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Abstract Background Intensive care unit (ICU) nurses are at high risk of burnout and warranting attention. Existing literature found that work frustration was related to burnout, whilst perceived organization support influenced the association of work frustration with burnout. The purpose of this study was to investigate the relationship of work frustration and burnout among ICU nurses, and to examine the moderating effect of perceived organization support in their relationship. Methods The cross-sectional study was conducted with a convenience sample of 479 ICU nurses from several 3 tertiary hospitals during December 2021 to May 2022. The Maslach Burnout Inventory-Human services survey (MBI-HSS), National Aeronautics and Space Administration Task Load Index (NASA-TLX) and perceived organization support Scale (POSS) were used to collect data. The PROCESS macro was performed to test the moderation effect of perceived organization support. Results The total score of burnouts was (55.79 ± 17.20), the total score of work frustration was (7.44 ± 1.86). Burnout was positively correlated with work frustration (r = 0.301, P

Frozen soil will inevitably bear dynamic loads (impact and blasting) in the construction process in cold regions; the investigation of dynamic energy dissipation characteristic of ice-rich frozen soil is beneficial to optimize blasting parameters and the design of underground explosion-proof structure. In this study, the dynamic impact laboratory tests were conducted for frozen sandy soil with various water contents (from 15% to 110%) and strain rates (from 450 s-1 to 728 s-1) based on the split Hopkinson pressure bar (SHPB) system. The influences of strain rate, temperature, and water content on the energy parameters (i.e., absorption energy, reflected energy, and absorption energy rate) were systematically analyzed. Moreover, the energy dissipation characteristics of frozen sandy soil under different deformation stages were studied. Test results revealed that under impact load, the proportion of reflected energy to incident energy was the largest for frozen soil materials. Both the absorption energy and reflected energy were associated with strain rate. However, compared with the water content and temperature, the sensitivities of strain rate on the absorption energy rate were not obvious. At -10°C, the average absorption energy rate decreases from 17.6% to 14.5% when the water content increases from 15% to 37.5%, with a reduction of 18%. However, it substantially decreases to 6.9% at 45% water content, with a large-scale reduction of 61% compared with that at 15% water content. The energy dissipation parameters (i.e., absorption energy, releasable elastic strain energy, and dissipation energy) were closely associated with the water content, temperature, and strain rate.

To investigate the coupling damage characteristics of rock after high-temperature treatment under impact load, dynamic uniaxial compression tests for deep sandstone specimen under laboratory conditions varying with high temperature (i.e., 25°C, 100°C, 300°C, 500°C, 700°C, and 900°C) and strain rate (i.e., 170 s-1, 205 s-1, and 240 s-1) were performed using splitting Hopkinson pressure bar (SHPB) system. Coupling damage variable of deep sandstone was deduced based on the Lemaitre equivalent strain theory. Moreover, the damage parameters of deep sandstone were systematically determined according to the test data, and the effects of high temperature and strain rate on damage growth curves were investigated. Finally, a dynamic compound damage constitutive model, which could consider the coupling damage, was established and verified to describe the dynamic mechanical characteristic of deep sandstone. Theoretical and experimental results indicated that the simulated stress-strain curves matched the test data well and the proposed coupling damage constitutive model could reflect the high temperature-induced weakening and strain rate strengthening effect.

Electrical and electronic experiment teaching is an indispensable and important part of engineering teaching. Oscilloscope is an indispensable experimental instrument in the teaching of these experiments, which is used to measure the electrical signals in the experimental process for analysis and processing. In this paper, a dual-channel virtual oscilloscope was designed based on the PC 16-bit sound card, which could correctly collect electronic signals within ±1V. Through LabVIEW graphical programming and multi-threading technology, these functions such as waveform display, channel selection control, parameter measurement and display, waveform storage and playback were realized. The innovation of this design is that it could automatically generate experimental report, simplifying the tedious operations such as drawing waveforms and filling parameters, finally quickly getting illustrated experimental report. From the test results, it can meet the requirements of daily experimental teaching, and it is of great significance to improve the quality of electrical and electronic experimental teaching.

Due to the deterioration caused by repeated freeze–thaw cycles, concrete materials in cold regions often develop cracks, which have serious effects and challenge the durability of concrete-based structures. Therefore, it is worthwhile to repair and strengthen freeze–thaw-damaged concrete to extend the service duration of the structure. In the present study, to investigate the restorative effect of surface reinforcer on freeze–thaw-deteriorated concrete specimens, the effects of the surface reinforcer type, its action duration, and the number of applications on the strength and deformation parameters of repaired specimens were systematically studied. Moreover, pore size distribution, pore structure at different depths, and the micromorphology characteristics were investigated by nuclear magnetic resonance (NMR), pore structure, and scanning electron microscope (SEM) tests to reveal the repair mechanism of different surface reinforcer types. The results indicated that the compressive strength of freeze–thaw-deteriorated concrete could be increased by up to 15.67% after the application of the surface reinforcer. Both the values of compressive strength and deformation modulus E50 increased with the increase in the action duration. In addition, the surface reinforcer could efficiently penetrate the interior of the deteriorated specimen and was able to decrease the total proportion of multi-harmful pores and harmful pores. Furthermore, the pore structure parameters could be significantly improved at a depth of 10 mm; however, the reparative effect of the surface reinforcer gradually decreased with the increase in the action depth. The surface reinforcer could efficiently promote the second hydration of cement and generate more cementitious materials to fill the microvoids, thereby improving the compactness and mechanical properties of the repaired specimens. [ABSTRACT FROM AUTHOR]