Previous research suggests that the Augmented Reality (AR) training is more effective for the novice assemblers who undergo considerable cognitive workload. However, the factor of gender, which might ...impact the above result, has not been investigated. Gender could be an additional factor that can impact over the post-training performance of novice assemblers. The performance indicator focused in this particular study is the learning curves of human subjects with two assembly treatments. The evidence of a learning curve was reflected by the assembly performance. Controlled experimentation was conducted together with the collection of qualitative information through direct observation and monitoring. Two main findings are: 1) AR helps both male and female trainees learn the assembly routine faster, and 2) AR training is more effective for both male and female assemblers than the 3D manual, whereas training with the 3D manual is more effective for male assemblers than for female assemblers.
► We investigate the impacts of gender and training over the human performance. ► Augmented Reality helps both males and females learn the assembly routine faster. ► Augmented Reality is more effective for both males and females than the 3D manual. ► Training with the 3D manual is more effective for males than females.
Constitutive model is very important in finite element simulation of Inconel 718 cutting process. However, there are few constitutive models for Inconel 718 which are suitable for the cutting ...process. In this research, firstly, dynamic behavior of Inconel 718 at high strain rate and elevated temperature of the same order as the practical cutting process was obtained using SHPB(Split Hopkinson Pressure Bar) test. In the tests, the strain rate was 5000–11000s−1, and the temperature was 500–800°C. Secondly, thermal and strain rate effect were discussed. Strain rate softening effect was found at high strain rate and discussed, and it was temperature dependent. Finally, a modified Johnson–Cook model was established.
Oral administration is the most preferred route for drug administration in clinic. However, due to unsatisfactory physicochemical properties of drugs and various physiological barriers, the oral ...bioavailability of most poorly water-soluble and macromolecules drugs is low and the therapeutic effect is unsatisfactory. Ionic liquids (ILs), molten salts with unique properties, show amazing potential for oral delivery. In addition to being able to form active pharmaceutical ingredients based ILs (API-ILs) to overcome drug solubility and polymorphism issues, ILs have also been used to enhance the solubility of poorly soluble drugs, enhance drug stability in the gastrointestinal environment, improve drug permeability in intestinal mucus, and facilitate drug penetration across the intestinal epithelial barrier. Furthermore, ILs were attempted as formulation components to develop novel oral drug delivery systems. This review focus on the application progress of ILs in oral drug delivery and the mechanisms. The challenges and perspectives of the development of ILs-based oral delivery systems are also discussed.
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This article reviews the latest advances of ionic liquids for oral drug delivery, focusing on the application and related mechanisms of ionic liquids in improving the drug physicochemical properties and enhancing drug delivery across physiological barriers.
In the present work, we constructed nanoscale graphene oxide (NGO) as a drug nanocarrier to improve the process of tumor-targeted drug releases, promote cellular uptake and accumulation of ...chemotherapy drugs in tumor tissues, and reduce the toxic effects of chemotherapy drugs on normal cells. Hence, great stability was obtained in the biological solution. Moreover, we designed an effective nanoparticle system for the doxorubicin (DOX) delivery targeting the oral squamous cell carcinoma (OSCC) by mediating the HN-1 (TSPLNIHNGQKL) through hydrogen and π-π bonds. DOX@NGO-PEG-HN-1 showed significantly higher cellular uptakes and cytotoxicity in OSCC cells (CAL-27 and SCC-25), compared to free DOX. Moreover, HN-1 showed considerable tumor-targeting and competition inhibition phenomenon. As we expected, the nanocarrier showed pH-responsive drug release. In total, our study represented a good technique to construct OSCC-targeted delivery of nanoparticles and improve the anticancer medicines' efficiency.
To explore the feasibility of using ultra-high performance concrete (UHPC) to strengthen reinforced concrete (RC) beams in torsion, pure torsion tests on 9 specimens have been conducted in this ...study, including one RC beam without strengthening (referred as control beam) and 8 UHPC-strengthened beams. The variables considered for investigation included the wrapping form of UHPC layer, thickness of UHPC layer, shape of steel fibers added in UHPC layer, UHPC-RC interfacial treatment, and reinforcement ratio of UHPC layer. The overall torsional behavior, torque–twist curves, torque-principal strain curves, cracking pattern and UHPC-RC interfacial slippage for all specimens were obtained based on the torsion tests. Results show that the cracking and ultimate torsional moments of all strengthened beams were higher than those of the control beam, with maximum increases of 488.5% and 593.2%, respectively. When the RC beam cannot be fully wrapped, which is the preferred strengthening scheme, 3-sided wrapping form is also an acceptable choice, but the 2-sided strengthening scheme should be avoided. The determination of the thickness of UHPC layer should comprehensively consider the strengthening effect, cost for strengthening and requirements for RC beam's dimensions after strengthening. RC beam surfaces should be fully roughened before casting UHPC to ensure that the UHPC layers and the RC beam persistently act together as a whole to resist torsional loads. The UHPC layers are recommended to be equipped with steel bars, which could substantially improve the torsional capacity and ductility of the strengthened beam on the premise of limited increase in the cost. Finally, the effectiveness of torsional strengthening using UHPC was compared with that using fiber reinforced polymer (FRP) in terms of increase in cross-sectional area, increases in cracking and ultimate torsional moments, increase in torsional stiffness, failure mode and long-term performance.
