Transmission Elements Research Articles

Core-shell upconversion nanoparticles with suitable surface modification to overcome endothelial barrier.

Upconversion nanoparticles (UCNPs), capable of converting near-infrared (NIR) light into high-energy emission, hold significant promise for bioimaging applications. However, the presence of tissue barriers poses a challenge to the effective delivery of nanoparticles (NPs) to target organs. In this study, we demonstrate the core-shell UCNPs modified with cationic biopolymer, i.e., N, N-trimethyl chitosan (TMC), can overcome endothelial barriers. The core-shell UCNP is composed of NaGdF4: Yb3+,Tm3+ (16.7 ± 2.7 nm) as core materials and silica (SiO2) shell. The average particle size of UCNPs@SiO2 is estimated at 26.1 ± 3.7 nm. X-ray diffraction (XRD), transmission electron microscopy (TEM) and element mapping shows the formation of hexagonal crystal structure of β-NaGdF4 and elements doping. The surface of UCNPs@SiO2 has been modified with poly(ethylene glycol) (PEG) to enhance water dispersibility and colloidal stability, and further modified with TMC with the zeta potential increasing from -2.1 ± 0.96 mV to 26.9 ± 12.6 mV. No significant toxic effect is imposed to HUVECs when the cells are treated with core-shell UCNPs with surface modification up to 250 µg/mL. The transport ability of the core-shell UCNPs has been evaluated by using the in vitro endothelial barrier model. Transepithelial electrical resistance (TEER) and immunofluorescence staining of tight junction proteins have been employed to verify the integrity of the in vitro endothelial barrier model. The results indicate that the transport percentage of the UCNPs@SiO2 with PEG and TMC through the model is up to 4.56%, which is twice higher than that of the UCNPs@SiO2 with PEG but without TMC and six times that of the UCNPs@SiO2.

Capabilities of Software Package Gearacl for Design Gearings and Transmission Elements

Creation of a mathematical model of gearing operation belongs to one of the most knowledge-intensive fields of knowledge. Interdisciplinary research is being conducted to develop the model. For practical use, the results of this work are embodied in strength analysis standards. Due to the complexity of the processes occurring in gearings, performing analysis of one pair of gears today requires not only significant time costs from the engineer, but also a deep understanding of hundreds of pages of calculation techniques described by groups of interrelated standards. The calculation formulae include clarifying coefficients, the contribution and values of which are determined by a group of specialists developing the standard, based on research of analysis result coordination, experimental data and calculations performed using the finite element method. To perform the analysis, the designer needs knowledge about the principles of choosing coefficient values and their meaning. Performing the analysis of gearings according to the standard is a time-consuming process that can be correctly performed only by an engineer with experience in designing gearings. To facilitate the work of the engineer, software products both domestic and foreign were created. However, the trends of recent years require replacement of foreign software products. In 2022, the specialists of the Central Institute of Aviation Motors developed the Gearacl software package, which allows replacing foreign products in the volume required by the aviation industry enterprises in the field of cylindrical gearings, shafts and bearings analysis. Modern analysis methods have been introduced into the software package. This article is devoted to the capabilities of the Gearacl software package.

Optical information hiding system with pixel-free expansion visual cryptography

Abstract We propose an optical information hiding system with pixel-free expansion visual cryptography (PEVC). In the optical concealment process, initially, a PEVC scheme is utilized to encode the secret image. This approach generates visual keys of the same size as the secret image, addressing the pixel expansion issue inherent in visual cryptography encoding schemes. As a result, it significantly reduces both storage space requirements and the network bandwidth occupied during the transmission process and exhibits a higher hidden capacity. Furthermore, PEVC is combined with the optical phase retrieval algorithm for hiding, embedding the visual keys into the phase keys. In this process, wavelength and diffraction distance are introduced as keys, enhancing the security of the system. The phase keys can be fabricated into diffractive optical elements for physical preservation and transmission in tangible form. Simulation experiments and optical experimental results indicate that the system is applicable in practical scenarios and possesses excellent security and exhibits a higher hidden capacity.

