High Connection Research Articles

Experimental and numerical investigations on the mechanical behavior of composite pre-tightened tooth connection under impact loading

The composite Pre-Tightened Tooth Connection (PTTC) is characterized by high connection efficiency and large bearing capacity, specifically designed for use in fiber-reinforced polymer (FRP)-metal protective structures that are inherently subjected to impact loads. In this study, impact tests were performed on single- and double-tooth specimens under high-velocity impact loads using the Split Hopkinson Pressure Bar (SHPB) apparatus to investigate their impact behavior. Additionally, a progressive damage model was numerically developed and validated against the experimental results to examine the failure patterns and mechanisms of the PTTC. The effects of tooth depth, tooth length, number of teeth, and impact velocity on the impact behavior were also analyzed parametrically. The results indicated that the primary failure modes of the PTTC are ductile compression-shear failure and brittle shear failure. In cases of compression-shear failure, the bearing capacity is lower than that of shear failure; however, it exhibits superior energy absorption characteristics. Therefore, it is recommended that the PTTC be designed to facilitate compression-shear failure when subjected to high-velocity impact. The length, depth, and number of teeth significantly influence the failure mode, bearing capacity, and energy absorption of the PTTC. Adequate design attention should be given to these factors for applications involving impact loads.

Facilitators and barriers to survivorship support access: a qualitative study of rectal cancer survivors’ experiences in Texas

ObjectiveThis qualitative study aimed to analyse rectal cancer survivors’ lived experiences to identify facilitators and barriers to support access.DesignWe conducted one-on-one semi-structured interviews and employed thematic analysis to identify key...

Designing S-scheme heterojunction via in situ converting partial NH2-MIL-68 into defective In2O3 for photocatalytic CO2 reduction

Intrinsic characteristics of metal–organic frameworks (MOFs) make them become promising candidates for the application of photocatalytic CO2 reduction. However, their photocatalytic activities are still unsatisfactory due to serious recombination of photogenerated charge carriers and insufficient light absorption. S-scheme heterojunction has demonstrated high superiority in the separation of charge carriers due to its unique structure and interface interaction. Nevertheless, it is difficult to construct it in MOF-based photocatalysts because of high interface connection requirements. Herein, a NH2-MIL-68 (In-MOF) is chosen as the research object. S-scheme heterojunction (In2O3@In-MOF) with oxygen vacancies (OVs) is easily constructed via in situ converting partial In-MOF into defective In2O3. The in-situ derivatization strategy is similar to epitaxial crystal growth, which could avoid drastic changes in the morphology of epitaxial growth rh-In2O3 to ensure the high-quality interface connection. The S-scheme heterojunction not only enhances the separation efficiency of photogenerated charge carriers of In-MOF, but also maintains the high reduction power of its photogenerated electrons as well as expanding its light absorption capacity. Therefore, In2O3@In-MOF exhibits enhanced photocatalytic CO2 reduction activity compared to those of pure In-MOF and In2O3. This work may open a potential pathway for the S-scheme heterojunction designing in the field of photocatalytic CO2 reduction.

A Method to Construct FE Model Simulating the Cyclic Behavior of High Strength WUF-W Connections

A Method to Construct FE Model Simulating the Cyclic Behavior of High Strength WUF-W Connections

How the synergy of government intervention and digital transformation affects carbon emission: evidence from a quasi-natural experiment in China

ABSTRACT Digital transformation (DT), government intervention (GI) and carbon emissions (CE) have always been the focus of academic attention, and arguments on the relationship amongst them exist. This study seeks to introduce the degree of political connection and government subsidies (GS) as GI into the relationship between DT and CE at the micro-level and aims to provide a new perspective for resolving previous arguments. By using a difference-in-differences model, the impact of DT on reducing CE is measured by taking a sample of 3925 observations from listed enterprises in China and dividing them according to the following degrees of political connection: none, moderate and high. Results show that DT is effective in reducing CE. Additionally, DT of enterprises with moderate political connections has had the greatest effect on reducing CE, followed by the effect of enterprises with high political connections. The effect of enterprises with no political connections is insignificant. If enterprises with a moderate or no political connections gains more GS, then the negative impact of DT on CE will be stronger. This study provides new evidence that DT reduces CE at the micro-level and presents a new perspective on reaching a consensus by introducing GS and the degrees of political connection.

