Comprehensive Advantages Research Articles

Computational Investigation of a Tibial Implant Using Topology Optimization and Finite Element Analysis

Additive manufacturing methods enable the rapid fabrication of fully functional customized objects with complex geometry and lift the limitations of traditional manufacturing techniques, such as machining. Therefore, the structural optimization of parts has concentrated increased scientific interest and more especially for topology optimization (TO) processes. In this paper, the working principles and the two approaches of the TO procedures were analyzed along with an investigation and a comparative study of a novel case study for the TO processes of a tibial implant designed for additive manufacturing (DfAM). In detail, the case study focused on the TO of a tibial implant for knee replacement surgery in order to improve the overall design and enhance its efficiency and the rehabilitation process. An initial design of a customized tibial implant was developed utilizing reserve engineering procedures with DICOM files from a CT scan machine. The mechanical performance of the designed implant was examined via finite element analyses (FEA) under realistic static loads. The TO was conducted with two distinct approaches, namely density-based and discrete-based, to compare them and lead to the best approach for biomechanical applications. The overall performance of each approach was evaluated through FEA, and its contribution to the final mass reduction was measured. Through this study, the maximum reduction in the implant’s mass was achieved by maintaining the mechanical performance at the desired levels and the best approach was pointed out. To conclude, with the discrete-based approach, a mass reduction of around 45% was achieved, almost double of the density-based approach, offering on the part physical properties which provide comprehensive advantages for biomechanical application.

Application and Analysis of New Pro-Environment and Water-Saving Composite Water Cooling System in Natural Gas Long Distance Pipeline

The traditional water cooling system of electric drive compressor in natural gas long distance pipeline uses cooling water tower, which has many problems in practical engineering: spraying water for cooling consumes a large amount of water continuously, continuous dosing and sewage discharge is needed, and winter anti-freezing measures are complex and so on. In view of the above defects of cooling water tower, this paper introduces a new type of composite water cooling system, which is completely closed, cooling without spraying water, no water consumption and discharge, daily maintenance free, its comprehensive advantages are obvious. The first composite water cooling system has been put into operation for more than 5 years, with good functions and performance, and has been widely used in electric drive compressor engineering stations.

Design of voltage stabilizing control for a hybrid microgrid with state constraints based on the switching system

With the application and development of new energy generation technology and distributed power supply system, AC-DC hybrid microgrid has the comprehensive advantages of AC microgrid and DC microgrid, and it is significant to study the voltage stability of hybrid microgrid. Based on the switching system theory, the voltage stability control of the ac-dc hybrid micro-grid in grid-connected and the off-grid operation mode are studied in this paper. Considering that the AC and DC bus voltages of the microgrid are constrained in practical engineering applications, the Backstepping controller is designed by using the barrier Lyapunov function and Backstepping method. Considering that the equivalent resistance in the system can not be accurately measured and combined with adaptive control, it is more practical for practical engineering applications.

Omnidirectional-Radiating, Vertically Polarized, Wideband, Electrically Small Filtenna

An omnidirectional, vertically polarized (VP), wideband, electrically small near-field resonant parasitic (NFRP) filtenna is presented. First, a specially-engineered tridimensional inverted-F structure is developed as the driven element to replace the feed copper pin of the shorted top-hat loaded monopole, forming a new NFRP VP antenna with a smaller size, a wider fractional bandwidth (FBW), and a radiation null in the low frequency band edge. Next, a pair of C-shaped slots are etched on the NFRP element to further expand the FBW through introducing an additional resonance, and meanwhile bring a radiation null in upper frequency band edge. The collaboration of the upper and lower radiation nulls empowers the developed antenna an excellent band-pass filtering property. Particularly, the equivalent circuit and surface current distribution are demonstrated to provide a clear insight into the mechanism of the two radiation nulls. Then, the developed inverted-F driven structure is evolved into a coupling-fed version to further improve the FBW, size and filtering performance. Finally, the developed filtenna is fabricated, installed, and measured. The measured results, which are in good agreement with the simulated values, demonstrate that, with a low profile ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.069\mathbf {\mathrm {\lambda }} _{\mathrm{ L}}$ </tex-math></inline-formula> ) and an electrically small size (ka = 0.74), the developed VP NFRP filtenna achieves a wide FBW of 32% and an enhanced peak realized gain of 6.1 dBi, exhibiting comprehensive advantages in the electric size, profile, FBW and realized gain.

