Typical Working Research Articles

Quantifying Contributions of Different Repulsion to Film Drainage Time during the Bubble-Solid Surface Attachment and Implications for the Flotation of Fine Particles.

The flotation recovery of fine particles faces serious challenges due to the lack of kinetic energy required for supporting their radial displacement and attachment with bubbles. Generally, the hydrodynamic resistance and repulsive disjoining pressure successively inhibit the liquid outflow intervening between the bubble and solid surfaces. To quantitatively characterize the influence of the main repulsion on film thinning time, experiments have been designed in three different aqueous systems. Bubble surface mobility closely associated with hydrodynamic resistance was determined by the rising bubble technique, and the DLVO theory was employed to confirm the evolution of electrostatic repulsion. The film drainage process was then measured based on the high-speed microscopic interferometry. Furthermore, the influence of the main repulsion on bubble-solid surface interactions was examined by flotation recovery. Results show that the earlier buildup of hydrodynamic force ran through the whole film thinning process, and under immobile conditions, the central region gradually became dominant in film thinning due to the very limited fluid flow at the thinnest rim position. Therefore, to achieve the identical film thickness (∼100 nm), the large hydrodynamic resistance could prolong the film thinning time by about 1 order of magnitude, compared with that induced by electrostatic repulsion, which accounts for the increased flotation recovery by 10% using mobile bubbles. This study not only enhances the understanding of how typical repulsive forces work in film drainage dynamics but also opens up an avenue for enhancing flotation and avoiding wasting resources by modulating bubble surface mobility and thus micro/nanoscale fluid flow.

Mining Trajectory Planning of Unmanned Excavator Based on Machine Learning

Trajectory planning plays a crucial role in achieving unmanned excavator operations. The quality of trajectory planning results heavily relies on the level of rules extracted from objects such as scenes and optimization objectives, using traditional theoretical methods. To address this issue, this study focuses on professional operators and employs machine learning methods for job trajectory planning, thereby obtaining planned trajectories which exhibit excellent characteristics similar to those of professional operators. Under typical working conditions, data collection and analysis are conducted on the job trajectories of professional operators, with key points being extracted. Machine learning is then utilized to train models under different parameters in order to obtain the optimal model. To ensure sufficient samples for machine learning training, the bootstrap method is employed to adequately expand the sample size. Compared with the traditional spline curve method, the trajectories generated by machine learning models reduce the maximum speeds of excavator boom arm, dipper stick, bucket, and swing joint by 8.64 deg/s, 10.24 deg/s, 18.33 deg/s, and 1.6 deg/s, respectively; moreover, the error does not exceed 2.99 deg when compared with curves drawn by professional operators; and, finally, the trajectories generated by this model are continuously differentiable without position or velocity discontinuities, and their overall performance surpasses that of those generated by the traditional spline curve method. This paper proposes a trajectory generation method that combines excellent operators with machine learning and establishes a machine learning-based trajectory-planning model that eliminates the need for manually establishing complex rules. It is applicable to motion path planning in various working conditions of unmanned excavators.

Efficiency of working coveralls and chemical resistant gloves in reducing operator exposure to pesticides

Personal Protective Equipment (PPE) is used to reduce exposure when working with chemicals. For pesticides, exposure scenarios comprise mixing and loading (M&L) and application. The exposure prediction model recommended by European regulatory agencies for operator risk assessments—the Agricultural Operator Exposure Model (AOEM) – is based on 48 operator exposure studies involving over 500 professional operators from 10 European countries in typical working situations to assess exposure under realistic field conditions. We used the AOEM data to assess the efficiency of exposure reduction resulting from wearing chemical-resistant nitrile gloves and non-certified working coveralls during M&L (tank and backpack sprayer), applications using groundboom and airblast spraying, and outdoor and indoor (greenhouse) applications using handheld sprayers. All studies indicated consistent and high exposure reduction > 90% for gloves and non-certified coveralls across all investigated scenarios. Exceptions were almost exclusively observed when an operator incorrectly used the PPE. The mean exposure reduction from all operators, including those that used PPE incorrectly, was 95.0% for gloves and 96.4% for polyester/cotton working coveralls during M&L, and 91.1% for gloves and 94.9% for non-certified coveralls during all application scenarios. This analysis confirms the essential role of PPE and non-certified working coveralls in reducing operator exposure to pesticides. Outliers indicate that operators need to be properly trained and adhere to label instructions to apply pesticides according to good agricultural practices.