Improved access and care through the implementation of virtual Hallway, a consultation platform in Nova Scotia: preliminary findings from a feasibility evaluation

BackgroundWhile previous studies have examined various platforms that enable providers to connect, Virtual Hallway (VH) stands out with its unique features. The value add is that this online platform connects primary care providers and specialists for synchronous phone-based conversations and aims to reduce referrals and enhance the quality of referrals. VH allows providers to easily log in, select the required specialty, book call times, receive reminders, and have calls documented, ensuring a high connection rate. In May 2022, the provincial health authority in Nova Scotia, a Canadian province, and VH initiated a feasibility study facilitated through the Health Innovation Hub in Nova Scotia. The goal was to enable primary care providers to connect with specialists, thereby reducing wait times and unnecessary referrals, and facilitating timely access to relevant clinical direction for patients. The current evaluation assessed utilization, value for money in economic analysis, and consultation experiences.MethodsThe study used post, cross-sectional, and cost-benefit study designs. We collected data through various methods, including administratively recorded utilization, theory-driven surveys, and cost data. Utilization was measured by the number of completed consults and the number of healthcare professionals using the VH platform. We analyzed the data using a combination of descriptive statistics and a cost-benefit analysis, which also involved conducting probabilistic sensitivity analysis.ResultsThe study found that approximately 84% of the VH consultations avoided needing in-person specialist referrals. The return on investment was 1.8 (95% CI: 0.8 to 3.0), indicating that the monetary value of the measurable benefits associated with VH exceeded the value of the resources invested. The provider experience survey revealed high satisfaction levels with VH across user groups, with 92% of specialists and 96% of primary care providers reporting being satisfied or highly satisfied with their experience. These positive indicators of provider experience were further supported by the fact that 97% of respondents agreed or strongly agreed that they intended to continue to use VH in their practice, and 97% of respondents agreed or strongly agreed that they would recommend VH to a colleague.ConclusionsThe study suggests that VH was well-received by users, with high levels of satisfaction reported and a reduced need for in-person referrals. It also represented value for money. Further research could explore how the availability of virtual health services can lead to reduced utilization of healthcare resources among different groups of patients.

Design and Performance Analysis of Windings Considering High Frequency Loss and Connection Mode of a Starter Generator

The starter generator is the key component of the aircraft’s starter generation system. A high power density, efficiency, and reliability are essential for an aircraft’s starter generator. The configuration of the windings is closely related to the performance of the starter generator. In this paper, the winding performance analysis and design are studied. Considering the skin effect, circulation effect, and proximity effect, a calculation model of winding loss under high-frequency operation is established. The motor performance under different winding connections is compared. Through a comprehensive comparison of starting performance, generation loss, and process performance differences, the optimum configuration of windings is identified. The performance of the starter generator including winding resistance, current, and no-load loss was tested on the prototype platform to verify the rationality and correctness of the analysis and design methods.

5G network performance using novel MIMO mixed FSO/MMW communication systems under pointing errors effect: test analysis using image transmission

Abstract Millimeter waves (MMW) enable high data rates over short distances; free-space optical (FSO) provides high-capacity optical wireless transmissions; and multiple-input multiple-output (MIMO) maximizes antenna utilization. These are the three leading technologies that work harmoniously to deliver 5G’s superior performance. This collaborative effort results in 5G’s ability to offer high connection capacities, low latency, and rapid speeds, creating new opportunities for industrial and internet of things applications. In this paper, the proposed system combines FSO links and MMW radio frequency (RF) links to enhance the performance of mixed FSO/RF systems. FSO experiences turbulence and pointing errors (PE), while MMW undergoes fading. Using both FSO and MMW provides diversity against channel fading. Furthermore, both the FSO and MMW links utilize MIMO technology to combat fading through spatial diversity. The FSO link is modeled with a Gamma-Gamma Turbulence model and PE. The MMW link is modeled with Rayleigh fading. By combining these two types of links with MIMO, the system can achieve improved performance compared to using either FSO or MMW alone. The dual nature of the system provides robustness against different types of channels fading effects. Overall, the goal is to enhance performance by capitalizing on the complementary channel characteristics of optical and RF links and exploiting MIMO’s spatial diversity benefits. In the present work, closed-form formulas accounting for the influence of PE are generated for the bit error rate (BER). This article also explores the MIMO mixed FSO/MMW system with multiple modulation techniques under various turbulence situations. The suggested system is ultimately verified by transmitting images with suitable fixed BER.

