Hot-headed peckers: thermographic changes during aggression among juvenile pheasants ( Phasianus colchicus )

In group-living vertebrates, dominance status often covaries with physiological measurements (e.g. glucocorticoid levels), but it is unclear how dominance is linked to dynamic changes in physiological state over a shorter, behavioural timescale. In this observational study, we recorded spontaneous aggression among captive juvenile pheasants ( Phasianus colchicus ) alongside infrared thermographic measurements of their external temperature, a non-invasive technique previously used to examine stress responses in non-social contexts, where peripheral blood is redirected towards the body core. We found low but highly significant repeatability in maximum head temperature, suggesting individually consistent thermal profiles, and some indication of lower head temperatures in more active behavioural states (e.g. walking compared to resting). These individual differences were partly associated with sex, females being cooler on average than males, but unrelated to body size. During pairwise aggressive encounters, we observed a non-monotonic temperature change, with head temperature dropping rapidly immediately prior to an attack and increasing rapidly afterwards, before returning to baseline levels. This nonlinear pattern was similar for birds in aggressor and recipient roles, but aggressors were slightly hotter on average. Our findings show that aggressive interactions induce rapid temperature changes in dominants and subordinates alike, and highlight infrared thermography as a promising tool for investigating the physiological basis of pecking orders in galliforms. This article is part of the theme issue ‘The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies’.

Analysis of operating parameters of the aircraft piston engine in real operating conditions

The article presents the results of analysis of operational parameters of piston engine CA 912 ULT which is a propulsion system of ultralight gyroplane Tercel produced by Aviation Artur Trendak. Research was conducted under normal operating conditions of the autogyro and data was collected from 20 independent tests including a total of 28 flight hours, divided into training flights and competition flights.Engine speed, manifold air pressure and temperature, fuel pressure, injection time, and head temperature were recorded at 9 Hz during each flight. Collective results were presented to show the statistical analyses of the individual parameters by determining the mean values, standard deviations and histograms of the distribution of these parameters. Histograms of operating points defined by both engine speed and manifold air pressure were also determined. Analyses of the engine dynamics as a distribution of the rate of change of the engine rotational speed were also carried out. It was shown that the engine operating points are concentrated mainly in the range of idle and power above 50% of nominal power. The most frequent range is 70-80% of nominal power. It was also shown that the dynamics of engine work in real operating conditions is small. It was also shown that the way of use significantly influences the distribution of operating points. During training flights, an increase in the number of take-offs and landings causes an increase in the amount of engine work at take-off and nominal power and at idle.

Pneumatic Microextrusion-Based Additive Biofabrication of Polycaprolactone Bone Scaffolds: Part II – Investigation of the Influence of Polymer Flow Parameters

Pneumatic micro-extrusion (PME), a direct-write additive manufacturing process, has emerged as a high-resolution method for the fabrication of a broad range of biological tissues and organs. However, the PME process is intrinsically complex, governed by complex physical phenomena. Hence, investigation of the effects of consequential parameters would be an inevitable need. The goal of this research work is to fabricate biocompatible, porous bone tissue scaffolds for the treatment of osseous fractures, defects, and eventually diseases. In pursuit of this goal, the objective of this study is to investigate the influence of material deposition factors — i.e., (i) deposition head temperature, (ii) flow pressure, and (iii) infill pattern — on the mechanical performance of PME-fabricated bone scaffolds. It was observed that the deposition head temperature as well as the flow pressure significantly affected scaffold diameter (unlike scaffold height). In addition, material deposition rate increased significantly as a result of an increase in the deposition temperature; this phenomenon stems from a reduction in Polycaprolactone (PCL) viscosity. Furthermore, there was a direct correlation between the amount of deposited mass and scaffold stiffness. Overall, the results of this study pave the way for future investigation of PME-deposited PCL scaffolds with optimal functional properties for incorporation of stem cells toward the treatment of osseous fractures and defects.

Experimental Study of Nanoscale Head-Disk Heat Transfer In Heat-Assisted Magnetic Recording

To study the nanoscale heat transfer and laser-related protrusions in heat-assisted magnetic recording (HAMR), we performed static touchdown experiments between HAMR waveguide heads and non-rotating media such as a silicon wafer and a recording disk with an AlMg substrate. During the static touchdown, the laser element is energized with DC current and the embedded contact sensor (ECS) is used to monitor the head temperature. The experimental results show that the thermal fly-height control (TFC) touchdown power decreases with increasing laser current. Meanwhile, the head temperature increases due to the laser heating. From this the ECS resistance rise induced by the laser is extracted. The results show that the silicon wafer dissipates heat effectively under the laser exposure, while the AlMg-substrate disk undergoes a higher temperature rise, which in turn heats the head.