0265 Disparities in Bed and Wake Times in the US Population Associated with Typical Work Hours

0265 Disparities in Bed and Wake Times in the US Population Associated with Typical Work Hours

Integrated combined heating, cooling and electricity system based on triple-effect free-piston Stirling configuration

Conventional combined cooling, heating, and power (CCHP) systems, involving multiple energy conversion technologies, are composed of a variety of coupled subsystems with different working principles. To solve the problems of bulky structure, operational complexity, and high initial investment cost, a novel integrated combined heating, cooling, and electricity system based on the same energy conversion technology with a triple-effect free-piston Stirling configuration was proposed. Compared with the traditional system, the novel integrated system can cool, heat, and generate power using one machine without introducing additional devices. Some verification experiments were tested on a built experimental platform to validate the feasibility of the concept of this configuration. The result shows that the system was able to obtain the highest values of COPc, COPh, and the output performance coefficient of 0.26, 1.28, and 1.54, respectively, which can save 39 % of energy consumption compared with traditional independent energy-supplying systems when providing the same cooling and heating capacity and electricity under typical working conditions. It is expected that the reported result can facilitate a practical application in decentralized CCHP systems.

Research on Energy Management Strategy for Series Hybrid Tractor under Typical Operating Conditions Based on Dynamic Programming

In response to the issues of hybrid tractors’ energy management strategies, such as reliance on experience, difficulty in achieving optimal control, and incomplete analysis of typical operating conditions of tractors, an energy management strategy based on dynamic programming is proposed in combination with various typical operating conditions of tractors. This is aimed at providing a reference for the modeling and energy management strategies of series hybrid tractors. Taking the series hybrid tractor as the research object, the tractor dynamics models under three typical working conditions of plowing, rotary tillage, and transportation were established. With the minimum total fuel consumption of the tractor as the optimization target, the engine power as the control variable, and the state of charge of the power battery as the state variable, an energy management strategy based on a dynamic programming algorithm was established and simulation experiments were conducted. The simulation results show that, compared with the power-following energy management strategy, the energy management strategy based on the dynamic programming algorithm can reasonably control the operating state of the engine. Under the three typical working conditions of plowing, rotary tillage, and transportation, the battery SOC consumption increased by approximately 8.37%, 7.24%, and 0.77%, respectively, while the total fuel consumption decreased by approximately 25.28%, 21.54%, and 13.24%, respectively.

Parameter study and identification of DEM modeling for varied sand moisture content based on bulldozing experiment

The discrete element method (DEM) has been widely used to simulate varied sand particles interacting with earthmoving machines. However, past research using DEM barely addressed accurate verification and validation for different sand moisture content. Therefore, the main purpose of this paper is to reveal the range of key parameters of an adhesive force model used in the DEM simulation corresponding to the specific sand moisture content. We considered the bulldozing phenomenon to be typical earthmoving work and performed the bulldozing experiments under different sand moisture levels to investigate the bulldozing force variations. Subsequently, the DEM simulation with an adhesive force model calculated the bulldozing force corresponding to the experimental results. The values for two adhesive parameters, i.e., a scaling magnitude and the maximum adhesive distance between particles, were adjusted such that the maximum bulldozing force calculated in the DEM coincides with that of the experiments under different moisture contents. The experimental verification of the DEM revealed the relationship curves between these two key parameters corresponding to the different moisture content. The relationship obtained in this paper implies that the DEM simulation carefully adjusting the adhesive force parameters can reproduce machine interaction on moist sand environments accurately.