Design of Docking Interfaces for On-Orbit Assembly of Large Structures in Space

Considering the complexity of on-orbit assembly during space missions and the super-large size of space structures, this paper presents the design for a new type of docking interface with an androgynous body that exhibits a number of advantages, including high connection strength and a compact structure. The androgynous body has a conical guided symmetric design with a symmetry of 90°. The geometric design of the docking surface is described in detail in order to prove its advantages. Structural design was carried out using UG modeling as well as dynamic simulation using Recur Dyn to obtain the displacement coordinate curves of the docking port. The geometry of the docking port’s high docking misalignment tolerance was verified, and misalignment tolerance and lens splicing experiments were also performed. The docking port’s ability to be quickly connected or disconnected within a translation tolerance of 23.5 mm and a tilt tolerance of 24° was verified. This article provides a useful reference for space missions in terms of module docking and on-orbit assembly.

Research and Application of Flexible Fracturing Manifold in Volumetric fracturing

Abstract In order to solve the problems of high pressure pipe valves in Volumetrictric fracturing, such as large demand of high pressure pipe and valve parts, high pressure manifold for fracturing complex connection, fracturing pipeline connections are complex, long fracturing construction preparation period. The economy and timeliness of pipeline connection seriously affect the speed and efficiency of Volumetrictric fracturing operations. This paper designed and developed the high pressure flexible composite pipe and carried out its performance evaluation test. Combined with Volumetrictric fracturing operation conditions, supporting functional modular manifold system, overcome flexible pipeline and rigid pipeline fast connection technology, flexible fracturing manifold system was formed. Through the large-scale field application in the unconventional reservoir Volumetric fracturing field, The flexible fracturing manifold is compared with the conventional high-pressure pipe valve connection and the single pipe universal connection, the flexible fracturing manifold can reduce the use of high-pressure pipe valves by 1/3, increase the efficiency of fracturing manifold connection by 50%, and reduce the labor intensity by 50%, enables efficient, reduce high pressure manifold connection points by 70%. The timeliness and safety of fracturing manifold connections have been greatly improved. Flexible fracturing manifold fundamentally change the connection mode of Volumetrictric fracturing high-pressure manifold, and realizes the speed and efficiency of reservoir transformation.

EarthWorks: Zero waste 3D printed earthen formwork for shape-optimized, reinforced concrete construction

Rapid global urbanization is driving governments and builders to seek paradigm-shifting technologies to speed the construction of housing and infrastructure at a low economic and carbon cost. Here, we present a novel method for fabricating materially efficient, shape-optimized, code-compliant, reinforced concrete structures cast in directly recyclable 3D printed earth formwork, hereby referred to as EarthWorks. This research demonstrates the potential of zero waste, circular formwork that can be manufactured with construction waste soils directly on site. Methods are described for formwork design and toolpathing that accounts for hydrostatic pressure, conventional reinforcement, high accuracy connections, and the fabrication of complex, 3D-shaped geometry with continuous extrusion. In addition, the building design and performance potential of the EarthWorks method are assessed and compared to existing additive formwork technologies from a carbon perspective. Case studies are fabricated demonstrating cast-in-place, tilt-up, and on-site prefab methods to produce bespoke columns, beams, and frames designed to California building code.

Interannual Glacial Mass Changes in High Mountain Asia and Connections to Climate Variability

We use data from the Gravity Recovery and Climate Experiment and its Follow-On mission (GRACE/GRACE-FO) from April 2002 to December 2022 to analyze interannual glacial mass changes in High Mountain Asia (HMA) and its subregions and their driving factors. Glacial mass changes in the HMA subregions show clear regional characteristics. Interannual glacial mass changes in the HMA region are closely related to interannual oscillations of precipitation and temperature, and are also correlated with El Niño–Southern Oscillation (ENSO). Glacial mass changes in the regions (R1–R6) are dominated by precipitation, and ENSO affects interannual glacial mass changes mainly by affecting precipitation. In region (R7) and region (R8), the glacial mass changes are mainly controlled by temperature. ENSO also affects the interannual glacial mass changes by affecting interannual changes in temperature. The interannual glacial mass changes in regions (R9–R11) are jointly dominated by temperature and precipitation, and also related to ENSO. Another interesting finding of this study is that glacial mass changes in the western part of HMA (R1–R6) show a clear 6–7-year oscillation, strongly correlated with a similar oscillation in precipitation, while in the eastern part (R9–R11), a 2–3-year oscillation was found in both glacial mass change and precipitation, as well as temperature. These results verify the response of interannual HMA glacial mass changes to climate processes, crucial for understanding regional climate dynamics and sustainable water resource management.

