has shown that the compressive strength of the core increases rapidly with increasing cell wall thickness, with effects being more pronounced in the GFRP structures. Tests on foam-filled panels have shown that adding a low density filler to the core serves to enhance the energy-absorbing properties of the GFRP systems. Subsequent tests at dynamic rates of loading have shown that the values of energy absorption were slightly higher than those measured at quasi-static rates, due to rate effects in the failure processes within the composite material. Finally, it has been shown that when subjected to blast loading, extensive crushing of the spherical egg-box was observed, indicating that these structures are capable of absorbing significant energy under this extreme loading condition.

We presented the employment of ascorbic acid as the reducing agent for the in situ deposition of Ag nanoparticles on the surface of TiO2 nanotube arrays (TiO2 NTs/Ag). The structural investigation by scanning electron microscopy and transmission electron microscopy indicated that Ag nanoparticles with average diameters of 15 nm uniformly grew on TiO2 NTs walls. The possible formation mechanism of TiO2 NTs/Ag was proposed. UV–vis absorption and photoelectrochemical measurements indicated that the Ag sensitization extended the visible light absorption region, improved the photocurrent response, and enhanced solar-induced photoelectrocatalytic activities.

In order to improve the inherent brittleness of the conventional coarse-grained YAG transparent ceramics, nano-grained YAG transparent ceramics were fabricated at 5 GPa/450 °C using the super high pressure sintering technique. Their mechanical properties were investigated by nanoindentation and the Vickers indentation measuring methods. It was found that the nano-grained YAG transparent ceramics exhibited much better ductility compared with the coarse-grained counterparts. The grain-boundary sliding provides the main contribution to plastic deformations of nano-grained YAG transparent ceramics. Keywords: Nano ceramics, YAG, Nanoindentation, Mechanical property, Toughness

TiO2 nanotube arrays (TiO2 NTs) were prepared by a two-step anodization of titanium foils in ethylene glycol electrolyte. Then, CdS and Bi2S3 nanoparticles were deposited on TiO2 NTs by an one-pot solvothermal method. The investigations of X-ray diffraction and scanning electron microscopy indicated that CdS and Bi2S3 nanoparticles grew uniformly on the surface of TiO2 NTs. UV–vis absorption and photoelectrochemical measurements proved that the CdS and Bi2S3 co-sensitization significantly improved the visible light absorption, photocurrent response and photoelectrocatalytic removal of RhB and Cr(VI). In addition, the influence of Cd2+/Bi3+ concentration ratios on the photoelectrochemical performance of TiO2 NTs-CdS/Bi2S3 was investigated in detail. The TiO2 NTs-CdS/Bi2S3 (1:1) showed an optimal photoelectrochemical activity which could be attributed to the improvement of visible light response and charge separation derived from the coupling effect of CdS/Bi2S3 nanoparticles.

Based on microsensor technology, a novel test rig was developed for the first time to measure real-time multi-point temperatures and relative humidities inside a cricket helmet worn by a human subject for obtaining the corresponding thermal and moisture mapping. Two types of helmets with and without ventilation openings were investigated to visualise the hot and wet spots clearly inside the helmet. The results show the clear influence of ventilation openings on effective reduction of the temperature as well as the relative humidity inside the helmet. Also, the subjective data were linked to the digital temperature and relative humidity measurements for possible assisting design of helmet with improved thermal comfort. The technology developed is a useful measurement approach to other head gears such as safety, fire fighter and motorcycle helmets, and further to study microclimate environments in close contact with human body.

Roll plane fluid slosh within a partly-filled tank with an elastic membrane restraining the free surface is investigated through development of a two-dimensional computational fluid dynamic and fluid-structure interaction (CFD-FSI) model. The air-membrane-liquid interaction analysis is performed to investigate effect of the membrane on the liquid cargo movement. Laboratory experiments were conducted on a circular tank with an elastic membrane-like restraint under harmonic lateral acceleration excitations. The validity of the CFD-FSI model is demonstrated on the basis of the laboratory-measured responses. The effectiveness of the membrane in limiting the fluid slosh is illustrated by comparing simulation results obtained for a circular tank with and without the membrane. It is shown that addition of the membrane could yield substantial reduction in the fluid cargo motion and thus roll moment, while increasing the fundamental slosh frequency by more than two times that obtained for the cleanbore tank.