Adaptive Terminal Sliding Mode Trajectory Tracking Control for Autonomous Vehicles Considering Completely Unknown Parameters and Unknown Perturbation Conditions

In the actual implementation of autonomous vehicle controller and related applications, it is difficult to obtain all the actual parameters of the vehicle. Considering factors such as uneven pavement and different pavement conditions, it is difficult to accurately establish the vehicle dynamic system model. Based on the non-singular terminal sliding mode and adaptive control theory, this paper establishes a trajectory tracking control strategy for an autonomous vehicle with unknown parameters and unknown disturbances. Firstly, the complex trajectory tracking problem is decoupled from the position and heading angle tracking problem, and the preview error equation is established. Secondly, a non-singular terminal sliding mode (NTSM) controller is established to stabilize the trajectory tracking error to the origin in a finite time, and adaptive laws are proposed to estimate the unknown vehicle parameters to adapt to environmental changes. Through the CarSim–Matlab platform, typical working conditions are implemented to verify the proposed controller. Our experimental outcomes affirm that the NTSM controller effectively guarantees the autonomous vehicle’s accurate following of the reference path, ensuring smooth control inputs throughout the entire process.

Self-employed and stressed out? The impact of stress and stress management on entrepreneurs' mental health and performance.

Entrepreneurs play a central role in economic and social stability, yet the start-up rate in Germany has declined in recent years, possibly due to the stress associated with entrepreneurial endeavors. Stressors such as financial uncertainty and time pressure are prevalent among entrepreneurs and negatively affect their psychological well-being. However, research on stress management strategies among self-employed individuals remains limited. This pilot study conducted a quantitative analysis with 117 self-employed participants in Germany. The study focused on typical entrepreneurial work demands and selected stress coping mechanisms. The analysis revealed a significant correlation between quantitative demands and mental exhaustion. Furthermore, a high positive correlation between presenteeism and workload suggests that presenteeism may partially explain the variance in workload. These findings underscore how high job demands can lead to self-endangering behaviors that are detrimental to mental health. Although no significant moderating effect of proactive coping on the relationship between job demands and mental exhaustion was observed, significant negative correlations between proactive coping and both job demands and mental exhaustion suggest a potential protective role of proactive coping against work-related stress. This study highlights the importance of understanding stress coping strategies among self-employed individuals and their impact on entrepreneurial success and mental well-being. Further research in this area is warranted to develop effective interventions to support the well-being and productivity of self-employed individuals in Germany.

Study on scuffing failure of gas turbine ball bearing based on 3D mixed lubrication and dynamics

Ship gas turbine bearings are subjected to heavy loads and intricate interface micromorphologies, predominantly operate in a mixed lubrication regime. Excessive asperity relative sliding can cause transient high-temperature spikes at contact points, leading to scuffing failures. Dynamic parameters such as bearing friction and clearance, along with vibrations causing fluctuating velocities and loads, further influence the lubrication condition that, in its turn, can increase the risk of scuffing. This study focuses on oil-lubricated gas turbine bearings, accounting for their typical transient working conditions and real surface roughness. The coupling characteristics of ball bearing dynamics, lubrication, and flash temperature are explored. Findings indicate that the most severe contact conditions occur at azimuth angles of 0° and 360°. The risk of ball Scuffing failure exceeds that of the inner raceway. As axial load increases under the azimuth angle of 360°, the area with zero film thickness is increasing, elevating the chances of asperity contact, friction coefficient, and interface temperature, which is detrimental to lubrication. To mitigate pitting and scuffing failures, it's recommended to maintain the bearing's maximum hertz pressure below 1.21 GPa.

Beyond academic development as institutional practice: advancing community-led approaches

ABSTRACT We introduce the special issue entitled ‘Beyond academic development as institutional practice: advancing community-led approaches’ and offer critical commentary that advances the concept and practice of academic community development. Through repeated readings of the 10 articles from diverse contexts included in this issue, we draw out four main themes highlighting why and how academic communities beyond single institutions support academic development. First, we revise the initial conceptual framework of ‘academic community development (ACD)’, which focused the call for papers, presenting six dimensions rather than the previous three continua. Then, we consider the degree of ‘institutionalisation’ of this range of initiatives. From that analysis, we derive a typology of ACD initiatives. We then consider a) what common interests have been served by these communities, and whose they are; b) the focus of these communities in relation to the revised conceptual framework; and c) the essential ingredients for success. We emphasise that communities leverage assets in ways that traditional needs-based academic development often does not. We conclude with implications for typical academic development work.