Topological network design toward high‐performance vegetable oil–based elastomers

AbstractAs a kind of bio‐derived feedstock, vegetable oil (VO) shows great potential to replace petroleum‐based monomers to develop sustainable polymer materials because of its easy availability, low cost, bio‐renewable, and environmentally friendly nature. However, due to the high cross‐linking density and amorphous nature, directly cured VOs generally tend to be brittle and weak. To date, it is still difficult to adopt VOs and their derivatives as structural materials to prepare high‐performance elastomers. To address this important issue, a multi‐scale topology design strategy was proposed in this work. First, topology regulation and functionalization of VO‐based networks were realized by managing functional groups proportion during the bulk polymerization of epoxidized soybean oil with dimer fatty acids. Furthermore, a second polymer (SN) network was introduced into the VO‐based network as a protective layer via interfacial cross‐links. The generated VO‐based elastomers (VOEs) exhibit unprecedented comprehensive properties (VO content ≥70 wt.%, Tg as low as −24.4°C, toughness up to 6.8 MJ/m3). Besides, the VOEs also exhibit excellent reprocessability and self‐healing capability. Overall, this work developed a novel kind of VOEs with significant comprehensive advantages and provided important inspiration for the preparation of high‐performance elastomers through multi‐scale topology regulation.

Liquid-solid ratio during hydrothermal carbonization affects hydrochar application potential in soil: Based on characteristics comparison and economic benefit analysis

Returning straw-like agricultural waste to the field by converting it into hydrochar through hydrothermal carbonization (HTC) is an important way to realize resource utilization of waste, soil improvement, and carbon sequestration. However, the large-scale HTC is highly limited by the large water consumption and waste liquid pollution. Here, we propose strategies to optimize the liquid-solid ratio (LSR) of HTC, and comprehensively evaluate the stability, soil application potential, and economic benefits of corn stover-based hydrochar under different LSRs. The results showed that the total amount of dissolved organic carbon of hydrochars increased by 55.0% as LSR reducing from 10:1 to 2:1, while the element content, thermal stability, carbon fixation potential, specific surface area, pore volume, and functional group type were not obviously affected. The specific surface area and pore volume of hydrochar decreased by 61.8% and 70.9% as LSR reduced to 1:1, due to incomplete carbonization. According to the gray relation, hydrochar derived at LSR of 10:1 and followed by 2:1 showed greatest relation degree of 0.80 and 0.70, respectively, indicating better soil application potential. However, reducing LSR from 10:1 to 2:1 made the income of single process production increased from −388 to 968 ¥, and the wastewater generation decreased by 80%. Considering the large-scale application of HTC in fields for farmland improvement and environmental remediation, the comprehensive advantages of optimized LSR will be further highlighted.

Recent Advances in Wearable Tactile Sensors Based on Electrospun Nanofiber Platform

AbstractWearable electronics have triggered the great development of flexible tactile sensors for promising applications such as healthcare monitoring, motion detection, and human‐machine interaction. However, most of the flexible sensors are constructed on compact and airtight polymer films with inferior flexibility and no breathability, hindering the wearability and comfortability for long‐time continuous operation usage. To address such challenges, flexible sensors based on the electrospun polymer platform with comprehensive advantages of ultrathin thickness, superior flexibility, excellent stretchability, high porosity, low density, and surface functionality are emerging. It has become a hot research direction, and considerable progress has been made. Therefore, it is necessary to timely review the latest findings on the rapidly developing electrospun nanofiber‐based tactile sensors. Firstly, the principle of the electrospinning technique, the factors affecting the nanofiber morphology, and the engineering of the nanofibers are briefly introduced, and the key material and structural factors affecting the sensing performance are analyzed. Secondly, representative work on the electrospun nanofiber‐based tactile sensors is discussed in detail according to the sensing mechanism. Thirdly, unique properties of electrospun nanofibers, such as superior flexibility, breathability, hydrophobicity, anti‐bacterial, and self‐cleaning, are highlighted. Finally, the remaining challenges and future development trends are outlined.

On the readability of texts presented in sentence-by-sentence segments to beginner readers: Evidence from self-paced reading and eye tracking

Many digital reading applications have built-in features to control the presentation flow of texts by segmenting those texts into smaller linguistic units. Whether and how these segmentation techniques affect the readability of texts is largely unknown. With this background, the current study examined a recent proposal that a sentence-by-sentence presentation mode of texts improves reading comprehension of beginning readers because this presentation mode encourages them to engage in more effortful sentence wrap-up processing. In a series of self-paced reading and eye-tracking experiments with primary school pupils as participants (6–9 years old; n = 134), reading speed and text comprehension were assessed in a full-page control condition—i.e., texts were presented in their entirety—and in an experimental condition in which texts were presented in sentence-by-sentence segments. The results showed that text comprehension scores were higher for segmented texts than for full-page texts. Furthermore, in the final word-regions of the sentences in the texts, the segmented layout induced longer reading times than the full-page layout did. However, mediation analyses revealed that these inflated reading times had no, or even a disruptive influence on text comprehension. This indicates that the observed comprehension advantage for segmented texts cannot be attributed to more effortful sentence wrap-up. A more general implication of these findings is that the segmentation features of reading applications should be used with caution (e.g., in educational or professional settings) because it is unclear how they affect the perceptual and cognitive mechanisms that underlie reading.

