Influence of Macrotexture and Microtexture on the Skid Resistance of Aggregates

This article intends to study the influence of macrotexture and microtexture on the skid resistance of four types of aggregates. For this purpose, fractal dimension (D), root mean square height (Rq), and Polished Stone Value (PSV) were tested. The Pearson correlation coefficients between PSV and D or Rq in the interval of different polishing cycles were calculated and analyzed with correlation analysis. The relationships between PSV and Rq were also established. The results showed that the PSV development was approximately divided into 3 stages including accelerated attenuation stage, decelerated attenuation stage, and stabilization stage. There is a critical point of the entire polishing cycles. When the number of the polishing cycles exceeds this critical point, microtexture replaces macrotexture to play a major role in the skid resistance of aggregates. In the accelerated attenuation stage, macrotexture plays a major role in the skid resistance of aggregates. In the decelerated attenuation stage and stabilization stage, microtexture gradually plays a major role in the skid resistance of aggregates. Because of roughest microtexture in the stabilization stage, bauxite can provide the highest levels of skid resistance for high friction surface treatment over the long-term period

The Prevalence and Correlated Factors of Occupational Stress, Cumulative Fatigue, and Musculoskeletal Disorders among Information Technology Workers: A Cross-Sectional Study in Chongqing, China

Occupational stress, cumulative fatigue, and work-related musculoskeletal disorders (WMSDs) are major concerns in the field of occupational health. Previous studies on occupational health focused on key industries, such as medical care, while there were few related studies on Information Technology (IT) industry. Our study explored the factors influencing occupational stress, cumulative fatigue, and musculoskeletal disorders in the IT industry. We collected 1363 IT workers’ valid questionnaires, of which 73.1% of participants were technicians in Chongqing, 2021. The core occupational stress scale (COSS), self-diagnosis checklist for the assessment of workers’ accumulated fatigue and Chinese musculoskeletal disorders questionnaire were used to measure the occupational stress, cumulative fatigue, and musculoskeletal disorders of the respondents. Logistic regressions were used to explore the correlated factors affecting these indicators. The results showed that the prevalence of occupational stress, cumulative fatigue, and musculoskeletal disorders was 50.4%, 47%, and 72.3%, respectively. Working in the current position for 3–10 years was a common increased risk for all three indicators. Insomnia was associated with an increased risk of cumulative fatigue (Odds Ratio, OR = 2.156, p p p < 0.001). According to our findings, occupational factors, such as long working years, overtime work, and personal lifestyle, are highly related to the occurrence of occupational stress, cumulative fatigue, and musculoskeletal disorders for IT industry workers. More attention should be paid to women and those with long working hours in the IT industry

Low-dimensional van der Waals materials for linear-polarization-sensitive photodetection: materials, polarizing strategies and applications

Detecting light from a wealth of physical degrees of freedom (e.g. wavelength, intensity, polarization state, phase, etc) enables the acquirement of more comprehensive information. In the past two decades, low-dimensional van der Waals materials (vdWMs) have established themselves as transformative building blocks toward lensless polarization optoelectronics, which is highly beneficial for optoelectronic system miniaturization. This review provides a comprehensive overview on the recent development of low-dimensional vdWM polarized photodetectors. To begin with, the exploitation of pristine 1D/2D vdWMs with immanent in-plane anisotropy and related heterostructures for filterless polarization-sensitive photodetectors is introduced. Then, we have systematically epitomized the various strategies to induce polarization photosensitivity and enhance the degree of anisotropy for low-dimensional vdWM photodetectors, including quantum tailoring, construction of core–shell structures, rolling engineering, ferroelectric regulation, strain engineering, etc, with emphasis on the fundamental physical principles. Following that, the ingenious optoelectronic applications based on the low-dimensional vdWM polarized photodetectors, including multiplexing optical communications and enhanced-contrast imaging, have been presented. In the end, the current challenges along with the future prospects of this burgeoning research field have been underscored. On the whole, the review depicts a fascinating landscape for the next-generation high-integration multifunctional optoelectronic systems

Research progress in nitrogen-doped electrically conductive silicon carbide ceramics