Failure mechanism and control method of cement sheath sealing integrity under alternating thermal-stress coupling in geothermal wells

In geothermal wells, exposure to extreme conditions of alternating temperature-pressure coupling (T-P-C) may lead to repeated expansion and contraction of the casing and cement sheath. This can degrade the cement sheath sealing integrity, resulting in continuous annular pressure. Consequently, an elastic-plastic mechanical model of the casing-cement sheath-formation (C–S–F) system under T-P-C was established based on thermodynamic theory and elastic-plastic theory with consideration of additional heating strain and thermal load, and it is solved by global search in MATLAB. The elastic-plastic mechanical behavior and development of interfacial contact stress are investigated under four typical working conditions. The failure mechanisms include interfacial debonding and micro-annulus formation between the casing and cement sheath under strong alternating temperatures (SAT). Cycling of temperature and accumulated plastic strain caused by the cement sheath entering plasticity are the major causes of interfacial stress inversion, which leads to interfacial debonding during temperature unloading. The influences of the mechanical and thermodynamic parameters of the cement sheath on its sealing integrity are analyzed. Based on this, an integrity control method is proposed, which comprises a cement slurry system and considers cement mechanical and thermodynamic parameters and environmental conditions. The results provide an important reference for the optimal design of cement slurry systems and for preventing cement sheath integrity failures due to SAT.

Innovation and evaluation of vocational pharmaceutical education system under the 1 + X certificate system in China

Background and objectivesThe 1 + X certificate system, introduced in China in 2019, integrates academic credentials with vocational skill certificates to meet the heightened demand for skilled talents in the growing economy. This study aims to innovate and evaluate the vocational pharmaceutical education system under the 1 + X certificate framework, specifically addressing the gap between theoretical education and workplace requirements. Materials and methodsA retrospective observational approach analyzed 490 pharmacy students over two academic years. The 2021 cohort underwent 1 + X integrated education, while the 2020 cohort followed conventional education. We collaborated closely with industry partners to identify and compile typical job competencies, formulating work projects aligned with industry demands. Combining the skill level standards and assessment content of “1+X Pharmaceutical Purchasing and Sales” and “1+X Pharmaceutical Preparation”, we revised the course standards, incorporating typical work projects into the 2021 pharmacy professional teaching curriculum. This constituted the fundamental content of the 1 + X education reform. Statistical analysis compared course scores and 1 + X certificate examination performance. ResultsThe 2021 cohort, under the 1 + X educational model, demonstrated higher average scores in pharmacy courses, with significant improvements in pharmacology (1 + X vs. Traditional education: 58.40 ± 14.20 vs. 53.44 ± 14.67), clinical pharmacotherapy (72.74 ± 10.28 vs. 63.15 ± 11.03), and pharmaceutical distribution and marketing (79.34 ± 10.96 vs. 67.50 ± 15.82). 1 + X certificate pass rates and satisfaction with the model were also higher than the 2020 cohort. ConclusionThe 1 + X certificate system is useful for developing talent in Chinese vocational education, effectively integrating assessments with industry standards. Future research should aim at evaluating long-term outcomes and improving quantitative skills assessments for enhanced effectiveness.

Research on adaptive shooting algorithm for unmanned aerial vehicles under typical operating conditions of overhead transmission lines

We consider typical environmental conditions, such as different shooting backgrounds, lighting, and shooting distances, and study adaptive shooting algorithms for unmanned aerial vehicle (UAV) on-site environments under typical working conditions to achieve high-quality acquisition of UAV inspection images and reduce the technical difficulty of artificial intelligence recognition of inspection images. Based on the collected high-quality images and the characteristics of unmanned aerial vehicle inspection images, a deep learning technology framework is adopted to study the intelligent identification method of hidden dangers in transmission line equipment and channel environment, achieving the intelligent recognition of pin level fine particle defects.

