Fighter pilots’ teamwork: a descriptive study

The execution of teamwork varies widely depending on the domain and task in question. Despite the considerable diversity of teams and their operation, researchers tend to aim for unified theories and models regardless of field. However, we argue that there is a need for translation and adaptation of the theoretical models to each specific domain. To this end, a case study was carried out on fighter pilots and it was investigated how teamwork is performed in this specialised and challenging environment, with a specific focus on the dependence on technology for these teams. The collaboration between the fighter pilots is described and analysed using a generic theoretical model for effective teamwork from the literature. The results show that domain-specific application and modification is needed in order for the model to capture fighter pilot’s teamwork. The study provides deeper understanding of the working conditions for teams of pilots and gives design implications for how tactical support systems can enhance teamwork in the domain.

Practitioner summary: This article presents a qualitative interview study with fighter pilots based on a generic theoretical teamwork model applied to the fighter domain. The purpose is to understand the conditions under which teams of fighter pilots work and to provide guidance for the design of future technological aids.     

Processing-structure-property relations of chemically bonded phosphate ceramic composites

Mechanical properties and microstructures of a chemically bonded phosphate ceramic (CBPC) and its composite with 1.0 wt% graphite nanoplatelets (GNPs) reinforcement have been investigated. Microstructure was identified by using optical and scanning electron microscopes, X-ray tomography, and X-ray diffraction. In addition, weight loss of the resin at room temperature was studied. The microstructure characterization shows that CBPC is itself a composite with several crystalline (wollastonite and brushite) and amorphous phases. SEM and micro tomography show a homogeneous distribution of crystalline phases. Bending and compression strength of the CBPC was improved by reducing bubbles via preparation in vacuum.     

Chaperone‐like activity of β‐casein and its effect on residual in vitro activity of horseradish peroxidase

In this study, the residual activity horseradish peroxidase was used as a novel marker of chaperone‐like activity of β‐casein under elevated temperature. It was shown that β‐casein does affect residual activity of horseradish peroxidase (HRP) depending on the concentration and molar ratio between proteins. Incubating HRP (0.1 mg mL^?1) for 10 min at 72 °C resulted in residual activity of 59 ± 5%, while addition of 1 mg mL^?1 β‐casein resulted in increase in residual activity up to 85 ± 1%. Increased residual activity is not merely attributed to an effect of higher total protein concentration, as similar experiment with bovine serum albumin resulted in residual activity of horseradish peroxidase that was significantly lower than without any addition. The effect of β‐casein on HRP disappears when pH is below the isoelectric point of β‐casein. It was also proven by light scattering studies that β‐casein interacts with horseradish peroxidase when the temperature was increased from 25 to 70 °C whereas interactions seem to cease when temperature was lowered back to 25 °C. This study highlights how specific proteins can influence enzyme activity, which is of potential importance for various industries such as enzyme manufacturers and food industry.     

Cavitation Effects on Squeeze-Film Damper Performance

Experimental observations on unpressurized dynamically loaded hydrodynamic bearings and squeeze-film dampers indicate that cavitation bubbles, once formed, do not completely redissolve upon the reappearance of positive pressures. Instead, one is left with a spongy compressible fluid. Assuming this to be a homogeneous gas-liquid mixture, with density and viscosity dependent on pressure, the load capacity of squeeze-film dampers is compared with that obtained using hitherto adopted cavitation models which assume an incompressible lubricant with the fluid-film pressures being set to the saturated vapor pressure (SVP) of the lubricant whenever the pressure falls below the SVP. To save computation effort, a short bearing approximation is derived for the compressible Reynolds equation, so that comparisons apply to narrow dampers only (i.e. to dampers with length-to-diameter ratios less than 0.25). It is shown that for circular orbit squeeze-film dampers, best agreement is obtained with the incompressible model where the SVP is taken as zero absolute, though depending on the orbit eccentricity and the value of a dimensionless parameter called the squeeze number, commonly used π and 2π film cavitation models may also give excellent agreement.     

New type of micro-bipolar plate for micro-fuel cells using LIGA technology together with improved and cost-effective electroplating processes for PCBs

A new type of micro-bipolar plate for micro-fuel cells was developed. This micro-bipolar plate was realised using LIGA technology (laser lithography system) together with improved electroplating processes for printed circuit boards (copper, nickel, gold) to produce micro-fuel cells with reduced precious metal loading, increased activity and durability, lower weight and negligible corrosion, and, in addition, lower production cost.     

Effect of Interfacial Adhesion on the Mechanical Properties of Organic/Inorganic Hybrid Nanolaminates

Two different kinds of organic polyelectrolyte (PE)/inorganic silicate nanolaminates carrying dissimilar interfacial adhesion between the organic and the inorganic layers were prepared using the layer-by-layer self-assembly. To investigate the mechanical behavior of the prepared hybrid films, apparent modulus (E′), hardness (H), and crack length were measured by depth-sensing nanoindentation as well as a microVickers experiment. The fracture toughness of the hybrid films was then calculated based on the measured mechanical values. In the case of forming strong interfacial adhesion between the organic and the inorganic layers (A series), the fracture toughness and the crack resistance of hybrid multilayer films were significantly improved as a result of the redistribution of stress concentration and the dissipation of fracture energy by the plasticity of organic PE layers. On the other hand, samples with relatively low interfacial adhesion between the organic and the inorganic layers (T series) had little effect on the improvement of fracture toughness of the hybrid films.