Lightweight metal laminated plates produced via (hot, cold and cryogenic) roll bonding: A review

Due to the comprehensive advantages of various metals, metal laminates have been paid much attention. Roll bonding method has become one of the main fabrication methods of metal laminates, benefiting from the advantages of stable and continuous production. The research progress in the roll bonding of metal laminates is reviewed, mainly including the hot roll bonding, cold roll bonding, accumulative roll bonding and cryogenic roll bonding. The formation mechanism of bonding interface and the main influence factors on the interfacial bonding quality are systematically discussed. Moreover, further prospects are pointed out on the advancement of high-performance roll bonding of metal laminates.

Ti-Doped SnO2 Supports IrO2 Electrocatalysts for the Oxygen Evolution Reaction (OER) in PEM Water Electrolysis

The development of polymer electrolyte membrane electrolysis of water is mainly limited by the high cost of noble metals and inadequate stability owing to the slow reaction kinetics of the oxygen evolution reaction and the restrictions of strongly acidic operating environments. To improve the utilization of noble metals, we use Ti-doped SnO2 as a carrier to support active species IrO2. The results show that the introduction of Ti element can inhibit the grain growth and help to improve the electrical conductivity of SnO2. Electrochemical tests for the catalysts show that 40 wt % IrO2/TSO has the best mass-normalized charge (231.24 C g–1 IrO2) and current density (714.85 A g–1 IrO2) at 1.6 V with the overpotential of only 271 mV at 10 mA cm–2, which is attributed to the outstanding dispersion effect of Ti-doped SnO2 and the synergy between the active species and the introduction of Ti element. The comprehensive advantages exhibited by the Ti-doped SnO2 support provide an alternative solution to reduce the cost of noble metal catalysts by improving the catalytic activity and stability.

The inventory replenishment policy in an uncertain production-inventory-routing system

&lt;p style='text-indent:20px;'&gt;This study introduces an uncertain programming model for the integrated production routing problem (PRP) in an uncertain production-inventory-routing system. Based on uncertainty theory, an uncertain programming model is proposed firstly and then transformed into a deterministic and equivalent model. The study further probes into different types of replenishment policies under the condition of uncertain demands, mainly the uncertain maximum level (UML) policy and the uncertain order-up to level (UOU) policy. Some inequalities are put forward to define the UML policy and the UOU policy under the uncertain environments, and the influences brought by uncertain demands are highlighted. The overall costs with optimal solution of the uncertain decision model grow with the increase of the confidence levels. And they are simultaneously affected by the variances of uncertain variables but rely on the value of confidence levels. Results show that when the confidence levels are not less than 0.5, the cost difference between the two policies begins to narrow along with the increase of the confidence levels and the variances of uncertain variables, eventually being trending to zero. When there are higher confidence levels and relatively large uncertainty in realistic applications, in which the solution scale is escalated, being conducive to its efficiency advantage, the comprehensive advantages of the UOU policy is obvious.&lt;/p&gt;

A Fault Diagnosis Method for Rolling Bearing Based on 1D-ViT Model

Rolling bearings are the key component of large rotating machinery. When such components fail completely, the equipment will be out of service, causing significant economic loss, and even leading to safety accidents, threatening the lives of workers. However, it is difficult to detect the early failure symptom of rolling bearings during the routine maintenance. Advanced fault diagnosis tools are limited in cost and technology. Therefore, researchers focus on how to implement accuracy and convenience of fault diagnosis method. This paper proposes a fault diagnosis method for rolling bearings based on 1D-vision transformer (1D-ViT) encoder structure, which applies vision transformer (ViT) model to the fault diagnosis area. The end-to-end fault diagnosis can be realized by directly inputting the original one-dimensional acquired data without additional time-frequency domain conversion. After the encoder ablation experiment, the model structure was optimized. With the rolling bearing data set of Southeast University and Case Western Reserve University (CWRU), the number of floating point operations (FLOPs) is as low as 0.169G, the parameter number is as low as 4.13M, and average accuracy is 99.9%, which also has better noise-resistance performance. Compared with common classification models, the 1D-ViT model has achieved great comprehensive advantages in fault diagnosis accuracy, time complexity, space complexity and noise-resistance performance, which verifies the effectiveness and convenience of the proposed fault diagnosis method.