Analysis of Dynamic Wear Characteristics of Joint Contact Friction Pair of Excavators Working Device

The working device of an excavator in construction machinery is prone to damage and wear under ordinary working conditions. Based on a model of an excavator under typical working conditions, the dynamic load-bearing situation of the three main joint friction subsets of the working device is simulated by using the virtual prototype technology; the location of the functional device with high stress is identified based on finite element analysis, and the correctness of the simulation results is verified by designing strain gauges. Based on this, the dynamic contact stress variation law of the contact surface of the end-face friction subsets was explored, and the end-face wear depth was calculated by combining Archard wear theory and finite element wear simulation technology; the specimens were worn on the end-face wear tester, and the surface wear was observed under the scanning electron microscope to summarize the wear mechanism and analyze the element content changes of the worn surface. The results show that the three main joints of the working device produce large dynamic fluctuations and are prone to wear, and the destructive degree is more prominent; the wear process is accompanied by higher temperatures, fatigue wear, and abrasive wear on the wear surface, and the wear depth value of the right end face is significantly larger than that of the left end face. This method has a significant reference value for reliability analysis and optimization improvement when using construction machinery’s main joint friction pairs.

Enhancing the International Communication Effectiveness of "The Spirit of Lei Feng" in Anshan: A Study of the External Propaganda Strategy of "Guo Mingyi's Story" from the Perspective of Eco-translatology

As an important part of the fine traditional culture of the Chinese nation, the "spirit of Lei Feng" has always been an important content of domestic propaganda. With the continuous deepening of globalization, how to effectively spread this cultural phenomenon with Chinese characteristics to the international community has become an urgent problem to be solved. The Story of Guo Mingyi is a typical work that demonstrates the "spirit of Lei Feng". By applying the theoretical framework of ecological translation to its external publicity strategy research, exploring its translation strategies in terms of language, culture, and communication, and proposing targeted suggestions and measures, we can not only enrich and develop the theoretical system of ecological translation, but also enhance the international communication effectiveness of the "spirit of Lei Feng" in Anshan, promote the international dissemination of Chinese culture, and provide useful reference and enlightenment for the international dissemination of other cultural phenomena.

Thermoacoustic refrigeration with compressible liquid as working fluid

The classical thermoacoustic refrigeration adopts gases with ideal-gas properties as working fluids. Herein, the thermoacoustic refrigeration using a compressible liquid as the working fluid is investigated for the first time. Two models are utilized parallelly: a highly-simplified short refrigerator model and a far-more realistic full-scale thermoacoustic refrigerator model. The results from the short refrigerator model show that, ideally, the coefficient of performance can reach above 70% of the Carnot limit. In the full-scale system discussion, the coefficient of performance of the system can reach as high as 4.1 in a typical working condition for air conditioning (pumping heat from 285 K to 310 K), with respect to 36% of the Carnot limit. When pumping heat from 332 K to 357 K, the coefficient of performance can reach 44% of the Carnot limit. These results indicate that the efficiency of the thermoacoustic refrigeration with a compressible liquid as the working fluid is potentially high, but with a much smaller displacement amplitude of the fluid. As a result, both the acoustic source (the linear motor, for instance) and the heat exchanger can be much more compact, so that the mass and the volume of the system can be greatly reduced, as well as the cost.

Abstract P482: Associations Between Determinates of Food Choice and Healthy Eating Index-2015 in Adults: An NHANES 2017 - 2018 Analysis

