Search Results (4)

This paper presents an experimental study of wave motions and a global diagnostics method in a realistic aerospace-grade composite component with a complex design. Due to the frequency dependence of the velocity, wave propagation in anisotropic materials is difficult to describe quantitatively. The analysis of experimental ultrasonic wave propagation and the interactions with discontinuities in thin-walled aircraft structures can provide a plethora of information on the wave structure, the mode shapes, and stiffness reduction. An experiment is devised with a network of various omnidirectional sensor configurations to activate and measure structural responses. The measurement process can be leveraged for flaw detection in large multilayered structures. Physically, this corresponds to analyzing the dispersive behavior and scattering properties of ultrasonic waves, the shape of the waveforms, and their corresponding velocities. Ultrasonic waves are measured in a realistic CFRP fuselage panel in a pristine state and after impacts at different energy levels. Simulations do not allow the wave motion in complex and large design structures to be entirely comprehended. The sensitivity of the guided waves as a damage detection tool is proved for the fuselage structure by an extensive measurement campaign and a probabilistic imaging approach based on health indicator fusion. Full article

The exponential rise of bacterial resistance poses a threat to antibiotic efficacy, with a great impact on public health. This study aims to analyze the correlation between antibiotic consumption and the emergence of bacterial resistance. Conducted retrospectively at Charles Nicolle Hospital in Tunis, Tunisia, from 2010 to 2022, this study was based on STKMED^® software for antibiotic consumption data, hospital administrative records for the number of hospitalization days, and SIRSCAN^® software for bacteriological data. Data processing was performed using Excel^® software version 2019, and analysis was conducted using SPSS23^®. In 2022, consumption was almost evenly split between the two major “AWaRe” groups, with 49.33% for “Access” and 46.89% for “Watch”, and the consumption of the “Reserve” group also increased, accounting for 3.77% of the total. Bacterial resistances, notably carbapenem-resistant Klebsiella pneumoniae, increased. Seventy-four significant correlations were identified, including those between carbapenem consumption and resistance in Escherichia coli and Klebsiella pneumoniae strains. However, no significant correlation was observed with imipenem-resistant Pseudomonas aeruginosa strains. The significant correlations between the emergence of bacterial resistance and antibiotic use, particularly with antibiotics in the “Watch” and “Reserve” groups, underscore the urgent need to continue efforts to combat this threat through rational antibiotic use. Full article

This study analyzes the research associated with higher education during the COVID-19 pandemic in the Gulf Cooperation Council (GCC) region, offering an overview of papers published in Sustainability by utilizing the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). The analysis comprised a total of 17 papers, illuminating a number of common features, thematic foci, and prevailing issues as well as recommendations for rethinking higher education delivery in the future. Briefly, the analysis of common features revealed that most of the papers were published in 2021, researchers were mostly affiliated with higher education institutions in Saudi Arabia, data were mostly collected from undergraduate students, and papers were mostly quantitative. Regarding thematic focus, papers were generally related to teaching, learning, and assessment. As for prevailing issues, results highlighted a lack of practical studies in higher education research in the GCC region and a need for extending the conducted research to further context including other countries and populations. Finally, the key recommendations included improvement in the use of information technology and distance learning tools, as well as the design of policies and regulations to ensure more relevant academic intervention and guidelines for utilizing the tools and technologies. Full article

This study aimed at the evaluation of a simplified Italian matrix test (SiIMax) for speech-recognition measurements in noise for adults and children. Speech-recognition measurements with adults and children were conducted to examine the training effect and to establish reference speech-recognition thresholds of 50% (SRT50) and 80% (SRT80) correct responses. Test-list equivalency was evaluated only with adults. Twenty adults and 96 children—aged between 5 and 10 years—participated. Evaluation measurements with the adults confirmed the equivalence of the test lists, with a mean SRT50 of −8.0 dB and a standard deviation of 0.2 dB across the test lists. The test-specific slope (the average of the list-specific slopes) was 11.3%/dB, with a standard deviation of 0.6%/dB. For both adults and children, only one test list of 14 phrases needs to be presented to account for the training effect. For the adults, adaptive measurements of the SRT50 and SRT80 showed mean values of −7.0 ± 0.6 and −4.5 ± 1.1 dB, respectively. For children, a slight influence of age on the SRT was observed. The mean SRT50s were −5.6 ± 1.2, −5.8 ± 1.2 and −6.6 ± 1.3 dB for the children aged 5–6, 7–8 and 9–10 years, respectively. The corresponding SRT80s were −1.5 ± 2.7, −3.0 ± 1.7 and −3.7 ± 1.4 dB. High test–retest reliabilities of 1.0 and 1.1 dB for the SRT80 were obtained for the adults and children, respectively. This makes the test suitable for accurate and reliable speech-recognition measurements. Full article