Food Grains and Jaggery-based Expanded Food: Optimization of Process Variables, Protein Efficiency Ratio and Consumer Acceptability

Extrusion parameters for nutritious expanded food with jaggery were optimized following box-benken design using Response Surface Methodology. Jaggery and feed moisture affected physical properties, while nutritional and sensory properties of products were influenced by jaggery only. Optimized level of extrusion parameters consisted of 100 C die head temperature, screw speed of 304 rpm, 14 % moisture and 4 g jaggery per 100 g of formulation with 80 % maize, 14 % defatted soy-meal, and 6 % sesame-based formulation having overall desirability of 0.807. This expanded food showed expansion ratio of 3.57, 173.76 kg.m-3 bulk density, 15.18 % protein with 72.55 % invitro protein digestibility and 2.63 protein efficiency ratio, 1.97 % total minerals, 2.9 mg.100 g-1 iron, 158 mg.100 g-1 calcium with acceptability score of 8.2 that also indicated the consumer acceptability ≥7 by 95.37 % using 9-point hedonic scale.

Integration of multivariate control charts and decision tree classifier to determine the faults of the quality characteristic(s) of a melt spinning machine used in polypropylene as-spun fiber manufacturing Part I: The application of the Taguchi method and principal component analysis in the processing parameter optimization of the melt spinning process

Melt spinning is the most extensively used method of fabricating polymeric fibers in the textile industry. This series of studies aimed to construct an automatic abnormality diagnosis system for polypropylene (PP) as-spun fiber produced by the melt spinning process. Part I of this study aimed to construct the processing parameter optimization for the PP as-spun fiber produced by the melt spinning machine. The product quality resulting from the processing parameters of the melt spinning process included six control factors: extruder temperature, gear pump temperature, die-head temperature, rotational speed of extruder, rotational speed of gear pump, and take-up speed. The quality characteristics included fiber fineness, breaking strength, breaking elongation, and modulus of resilience. The quality data were derived from the experiments, the design of which were based on the orthogonal array of the Taguchi method in order to calculate the signal-to-noise ratio, analysis of variance, and confidence interval. Principal component analysis was then applied to eliminate the multi-correlation of the output responses and transform the correlated responses into principal components, to obtain multi-quality optimum processing parameters. These optimum parameters, including the extruder temperature (180°C), gear pump temperature (220°C), die-head temperature (240°C), the rotational speed of the extruder (7.5 rpm), the rotational speed of the gear pump (15 rpm), and take-up speed (700 rpm) would later be used to build a prediction of an abnormality diagnosis system for identification of fault processing parameters in a melt spinning machine in Part II of this study.

Experimental Optimization of Polymer Jetting Additive Manufacturing Process Using Taguchi Design

Polymer jet printing (PJP) is a direct-write additive manufacturing process, emerging as a rapid high-resolution method particularly in the medical field for the fabrication of a wide spectrum of products, e.g., anatomical models, tissue scaffolds, implants, and prosthetics. PJP allows for non-contact multi-material deposition of functional polymer inks. The PJP process centers on simultaneous deposition of build and support photopolymer materials on a free surface, which are immediately cured in situ using a UV light source, allowing for solid-freeform fabrication. The PJP process is inherently complex, governed by a multitude of parameters as well as material-machine-process interactions, which collectively affect the functional properties of a fabricated structure. Consequently, physics-based characterization and optimization of the PJP process would be inevitable. In this study, a new test standard was forwarded for the characterization of the mechanical properties of PJP-fabricated bone structures; the standard was designed on the basis of an X-ray p-CT scan of a femur bone in addition to the ASTM D638-14 standard. Furthermore, the Taguchi L8 orthogonal array design was utilized to investigate the effects of influential PJP process parameters on the mechanical properties of the bone structures, including Young’s modulus of elasticity, tensile strength, breaking strength, and ductility. The selected process parameters (each at two levels) were: (i) print direction, (ii) resolution factor, (iii) UV light intensity, and (iv) deposition head temperature. The mechanical properties of the femur bone structures were measured using a tensile testing machine. The UV light intensity appeared as the most significant factor, influencing all the aforementioned mechanical properties, while the resolution factor was identified as an inconsequential factor. In addition, it was observed that the print direction and the head temperature significantly affected the breaking strength and the ductility, respectively. Overall, the results of this study pave the way for further investigation of the effects of the PJP parameters toward optimal fabrication of complex bone tissue scaffolds and implants with long-lasting functional characteristics.

Influence of Internal Structure and Composition on Head’s Local Thermal Sensation and Temperature Distribution

A personalized thermal environment is an effective way to ensure a good thermal sensation for individuals. Since local thermal sensation and temperature distribution are affected by individual physiological differences, it is necessary to study the effects of physiological parameters. The purpose of this study was to investigate the effects of internal structures and tissue composition on head temperature distribution and thermal sensation. A new mathematical model based on fuzzy logic control was established, the internal structure and tissue composition of the head were obtained by magnetic resonance imaging (MRI), and the local thermal sensation (LTS) index was used to evaluate the thermal sensation. Based on the mathematical model and the real physiological data, the head temperature and local sensation changes under different parameters were investigated, and the sensitivity of thermal sensation relative to the differences in tissue thickness was analyzed. The results show that skin tissue had the highest influence ( C s k i n = 0.0180 ) on head temperature, followed by muscle tissue ( C m u s c l e = 0.0127 ), and the influence of adipose tissue ( C f a t = 0.0097 ) was the lowest. LTS was most sensitive to skin thickness variation, with an average sensitivity coefficient of 1.58, while the muscle tissue had an average sensitivity coefficient of 0.2, and the sensitivity coefficient of fat was relatively small, at a value of 0.04.