Introduction: Previous work in nationally representative US samples has focused on associations between single determinants of food choice and diet quality assessed by the Health Eating Index-2015 (HEI-2015). Limited research has examined the relationship between multiple domains of food choice and diet quality. A greater understanding of the association between individual-level determinants of food choice and diet quality may inform the development of interventions to improve diet quality. Aim: The aim was to examine the association between potentially modifiable factors known to affect individual-level food choice and HEI-2015. Methods: This cross-sectional analysis included adult participants in NHANES 2017 - 2018. Determinates of individual-level food choice were based on a previously proposed framework. Variables assessed in NHANES were mapped to the following four domains: 1) food-external factors (use of nutrition labels, hours worked weekly, typical work schedule); 2) personal-state factors (health status, consumption of food away from home); 3) cognitive factors (perceived diet quality, knowledge of MyPlate); 4) society-related features (monthly grocery expenditures, food security status, income to poverty ratio). Univariate regression assessed the relationship between food choice determinates and HEI-2015 score. Statistically significant variables were entered into multivariate regression models predicting HEI-2015 score. Significant variables from the final model were used in multivariate regression models predicting adequacy and moderation component sub scores of HEI-2015. All models were adjusted for non-modifiable determinates of food choice, including age, sex, race, BMI, education, and relationship status. All analyses were survey weighted. Results: The weighted mean HEI-2015 score for the sample (N=1467) was 51.69 points (95% CI 49.55, 53.84; weighted n=95.6 million). In the final model, perceived diet quality, food away from home, and use of nutrition labels were significant predictors of HEI-2015 (R 2 adj =0.25, p<0.001). Those with excellent/very good perceived diet quality had a 4.88-pt higher HEI-2015 score than those with fair/poor perceived diet quality (p<0.001). Consuming food away from home ≥5 times per week resulted in a 5.92-pt lower HEI-2015 score than 0 times per week (p=0.02). Always/most of the time using nutrition labels was associated with a 7.85-pt higher HEI-2015 score compared to rarely/never using labels (p<0.001). Variables accounted for a higher proportion of variance in adequacy score (R 2 adj =0.10, p<.001) than moderation score (R 2 adj =0.24, p<.001). Conclusion: Food-external, personal-state, cognitive, and socio-cultural factors are associated with diet quality. Future research should consider multiple individual-level food-choice determinates when developing interventions to improve diet quality.

Assessment of Brief Online Approaches for Teaching Neuroscience in Psychiatry.

The goal of this study was to assess an online collection of brief educational resources (videos, case studies, articles) for teaching a broad range of concepts relating to neuroscience in psychiatry. A national sample of 52 psychiatrists enrolled in the study. Forty (77%) completed an assessment before and after having access to the educational resources for 4weeks. Pre- and post-assessments were compared using paired t-tests. Fifteen participants were randomly selected to participate in a semi-structured interview. The mean knowledge score increased on a multiple-choice quiz from 46.9 to 86.4% (p < .01). Based on a 5-point Likert rating, participants reported significant gains in self-confidence in their ability to integrate a neuroscience perspective into their clinical work (p = .03) and to discuss neuroscience with their patients (p = .008). Participants rated the extent that they applied neuroscience concepts (such as neurotransmitters, genetics, epigenetics, synaptic plasticity, and neural circuitry) to their overall case formulation and treatment plan over the past typical work week and how often they discussed these elements with patients. Significant gains were noted across all elements (p ≤ .001). Overall satisfaction with the resources were high: participants agreed that the content was useful and relevant (100%) and the teaching resources were engaging (95%). On semi-structured interviews, participants appreciated the mixed teaching approaches and the brief format. Many commented on how the resources impacted their clinical practice. Brief online teaching resources may be an effective approach for enhancing neuroscience education among psychiatrists and may help facilitate the integration of neuroscience into clinical practice.

Construction of medium-entropy alloys coupled Z-Scheme heterojunction and its enhanced photocatalytic performance by regulating mechanism of LSPR effect

Optimizing the local surface plasmon resonance (LSPR) effect of non-noble metals through alloying has been crucial for improving its practical application in the field of photocatalysis. Rare studies capture the detail that the change in the electronic structure of metal elements caused by alloying affects plasma carrier concentration and the local surface plasmon resonance effect. Herein, NiCuCoFe medium-entropy alloys (MEAs) nanoclusters were designed and used to modify the Bi3O4Br/CNNs Z-scheme heterojunction. The cocktail effect of MEAs causes the 3d-orbital hybridization of various metal elements, which promotes the release of charge carriers. The higher the carrier concentration, the stronger the LSPR effect of MEAs. In addition, the mechanism of three typical working pathways of the LSPR effect to improve the photocatalytic performance of heterojunction is discussed. And compared with those of Bi3O4Br, CNNs, and Bi3O4Br/CNNs, the rate constant of MEAs-Bi3O4Br/CNNs was 3.26, 11.16, and 3.17 times higher during the degradation of norfloxacin, respectively. This study provides a new strategy for understanding the mechanism of LSPR and the rational design of plasmonic coupling architectures for enhanced photocatalysis.