Sliding mode control based on maximum power point tracking for dynamics of wind turbine system

This article presents a proportional-integral sliding mode control (PI-SMC) approach for a two-mass variable speed wind turbine (VSWT) system. Most studies on wind turbines typically focus mainly on the electromagnetic part of the generators, or even on the high-speed part, considering the shaft stiffness as negligible. However, the generator torque is actually driven by the aerodynamic torque, and a two-mass system like the one studied here plays the role of a transmission element for this power. To address this challenge, the problem of low power generation resulting from wind speed variability is tackled by designing a PI-SMC control law, capable of controlling the mechanical turbine model that optimizes power and torque by tracking the maximum power point (MPPT) for rotational speed and aerodynamic power. To validate the developed theoretical results, an application of the wind turbine system is simulated in Matlab/Simulink, for a particular case. The control used is capable of satisfying the dynamic performance of the systems.

A nN[formula omitted]m level micromotor holding torque measurement method

Efficient and high-precision torque measurement methods for micromotors are globally critical, impeding the advancement of microsystems, particularly ultrasonic micromotors, known for their small size, high speed and high resolution. This paper proposes a novel torque measurement method for ultrasonic micromotors, establishing a torque measurement device that utilizes a parallelogram flexible hinge as the force transmission element. This approach can measure torque at the nano-Newton-meter (nN⋅m) level. The system demonstrates high measurement accuracy, robust anti-interference capability, and a wide measurement range. When the 18 V voltage is applied to the motor, the holding torque is 234.66 nN⋅m, the repeatability error of the system is 1.25%, and the combined standard uncertainty is 5.36 nN⋅m. The proposed method is a pivotal step towards filling the existing technological void, offering a substantial impact on the development of ultrasonic micromotors and the broader field of microsystems.

Boosting carbon capture with CO2-Ultrapermeable molecularly imprinted membranes

Mixed matrix membrane (MMM) is one of the most promising candidates for exceeding the gas separation upper bound, while fillers can largely determine their ultimate performance. The molecular imprinting technique was first employed to prepare a layer containing rich CO2 adsorption sites on the UiO-66-NH2 surface for fabricating highly CO2-permeable PIM-1-based MMMs with higher selectivity. Transmission electron microscopy (TEM) and element mapping confirmed the successful formation of the core-shell structure for the imprinted metal-organic frameworks (MOFs). The MMMs prepared with imprinted MOFs present enhanced CO2 permeability and CO2/N2 selectivity, higher compatibility between polymers and fillers, and better mechanical strength compared to the MMMs with the pristine UiO-66-NH2. The MMMs formed with 5 wt% imprinted MOFs showed superior CO2/N2 separation performance beyond the 2019 upper bound with an ultrahigh CO2 permeability of 13,000 barrer (increased twice compared to pristine PIM-1 membrane). Moreover, with a filler content of 13 wt%, the obtained membrane maintains good mechanical properties, which indicates the benefit of the imprinted layer for the improvement of the filler loading inside a PIM-1 matrix. The membranes showed decreased CO2 permeability and CO2/N2 selectivity under the wet conditions, but stable performances over 46 hours of dynamic testing. The results indicate the presented approach for filler modification via molecular imprinting is a promising strategy for the enhancement of the MMM separation performance.

Optical transmission trajectories in single tapered fibers of TOFA by numerical simulation and experimental verification

Tens of millions or billions of single tapered fibers are independent optical transmission elements of tapered optical fiber array (TOFA) for imaging. The optical transmission trajectories of these single tapered fibers, which directly affect imaging qualities of TOFA, are rarely analyzed. This paper provides a method to numerically simulate it for fibers located at different positions along the radial direction of TOFA. The tapered curves of TOFA were firstly simulated by Finite Element Analysis (FEA) software and experimentally verified by the same preparation parameters. It is shown that the slope of tapered curve increases with stretching length. Meanwhile, the taper angle gets greater, and the profile of tapered deformation zone expands outward, while the radius of straight zone remains stable. Based on these, the optical transmission trajectory of single tapered fibers located from center to edge in TOFA was simulated, and then further verified by a self-developed instrument. Both simulation and experiment illustrate that the relative transmittance of single tapered optical fiber is decreased along the radial direction within the same TOFA. In comparison with the transmittance of the central axial fiber, the simulated and experimental unevenness on relative transmittance of peripheral fibers is within 7.11% and 9.74%, respectively. With the relative transmittance at the central position of the optical fiber being identical, the difference of relative transmittance (ΔT) between the simulation and experiment is gradually increased from center to peripheral regions along the radial direction of TOFA, reaching the maximum ΔT of 4.23%. The simulated results are well in agreement with the experimental ones.

