Optimization Design of Laser Arrays Based on Absorption Spectroscopy Imaging for Detecting Temperature and Concentration Fields.

Detecting temperature and concentration fields within engine combustors holds paramount significance in enhancing combustion efficiency and ensuring operational safety. Within the realm of engine combustors, the laminar absorption spectroscopy technique has garnered considerable attention. Particularly crucial is the optimization of the optical path configuration to enhance the efficacy of reconstruction. This study presents a flame parameter field reconstruction model founded on laminar absorption spectroscopy. Furthermore, an optimization approach for refining the optical path configuration is delineated. In addressing non-axisymmetric flames, the simulated annealing algorithm (SA) and Harris's Hawk algorithm (HHO) are employed to optimize the optical path layout across varying beam quantities. The findings underscore a marked reduction in imaging errors with the optimized optical path configuration compared to conventional setups, thereby elevating detection precision. Notably, the HHO algorithm demonstrates superior performance over the SA algorithm in terms of optimization outcomes and computational efficiency. Compared with the parallel optical path, the optimized optical path of the HHO algorithm reduces the temperature field error by 25.5% and the concentration field error by 26.5%.

Simultaneous Reconstruction of Multiple Time-Varying Thermal Properties Based on Translucent Materials.

In the realm of high-tech materials and energy applications, accurately measuring the transient heat flow at media boundaries and the internal thermal conductivity of materials in harsh heat exchange environments poses a significant challenge when using conventional direct measurement methods. Consequently, the study of photothermal parameter reconstruction in translucent media, which relies on indirect measurement techniques, has crucial practical value. Current research on reconstructing photothermal properties within participating media typically focuses on single-objective or time-invariant properties. There is a pressing need to develop effective methods for the simultaneous reconstruction of time-varying thermal flow fields and internal thermal conductivity at the boundaries of participating media. This paper introduces a computational model based on the numerical simulation theory of internal heat transfer systems in participating media, stochastic particle swarm optimization algorithms, and Kalman filter technology. The model aims to enable the simultaneous reconstruction of various thermal parameters within the target medium. Our results demonstrate that under varying levels of measurement noise, the inversion results for different target parameters exhibit slight oscillations around the true values, leading to a reduction in reconstruction accuracy. However, overall, the model demonstrates robustness and accuracy in ideal conditions, validating its effectiveness.

Non-nutritive sucking relieves pain for preterm infants during heel stick procedures in Taiwan.

AIMS: This study examined the effectiveness of non-nutritive sucking on preterm infant pain, changes in infant behaviour and frequency of abnormal physiological signals during heel stick procedures in Taiwan. BACKGROUND: Preterm infants' repetitive exposure to painful procedures may result in changes to brain organisation. Pain management should be a priority in neonatal care. DESIGN: Randomised control trial. METHODS: Preterm infants (gestational age 28.9-37 weeks) were randomised to two groups: those receiving (experimental, n = 52) or not receiving non-nutritive sucking (control, n = 52) during heel stick procedures. Pain was measured before (for three minutes), during and after (during 10-minute recovery) heel stick procedures by the Premature Infant Pain Profile, changes in infant behaviour and abnormal physiological parameters. Results. Infants in both groups had similar odds ratios for pain and moderate-to-severe pain (0.57 and 0.58, respectively), after adjusting for time effects, postconceptional age, heel stick duration, painful experiences and baseline Premature Infant Pain Profile score. The pain scores of infants with non-nutritive sucking were significantly lower than those of non-nutritive sucking infants at all eight phases of the heel stick procedures. Infants undergoing heel stick procedures in the experimental group had lower rates ratios for 'grimace' and 'hand to mouth or face' behaviours than control infants (0.73 and 0.78, respectively). CONCLUSION: Non-nutritive sucking effectively reduced pain, particularly mild to moderate pain and behavioural responses to pain in infants receiving heel stick procedures, suggesting that nurses can offer this intervention to relieve pain in preterm infants undergoing invasive procedures. RELEVANCE TO CLINICAL PRACTICE: Infants should be given an appropriate-sized pacifier for comfort during painful procedures. Nurses need to be informed about the effectiveness of non-nutritive sucking, its analgesic mechanisms and how to use and incorporate it into practice.