The Current State and Future Prospects of Different Types of New Energy Vehicles

With the advent of the electrification era of passenger cars, the development and trend of new energy vehicles have attracted growing public attention. The focus of this paper is to compare the merits and demerits of different types of new energy vehicles and to look forward to their future development prospects. Based on the sales situation of NEVs in recent years, the proportion of NEVs in the current market and the existing conditions of different types of NEVs, this paper analyzes the current market structure and looks forward to the future development of new energy vehicles. The paper finds that pure electric vehicles and plug-in hybrid vehicles are the two main players in the new energy vehicle market. In the era of automobile electrification, pure electric vehicles have unique comprehensive advantages, which is the development direction of the passenger car industry. Hybrid vehicles are used as an auxiliary for their coordinated development. Hydrogen energy vehicles are currently not as selected by the public as pure electric series and hybrid series, but hydrogen energy is another new energy development direction in addition to electric energy, and there is also much room for its development with the national support. Natural gas fuel vehicles currently have a small market and can also give full play to their advantages in the transition stage of development.

Adaptive Fast Chirplet Transform and Its Application Into Rolling Bearing Fault Diagnosis Under Time-Varying Speed Condition

Tacholess order tracking is a commonly-used technique for the fault diagnosis of bearing with time-varying speed, in which time-frequency analysis (TFA) is a key step for estimating the rotation frequency. The current TFA methods are either weak in energy concentration or have high computational complexity. To this end, an adaptive fast chirplet transform (AFCT) based on the adaptive optimal search angle band is proposed in this paper. The proposed method uses the modulation operator of synchrosqueezed transform to adaptively optimize the search band of the frequency modulation parameters, which overcomes the problem of low computational efficiency in chirplet transform (CT) and its variants. Moreover, a novel time-frequency energy concentration evaluation index mean-energy-to-peak-ration (MEPR) is proposed. The simulation result shows that the proposed method has both good time-frequency concentration performance and low computational complexity. Especially, its calculation speed is much faster than other TFA methods with high time-frequency resolution. The proposed method is successfully applied to estimate the rotation frequencies from the fault vibration signals from a test rig and a civil aircraft engine. The comparative results verify the comprehensive advantage of the proposed method in ridge extraction accuracy and computational efficiency compared to the existing classical TFA methods. With the proposed method, the fault features of rolling bearings under time-varying speed can be effectively extracted.

Nanoparticle-based applications by atmospheric pressure matrix assisted desorption/ionization mass spectrometry.

Recently, the development of atmospheric pressure matrix assisted desorption/ionization mass spectrometry (AP MALDI MS) has made contributions not only to biomolecule analysis but also to spatial distribution. This has positioned AP MALDI as a powerful tool in multiple domains, thanks to its comprehensive advantages compared to conventional MALDI MS. These developments have addressed challenges associated with previous AP MALDI analysis systems, such as optimization of apparatus settings, synthesis of novel matrices, preconcentration and isolation strategies before analysis. Herein, applications in different fields using AP MALDI MS were described, including peptide and protein analysis, metabolite analysis, pharmaceutical analysis, and mass spectrometry imaging.

Self-rolling of vanadium dioxide nanomembranes for enhanced multi-level solar modulation

Thermochromic window develops as a competitive solution for carbon emissions due to comprehensive advantages of its passivity and effective utilization of energy. How to further enhance the solar modulation ({triangle T}_{{{{{{{rm{sol}}}}}}}}) of thermochromic windows while ensuring high luminous transmittance ({T}_{{{{{{{rm{lum}}}}}}}}) becomes the latest challenge to touch the limit of energy efficiency. Here, we show a smart window combining mechanochromism with thermochromism by self-rolling of vanadium dioxide (VO2) nanomembranes to enhance multi-level solar modulation. The mechanochromism is introduced by the temperature-controlled regulation of curvature of rolled-up smart window, which benefits from effective strain adjustment in VO2 nanomembranes upon the phase transition. Under geometry design and optimization, the rolled-up smart window with high {triangle T}_{{{{rm{sol}}}}} and {T}_{{{{{{rm{lum}}}}}}} is achieved for the modulation of indoor temperature self-adapted to seasons and climate. Furthermore, such rolled-up smart window enables high infrared reflectance after triggered phase transition and acts as a smart lens protective cover for strong radiation. This work supports the feasibility of self-rolling technology in smart windows and lens protection, which promises broad interest and practical applications of self-adapting devices and systems for smart building, intelligent sensors and actuators with the perspective of energy efficiency.