The anisotropic and region-dependent mechanical response of wrap-around tendons under tensile, compressive and combined multiaxial loads

The present work reports on the multiaxial region and orientation-dependent mechanical properties of two porcine wrap-around tendons under tensile, compressive and combined loads based on an extensive study with n=175 samples. The results provide a detailed dataset of the anisotropic tensile and compressive longitudinal properties and document a pronounced tension-compression asymmetry. Motivated by the physiological loading conditions of these tendons, which include transversal compression at bony abutments in addition to longitudinal tension, we systematically investigated the change in axial tension when the tendon is compressed transversally along one or both perpendicular directions. The results reveal that the transversal compression can increase axial tension (proximal-distal direction) in both cases to orders of 30%, yet by a larger amount in the first case (transversal compression in anterior-posterior direction), which seems to be more relevant for wrap-around tendons in-vivo. These quantitative measurements are in line with earlier findings on auxetic properties of tendon tissue, but show for the first time the influence of this property on the stress response of the tendon, and may thus reveal an important functional principle within these essential elements of force transmission in the body. Statement of significanceThe work reports for the first time on multiaxial region and orientation-dependent mechanical properties of wrap-around tendons under various loads. The results indicate that differences in the mechanical properties exist between zones that are predominantly in a uniaxial tensile state and those that experience complex load states. The observed counterintuitive increase of the axial tension upon lateral compression points at auxetic properties of the tendon tissue which may be pivotal for the function of the tendon as an element of the musculoskeletal system. It suggests that the tendon’s performance in transmitting forces is not diminished but enhanced when the action line is deflected by a bony pulley around which the tendon wraps, representing an important functional principle of tendon tissue.

Continuously Variable Two-Flow Hydrostatic-Mechanical Transmission of Crawler Tractor

The paper proposes an original design of a continuously variable two-flow hydrostatic-mechanical transmission, which ensures division of the power flow along the sides of the crawler tractor. To ensure stability of rectilinear motion, their volumetric and mechanical efficiency, the maximum pressure of the working fluid in the hydraulic transmission, the maximum speed and torque on the shaft of the hydraulic motor. The parameters of an unregulated hydraulic motor, an adjust-table pump and mechanical transmission elements are selected. A mathematical model of the rectilinear motion of a caterpillar tractor with a continuously variable hydrostatic-mechanical transmission has been developed, taking into account the weight of the tractor, the parameters of the running system, the characteristics of the internal combustion engine, the parameters and efficiency of hydraulic machines, gearboxes, range and transfer boxes, planetary gear and allowing to determine the efficiency of individual branches and the entire transmission, carry out traction calculations of the tractor. A calculation program has been developed that implements the mathematical model. The parameters of the dual-flow transmission are selected so that most of the torque is transmitted through the mechanical branch and the transmission has a fairly high efficiency value. The maximum value of tractor traction efficiency is realized in the second and third ranges, which are designed to perform basic tillage operations.

A Wideband Conformal Array Antenna With Dual-Polarized Transmission and Reflection Element for Full-Space Beam-Scanning Capability

A Wideband Conformal Array Antenna With Dual-Polarized Transmission and Reflection Element for Full-Space Beam-Scanning Capability

MOF-derived porous In2O3 nanospheres sensitized by CdS quantum dots: A ppb-level NO2 sensor with ultra-high response at room-temperature

NO2 is one of the most important atmosphere pollutants, causing great harm to the human body at very low concentrations (ppb levels). Herein, a novel fabrication idea for gas sensing materials was reported to detect ppb-level NO2 via MOF-derived porous In2O3 nanospheres (NSs) sensitized by CdS quantum dots (QDs). The good distribution of CdS QDs (2.5–4.0 nm) on porous In2O3 NSs was verified by the transmission electron microscopy and element mapping analyses. In comparison to In2O3 NSs, the CdS@In2O3 composite nanospheres (CNSs) exhibited exceptional responses to ppb-level concentrations of NO2 (S=425.1@100 ppb) at room temperature (RT, 25 °C), while also demonstrating good selectivity and response reproducibility. These improvements in sensing performance were attributed to the synergies of the electronic effects of CdS QDs, MOF-derived porous nanostructures, and enhanced adsorption of NO2 and active O2– by well-dispersed CdS QDs. This work emphasizes that the MOF-derived In2O3 porous NSs sensitized by CdS QDs can accurately detect ppb-level concentrations of the NO2 at RT.