How to choose mobile energy storage or fixed energy storage in high proportion renewable energy scenarios: Evidence in China

With the large-scale integration of renewable energy and changes in load characteristics, the power system is facing challenges of volatility and instability. Therefore, enhancing the safe and stable operation capability of the power system is an urgent problem that needs to be solved. Mobile energy storage can improve system flexibility, stability, and regional connectivity, and has the potential to serve as a supplement or even substitute for fixed energy storage in the future. However, there are few studies that comprehensively evaluate the operational performance and economy of fixed and mobile energy storage systems. To comprehensively evaluate the economic benefits of large-scale mobile energy storage systems, this paper constructs an overall horizontal cost model for energy storage systems that considers the power system and train transportation system. This model not only introduces the traditional concept of lifecycle cost of energy storage systems, but also considers the costs of traditional transmission lines and battery transportation. Secondly, to achieve simulation of large-scale mobile energy storage system planning and operation, this paper establishes a multi-region power planning and operation simulation (MPO) model and a battery transportation and logistics (BTL) model to accurately reflect the operation mode of fixed energy storage and mobile energy storage in the power system. Finally, taking the actual power grids and railway networks in Northeast and North China as case studies, this article provides an in-depth analysis of the technical, economic, and environmental performance of large fixed and mobile energy storage systems, and conducts a detailed comparison. The research results indicate that under high grid connection ratios (using 75% and 66% as examples), the overall cost of mobile energy storage systems continues to decrease to 1.42 CNY/kWh and 0.98 CNY/kWh. Compared to fixed energy storage at 5.45 CNY/kWh and 4.79 CNY/kWh, it has an absolute economic advantage and shows significant carbon reduction capabilities, reaching 241,800 to 1,394,600 tons. This discovery fully confirms the enormous potential and application value of mobile energy storage in high proportion renewable energy scenarios, providing strong technical support and economic analysis basis for the sustainable development of the power system.

A Study on the Construction of Brand Storytelling and the Emotional Connection of Generation Z

This study explores the characteristics and effects of Chow Tai Fook’s (CTF) brand storytelling, as well as the current situation and trend of Generation Z’s (Gen Z) emotional connection to the brand. The results show that CTF’s brand storytelling is unique and able to attract the attention of Gen Z. Gen Z has high awareness and emotional connection to CTF, and most of them highly recognize the importance of the background of the brand story. In terms of willingness to buy, a significant proportion of respondents believe that brand storytelling is one of the reasons why they buy jewelry and precious metal products, and that brand storytelling and creation are more appealing to consumers than simple sales pitches. Emotional resonance, uniqueness, quality assurance and social responsibility, and lifestyle leadership were all seen as important factors in terms of brand cultural characteristics. As for story construction, compelling plot construction and authentic and believable content presentation are the most significant attractions for Gen Z consumers, while all other aspects have significant impacts as well.

Development and Qualification of High Current Splices and Electrical Connections for the HL-LHC Magnets

Development and Qualification of High Current Splices and Electrical Connections for the HL-LHC Magnets

Effect of double-pulse frequency and post-weld heat treatment on microstructure and mechanical properties of metal-inert gas welded Al–Mg–Si alloy joints