The electrically conductive silicon carbide (SiC) ceramics that can be machined by electrical discharge machining, can not only overcome the highlight shortcomings of traditional high resistivity-grade SiC ceramics in machinability, but also maintain its other excellent properties. It has outstanding advantages to replace traditional high resistivity-grade SiC ceramics in the field of structural ceramics. In this paper, the nitrogen doping principle of electrically conductive SiC ceramics was illustrated, and then the powder sintering methods, sintering additives, thermoelectric and mechanical properties were summarized. Meanwhile, in order to provide guidance for the control of electrical properties, the electrical properties-related factors were discussed. In the end, the main challenges of nitrogen-doped electrically conductive SiC ceramics were pointed out, and the future interests were suggested to focus on the development of new sintering technology and additive, as well as clarifying the control mechanism of electrical properties, thereby establishing the technical foundation for fabrication of high-performance conductive SiC ceramics with controllable electrical resistivity

High Performance and Self-Humidifying of Novel Cross-Linked and Nanocomposite Proton Exchange Membranes Based on Sulfonated Polysulfone

The introduction of inorganic additive or nanoparticles into fluorine-free proton exchange membranes (PEMs) can improve proton conductivity and have considerable effects on the performance of polymer electrolyte membrane fuel cells. Based on the sol&ndash;gel method and in situ polycondensation, novel cross-linked PEM and nanocomposite PEMs based on a sulfonated polysulfone (SPSU) matrix were prepared by introducing graphene oxide (GO) polymeric brushes and incorporating Pt-TiO2 nanoparticles into an SPSU matrix, respectively. The results showed that the incorporation of Pt-TiO2 nanoparticles could obviously enhance self-humidifying and thermal stability. In addition, GO polymer brushes fixed on polymeric PEM by forming a cross-linked network structure could not only solve the leakage of inorganic additives during use and compatibility problem with organic polymers, but also significantly improve proton conductivity and reduce methanol permeability of the nanocomposite PEM. Proton conductivity, water uptake and methanol permeability of the nanocomposite PEM can be up to 6.93 mS cm&minus;1, 46.58% and be as low as 1.4157 &times; 10&minus;6 cm2 s&minus;1, respectively, which represent increases of about 70%, about 22% and a decrease of about 40%, respectively, compared with that of primary SPSU. Therefore, the synergic action of the covalent cross-linking, GO polymer brush and nanoparticles can significantly and simultaneously improve the overall performance of the composite PEM

Yield and nitrogen uptake of sole and intercropped maize and peanut in response to N fertilizer input

Chinese agriculture needs to become less dependent on fertilizer inputs to enhance sustainability. Cereal/legume intercropping is a potential pathway to lower fertilizer inputs, but there is insufficient knowledge on the nitrogen (N) response in species mixtures. Here, we investigated N response in maize/peanut intercropping. Maize showed a stronger yield response to N input than peanut both in sole cropping and in intercropping, and so did sole crops relative to intercrops. Maize yield was the highest at the maximum level tested: 360 kg N/ha. Agronomic efficiency (AE) of sole maize was 7.8 kg/kg N input, averaged across five N levels (0, 90, 180, 270, and 360 kg/ha). Partial land equivalent ratios (pLERs) for maize decreased with N input, from 0.70 at zero to 0.64 at 360 kg/ha. Sole peanut showed an optimum yield response to N input, with the highest yield at 270 kg/ha and lower yield at 360 kg/ha. The average AE of sole peanut was 1.3 kg/kg. The pLER of peanut declined from 0.43 at zero to 0.32 at 360 kg/ha while the overall LER decreased from 1.13 to 0.96, indicating relative better performance of intercropping at low than at high N input. Apparent recovery (RE) for N was 27.2% for sole maize, 12.4% for sole peanut, and 7.2% for intercrops. Mean N uptake was 179 kg/ha in sole maize, 199 kg/ha in intercropping, and 264 kg/ha in sole peanut. Partial economic budgeting indicated that with the current low Chinese N fertilizer prices, gross margin is maximized with high N input in sole crops; however, for intercropping, the highest gross margin was attained at intermediate N inputs of 180 or 270 kg/ha. Fertilizer price incentives may facilitate a transition to intercropping at moderate N input in China.</p