High transmission efficiency collection system for laser-accelerated proton beams based on permanent magnet quadrupoles prefocusing

A new high transmission efficiency, easily tunable, and cost-effective beam collection system is proposed for laser-accelerated proton beams with large divergence angles and wide energy spectra. In previous experiments conducted at the compact laser plasma accelerator platform of Peking University, a beamline was initially constructed with a collection system based on an electromagnetic quadrupoles (EMQs) triplet. However, due to the limited acceptance angle, the EMQs exhibited a monoenergetic transmission efficiency of only 10% to 20% for laser accelerated proton beams. Permanent magnet quadrupoles (PMQs), known for their high magnetic field gradients, compact size, and lower expenses, are well suited for integration with other readily adjustable transmission elements like EMQs and solenoids, effectively enhancing the beam collection capabilities of the system. In this paper, we show that by introducing a pair of centimeter-sized PMQs in front of the EMQs for beam prefocusing, the beam’s transverse size is quickly compressed, enabling transmission of highly divergent protons. Experimental results demonstrate that the prefocusing by PMQs increased the system’s transmission efficiency by a factor of 2.44 to 6.01 compared to the original setup, while also enhancing the energy selection based on stronger chromatic effect. This method can be extended to 100 MeV high-energy proton beamlines and is crucial for applications of laser plasma accelerators. Published by the American Physical Society 2024

예전과 기독교 교육 : 신앙형성과 전수를 위한 핵심축

예전과 기독교 교육 : 신앙형성과 전수를 위한 핵심축

Synergistic effect of Sn + Sc on high temperature strengthening in Al–5Cu heat-resistant alloy

By adding Sn and Sc alone or in combination, as well as conducting a tensile test at 573 K, the synergistic effect of Sn + Sc on high-temperature strengthening in Al–5Cu heat-resistant alloy was investigated. Transmission electron microscope, elements mapping and first-principle calculations were used to characterise the microstructure evolution of the precipitation particles at various states to uncover the processes for high-temperature strengthening. It has been discovered that adding Sn and Sc, either individually or together, can significantly improve the mechanical properties of Al–Cu alloy at elevated temperatures. Among them, the alloy performance under short-time 573 K exposure can be maximised when Sn and Sc elements are added together.

Critical Breakdown Electric Field of Sulfur Dioxide at 1–10 Bar and 300–4000 K for Applications in Power Transmission and Switching Elements

Critical Breakdown Electric Field of Sulfur Dioxide at 1–10 Bar and 300–4000 K for Applications in Power Transmission and Switching Elements

Overlapping Streptococcus pyogenes and Streptococcus dysgalactiae subspecies equisimilis household transmission and mobile genetic element exchange

Streptococcus dysgalactiae subspecies equisimilis (SDSE) and Streptococcus pyogenes share skin and throat niches with extensive genomic homology and horizontal gene transfer (HGT) possibly underlying shared disease phenotypes. It is unknown if cross-species transmission interaction occurs. Here, we conduct a genomic analysis of a longitudinal household survey in remote Australian First Nations communities for patterns of cross-species transmission interaction and HGT. Collected from 4547 person-consultations, we analyse 294 SDSE and 315 S. pyogenes genomes. We find SDSE and S. pyogenes transmission intersects extensively among households and show that patterns of co-occurrence and transmission links are consistent with independent transmission without inter-species interference. We identify at least one of three near-identical cross-species mobile genetic elements (MGEs) carrying antimicrobial resistance or streptodornase virulence genes in 55 (19%) SDSE and 23 (7%) S. pyogenes isolates. These findings demonstrate co-circulation of both pathogens and HGT in communities with a high burden of streptococcal disease, supporting a need to integrate SDSE and S. pyogenes surveillance and control efforts.