Construction of PdS@MIL-125-NH2@ZnS type-II heterostructure with efficient charge separation for boosted photocatalytic hydrogen evolution

A new photocatalyst, PdS@NH2-MIL-125(Ti)@ZnS (PdS/M125/ZnS) heterojunction is fabricated for photocatalytic H2 generation for the first time, where PdS nanoparticles are anchored in the pore of M125 by utilizing its confinement effect, and the ZnS is closely wrapped on the surfaces of the MOFs. The optimal photocatalyst exhibits a significantly enhanced H2 generation rate of 1164.2 μmol/g/h, while the pure M125 only displays a H2 generation rate of 16.7 μmol/g/h. The resultant improvement can be ascribed to the following comprehensive advantages. The hierarchical structure built by PdS, M125, and ZnS can form lots of intimate interfaces, offer abundant sites for reaction, and smooth channels for charge carriers due to the porous characteristics of MOFs. Moreover, M125 and ZnS with inner defect levels form an analogous type-II heterojunction assisted by PdS co-catalyst, which greatly promotes charge separation. This work may supply a new avenue to design MOFs photocatalysts for energy conversion.

Company growth and growth opportunities on the example of some EU stock exchanges in the light of market characteristics

This paper analyzes the relationship between growth opportunity measures and the future growth of companies. If there is a correlation between a company’s growth potential and its real growth, then the markets are more predictable and effective. The survey was conducted on the example of the following European markets: Austria, the Baltic Countries, Hungary, France, Poland, and Germany. The goal of this paper is to assess the relationship between growth opportunity measures and the future growth of companies listed on the stock exchanges of some markets in the European Union. The countries considered can be classified according to the size of the state, market liquidity, and the maturity of the exchange. Those external factors were expected to influence the strength of the growth and its opportunity relationship. It was found that growth opportunity measures based on market prices have predicting power for the future growth of companies. They are also strongly related to companies’ future growth in large countries and weakly related to future growth in small countries. This paper adds to the literature on the application of growth opportunity measures regarding market characteristics. These results are in line with the view that market liquidity should increase its efficiency in revealing the value of stocks and the Comprehensive Advantage of Large Countries hypothesis.

Investigation of Half Rectangular-Ring Helix Slow Wave Structure for W-Band Wide Bandwidth High-Efficiency TWTs

The half rectangular-ring helix (HRRH) slow wave structure (SWS), which evolves from the rectangular helix (RH), is proposed to develop a high-efficiency wide bandwidth millimeter-wave traveling-wave tube (TWT). The comprehensive advantages of the HRRH SWS are lower phase velocity and higher interaction impedance in comparison with the RH and the planar helix with straight-edge connections (PH-SECs) SWS with the same dimensions. The particle-in-cell (PIC) simulation shows that, at a beam voltage of 6450 V, a beam current of 0.03 A, the maximum output power of 42.2 W, corresponding to a differential small-signal gain of 1.43 dB/mm, and an electron efficiency of 21.8% can be obtained for the HRRH TWT at 95 GHz. The output power, differential small-signal gain, and electron efficiency of the HRRH TWT are considerably enhanced compared with the RH TWT in a wide frequency range of 60–115 GHz under the same electrical parameters.

B, N co-doped carbon dots based fluorescent test paper and hydrogel for visual and efficient dual ion detection

It is highly significant to develop water-soluble carbon dots (CDs) for ion detection in the environment via a facile and economical process. Herein, the organic molecules derived boron, nitrogen co-doped CDs (BN-CDs) with water-solubility are solvothermally synthesized towards dual ion detection. The BN-CDs emit bright tangerine fluorescence, and demonstrate a fluorescent quantum yield of 17 %. Besides, the obtained BN-CDs show a good linear relationship with Cu2+/Co2+ in a wide dynamic range of 1–8 μM, along with detection limits of 16 nM (Cu2+) and 24 nM (Co2+). The joint effect of dynamic and static quenching mechanisms is proposed as well for fluorescence quenching by Cu2+/Co2+. Furthermore, two instrument-free BN-CDs-based solid sensors (i.e., test strips and hydrogel beads) are fabricated to sensitively monitor both Cu2+ and Co2+. The paper-based sensors exhibit selective and sensitive response towards Cu2+ and Co2+ in a low-cost manner. The fluorescence hydrogel integrates comprehensive advantages of hydrogel and BN-CDs, which makes it not only conduct as efficient fluorescent sensors to detect Cu2+ and Co2+ but act as the absorbent towards removal of the ions. The simple yet reliable sensing technique developed here favor efficiently detecting and recognizing dual ions in environmental and/or biological samples.