TiO2 nanotube arrays sensitized with Sb2S3 microcrystalline were successfully fabricated by a two-step process of photodeposition method followed by annealing treatment. The structural investigation by X-ray diffraction, scanning electron microscopy and transmission electron microscopy indicated that the Sb2S3 microparticles grew uniformly on the walls of TiO2 nanotubes. The amorphous Sb2S3 microspheres could be transformed into octahedral microcrystals after annealing treatment. The Sb2S3 modification of the TiO2 nanotube arrays resulted in an increase in visible light adsorption and photocatalytic activities toward degradation of methyl orange (MO) and rhodamine B (RhB) dyes under visible light irradiation.

In this work, we developed a novel environmentally friendly strategy toward solvothermal synthesis of 3D hierarchical Cu2FeSnS4 microspheres with the utilization of l -cystine, an amino acid, as a coordination agent and sulfur donor. The crystal structure, surface morphology and microstructure of the as-prepared products were investigated. The results showed that the 3D hierarchical Cu2FeSnS4 microspheres were composed of stannite nanosheets, and the average thickness of nanosheets was 100 nm. Moreover, the 3D hierarchical Cu2FeSnS4 exhibited high efficiency in the photodegradation of RhB under visible light illumination, suggesting a promising candidate for treatment of organic pollutants in waste water.

In order to comparatively assess near-neutral pH stress corrosion cracking (NNpH-SCC) resistance of pipeline steels with different strength, constant load tests in NS4 solution purged with 5%CO2–N2 gas mixture were conducted on American Petroleum Institute (API) grade X70, X80 and X100 pipeline steels. Experimental results show that pit cracks appeared on the surface of X70 steel and non-pit cracks appeared on X100 steel. However, for X80 steel both pit cracks and non-pit cracks were observed, but pit cracks dominated. The near-neutral pH SCC resistance decreased in the order of X70, X100 and X80 at the same applied stress level.

Ag nanoparticles modified TiO2 nanotube arrays (TiO2 NTs/Ag) were fabricated by a simple solvothermal method using ethanol as solvent and AgNO3 as precursor. The composition and structural investigation by X-ray diffraction, scanning electron microscopy and UV–vis diffusion reflection spectroscopy indicated that Ag nanoparticles were deposited into the TiO2 NTs. The TiO2 NTs/Ag exhibited more excellent photoelectrochemical and photocatalytic activities than those of the TiO2 NTs under UV and visible light irradiation. The enhanced photoelectrochemical activity of the TiO2 NTs/Ag could be attributed to the improvement of surface plasmon resonance absorption and charge separation derived from Ag nanoparticles.

The behaviour of different steel beam to column connections has been studied intensively against static and seismic loading regimes. However, there is a lack of knowledge on the response of such connections against impact and blast. In order to close this gap, the most common connections with partially depth end plate (PDEPCs), as a simple connection, and flush plate (FPCs), as a moment resisting connection, were investigated under both quasi-static and impact loads. Here, eight specimens were tested under those loading conditions with different locations. 3 D finite element models were then developed and validated against the corresponding experimental results. Full range analyses of the connection responses under both loading regimes are then carried out using the validated FE models to examine the internal forces of the connections. Finally, the results of full analyses under both loading regimes were compared and dynamic increase factors (DIF) were proposed to assist predicting the impact response of these types of connections using the static analysis. The results showed that failure modes under both loading regimes were similar, but with the larger fracture on the PDEPC under quasi-static load than that under lateral impact. The DIFs were found to be between 1.02 and 1.21, 1.03 and 1.36 and 1.22 and 1.45 based on the bolt tensile strength, axial resistance and bending resistance of the connections, respectively. However, if based on the energy approach, the range of DIFs was recorded between 1.25 and 1.38 using the experimental results and between 1.19 and 1.34 using the finite element analysis results.