Under the noncascade structure, a permanent-magnet synchronous motor (PMSM) regulates the speed and current in one loop. On the one hand, fast dynamic performance requires large transient current to ...provide a high torque. On the other hand, unlike a cascade control, the q-axis current is no longer governed by a reference current signal. In such a system, the nominal controllers cannot guarantee that the q-axis current is within the required range. But an excessively large transient current may threaten the circuit safety. To solve the overcurrent protection problem, the ordinary solution is to choose conservative control parameters, but the dynamic performance inevitably suffers a certain degree of loss. In order to improve this drawback, a simple and effective control scheme is introduced with a current-constrained technique. By constructing a special nonlinear gain, the punishment mechanism for the q-axis current is established in the control action directly. The proposed control approach does not impose limitations on the initial state. Moreover, it has good robustness to load torque uncertainty and undergoes rigorous theoretical analysis. Besides, the proposed current-constrained controller has a very concise structure. It yields a higher reliability of the PMSM control system. Comparative simulation and experimental results between the classic PID and the current-constrained controller on the PMSM servo system verify the feasibility of the presented control scheme.
Augmented reality (AR), a state-of-the-art technology for superimposing information onto the real world, has recently started to affect our daily lives. AR applications are becoming mature and ...versatile. This paper discusses trends in AR applications for architecture, engineering, construction, and facility management (AEC/FM). This paper specifically focuses on four technologies—localization, natural user interface (NUI), cloud computing, and mobile devices—which have the potential to influence the development of AR applications. Advances in localization technology will enable the deployment of AR in a complex environment. An NUI provides more convenient and intuitive user experiences, which can increase the usability of AR. Cloud computing environments allow users with internet access to ubiquitously retrieve information from almost anywhere. Hence, cloud computing increases the freedom of using AR in AEC/FM applications. Another factor that will lead to the wider usage of AR is that mobile devices are becoming smaller, more powerful, and less expensive. This paper summarizes the results of 101 research efforts, and outlines the research trends and opportunities for applying AR in the fields of AEC/FM.
Two single-entry gateroad systems employing a yield pillar for bump control in a Chinese coal mine were introduced. The overburden depth of the longwall panels was approximately 390 m. When the ...width/height (W/H) ratio of the yield pillar was 2.67, coal bumps in the tailgate occurred in front of the longwall retreating face. However, in another panel, the coal bump was eliminated because the W/H ratio was reduced to 1.67. Under this condition, instrumentation results indicated that the roof-to-floor and rib-to-rib convergences reached 1,050 and 790 mm, respectively, during longwall retreat. The numerical model was used to back-analyze the two cases of yield pillar application in the hope to find the principle for yield pillar design. In order to improve the reliability of the numerical model, the strain-hardening gob and strain-softening pillar materials were meticulously calibrated, and the coal/rock interface strength was determined by laboratory direct shear tests. The results of the validated model indicate that if the W/H ratio of the yield pillar equals 1.67, the peak vertical stress in the panel rib (37.7 MPa) is much larger than that in the yield pillar (21.1 MPa); however, the peak vertical stress in the panel rib (30.87 MPa) is smaller than that in the yield pillar (36 MPa) when the W/H ratio of yield pillar is 2.67. These findings may be helpful to the design of yield pillars for bump control.
For many decades, safety has been a challenge in the construction sector. Despite extensive efforts to improve overall safety, the sector’s casualty rate still remains high. In practice, dynamic and ...complex construction processes may lead to on-site risks and safety plans being overlooked, likely leading to a variety of safety accidents. Nowadays, under the guidance of the digital twins (DT) concept, the advent of state-of-the-art sensing and visualisation technologies has offered the possibility to improve construction health and safety in the workplace. To understand the research advances of these technologies, identify their gaps and challenges, and propose solutions to further advance the industry’s safety, we conducted and report a thorough review on the state-of-the-art technological studies, and elaborate upon the key findings in detail. For instance, despite DT being proven to be effective in improving construction workforce safety, the construction industry has yet to fully exploit and streamline these innovations in practice. Overall, this review provides insights into technological clustering, improvement strategies, as well as workforce safety, which can benefit from formulating effective digital technology paradigms.
Dynamic stability is significantly important for flying quality evaluation and control system design of the advanced aircraft, and it should be considered in the initial aerodynamic design process. ...However, most of the conventional aerodynamic optimizations only focus on static performances and the dynamic motion has never been included. In this study, a new optimization method considering both dynamic stability and general lift-to-drag ratio performance has been developed. First, the longitudinal combined dynamic derivative based on the small amplitude oscillation method is calculated. Then, combined with the PSO (particle swarm optimization) algorithm, a dynamic stability derivative that must not be decreased is added to the constraints of optimization and the lift-drag ratio is chosen as the optimization objective. Finally, a new aerodynamic optimization method can be built. We take NACA0012 as an example to validate this method. The results show that the dynamic derivative calculation method is effective and conventional optimization design can significantly improve the lift-drag ratio. However, the dynamic stability is enormously changed at the same time. By contrast, the new optimization method can improve the lift-drag performance while maintaining the dynamic stability.
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