A novel bifunctional metasurface based on independent control of transmission and reflection amplitudes and phases

ABSTRACT A novel bifunctional metasurface (MS) operating at two frequencies is proposed to manipulate reflected and transmitted waves independently. The element is composed of a slot sandwiched by two C-shape spilt rings (CSRRs). The middle layer is the metal sheet etched the slots, and it is used to select polarization mode of reflection and transmission. Also, it isolates the reflection and transmission elements and eliminates the coupling between them. Therefore, the reflection or transmission amplitude and phase of the proposed MS can be regulated by the corresponding single metal layer compared with the current bifunctional elements. This is helpful to shorten design time. Also, a higher transmission amplitude is achieved with fewer substrate layers and lower profile. The reflection and transmission mode operate at 17.6 GHz and 12.6 GHz, respectively. As a proof of concept, a full-space multibeam generator is validated both numerically and experimentally and a full-space bifocal metalens is demonstrated numerically. The proposed MS provides a new kind of low cost, lightweight, and easily modularized planar devices for microwave applications.

Analysis and Characterization of Castellated Holes as RF Interconnects for Modular Millimeter-Wave Devices

This paper presents an innovative approach to the use of Castellated Holes or Plated Half Holes (PHH) as transmission elements for high frequency interconnections between printed circuit boards in a frequency range of up to 40 GHz. The basic design was examined using commonly used design parameters for PCB modules with Castellated Holes which were then investigated and subsequently optimized to improve their RF performance, with a particular focus on design considerations according to today’s industrial manufacturing capabilities. Therefore the FEM-based full wave simulation technique was used to compare and optimize the design parameters in the aim to improve the capability of PHHs as low-loss, low-disturbant RF interconnection alternative in modular PCB designs. Based on these results test samples were developed, which were subsequently measured and thus verified the findings of the simulation. To provide a general comparability, this study focused on the S-Parameter to quantify the performance in terms of transmission losses and reflection. With an optimized design feasible results were achieved with a maximum transmission loss of less than 2 dB at the maximum of the desired frequency range and about 1dB at 20 GHz over the entire signal path. These insights make PHHs suitable for seamless integration into modular designs in RF and millimeter-wave applications.

Wear Reduction on the Roller–Shoe Mechanism at High Operation Loads

The roller–shoe mechanism is a classic mechanical assembly with an essential role in motion transmission. Common rail high-pressure pumps are an example of a complex assembly that uses such a mechanism to transform the rotation motion into a translation one. The rolling element of the mechanism is represented by a cylindrical roller. Although it can carry heavy loads due to its design, a proper surface profile could significantly increase the life of the entire mechanism. A better solution can be achieved using a logarithmic profile. The shoe is the second base element of the mechanism. It is a part with an inner cylindrical surface and it is separated from the roller by a thin lubricant film. Considering this, increasing the hardness of the roller–shoe contact surface can be obtained using a suitable coating. The positive results of this coating are highlighted using endurance tests to which high-pressure pumps are subjected. Therefore, the roller profile and the shoe coating represent two directions for improving the contact between the mechanism transmission elements, in terms of wear reduction. The purpose of this paper is to identify a suitable roller profile and to highlight its impact on the shoe coating.

Condition monitoring of Industrial machine’s transmission elements – MSDF feature extraction approach

ABSTRACT Predictive maintenance is a modern Industry 4.0 strategy in which machines are continuously monitored to detect flaws and prevent breakdowns before they occur. A single sensor focuses on a single variable while neglecting larger information components, resulting in poor data quality and an increased risk of issues in critical rotating equipment. Multi-sensory configuration technology has been developed to collect huge amounts of data from a machine in order to enhance monitoring capabilities in terms of precision, resolution, efficiency, resilience, and trustworthiness of the overall system. The goal of this work is to provide an integrated perspective on machine monitoring using the Multi Sensor Data Fusion (MSDF) technique. On four fault bearings, a case study contrasts the results of single and multiple sensors. A feature-level data fusion method is used, in which computations using time-domain vibration signature data are utilised to build a fusional vector, which is then classified using SVM and analysed with Gaussian kernels. The experimental results suggest that the proposed Gaussian kernel with SVM technique outperforms single sensor data interpretation in terms of classification accuracy and generalisation capability. It is an efficient way for finding defects in rotating machinery in excessively noisy environments.