The Al–Mg–Si alloy welded structure is widely used in aerospace, marine ship, automotive and other industries. However, the mechanical properties of welded joint were seriously weakened due to the microstructure coarsening and heat affected zone (HAZ) softening, making its service life decayed. In this paper, in order to enhance the mechanical properties of Al–Mg–Si alloy welded joint, a coupled method including double pulsed Metal Inert Gas (DP-MIG) welding technology and post-weld heat treatment (PWHT) were applied on the joining process of Al–Mg–Si alloy. With the increase of DP frequency from 2 Hz to 5 Hz, the average grain size of fusion zone decreased from 113.7 μm to 88.4 μm. And the tensile strength of welded joint was at the interval of 180∼190 MPa. After a suitable heat treatment (solution treatment at 530 °C for 2 h and aging treatment at 180 °C for 8 h), the tensile strength of welded joint increased to 318.3–333.8 MPa, which exceeds 90 % of the base metal (BM). Under the comprehensive effect of solid solution strengthening, fine grain strengthening, and precipitation strengthening, the mechanical properties of Al–Mg–Si alloy welded joint were significantly improved. And the research results in this paper can provide a research basis for high quality connection of Al–Mg–Si alloys.

Permutation mask: a combined gradient sparsification for federated learning

Large-scale distributed model training suffers from communication overheads due to frequent gradient updates transmitted between compute nodes. This situation gets even worse with training on mobile devices, which suffers from high latency, lower throughput and intermittent poor connections. Various recent works proposed to use quantisation or sparsification techniques to reduce the amount of data that need to be communicated, for instance Top-k sparsification. However, the Top-k sparsification is lack of the cooperation between nodes. In this paper, we present the permutation mask (Pmask), a novel gradient sparsification technique for distributed model training. To unite nodes and improve the convergence rate, Pmask employs non-zero average and combined gradients. The corresponding convergence property is also given. We have applied permutation mask to image classification task on Cifar10, mini-ImageNet and SVHN, and the experiments show that Pmask leads to a faster distributed training and improves the accuracy.

Microstructure formation mechanism and mechanical properties of super-thickness TC11 titanium alloy joint by electron beam welding and laser additive manufacturing hybrid connection technology

Advanced connection technology for extra-large/super-thickness titanium wrought components is urgent demand in aerospace manufacturing industries. For achieving high-performance titanium alloy super-thickness joint with a high connecting efficiency, a novelty concept of hybrid connection technology with electron-beam welding and subsequent laser additive connection is proposed. A super-thickness (200 mm) TC11 titanium alloy joint has been successfully prepared, and microstructure, tensile properties and fracture behavior of different regions in which are investigated. The results suggest that in stress-relieve heat treatment (SRT) condition, deformation and fracture of the joint are prone to occur in its low-strength wrought base material zone; after double annealing heat treatment (DAT), lamellar α phases in different zones of the joint become similar, associating with a higher fraction of fine secondary α phases in wrought base material zone. Therefore, the tensile properties of the joint are comparable to wrought properties. Although strength in different zones of hybrid connection joint is similar, ductility is not uniform and apparently lower in middle fusion zone due to grain heterogeneity. Overall, these findings indicate that hybrid connection can be one potential technology for fabricating high performance super-thickness titanium alloy joint with a high connection efficiency in engineering application fields.

Compression properties and energy absorption of Gyroid lattice cylindrical shells filled thin-walled tubes fabricated by selective laser melting

In recent years, lattice cylindrical shells (LCSs) based on the triply periodic minimal surfaces (TPMS) have been researched in the energy absorption (EA) field due to their distinctive mechanical properties. However, LCS structures will generate severe lateral expansion and localized fragmentation during compressive deformation, resulting in a significant decrease on compression performance. To further improve EA properties, Gyroid LCS filled thin-walled tubes (LCS-T) are proposed and produced by selective laser melting (SLM). In this work, the influence of the interaction (hollow thin-walled tubes + LCSs core) of the Gyroid LCS-T with different filling radii on the compressive properties and EA were investigated by the quasi-static compression experiments and finite element simulation systematically. The results showed that the Gyroid LCS-T based on AlMgScZr alloy fabricated by SLM had high connection strength and no obvious defects. The specific EA (SEA) of Gyroid LCS-T with radius of 3, 6, and 9 increased by 42.1%, 49.3%, and 53.3%, respectively, compared to thin-walled tubes. Compared to the sum of all components individually, the Gyroid LCS-T achieved superior performance in both compressive properties and EA by transferring stresses from the LCS interior to the thin-walled tube. Furthermore, the gradient design realized adjustment of the structural deformation and improved EA with about 1.24 times compared to uniform structure. This research offered visionary insights into designing energy-absorbing structures and optimizing parameters for LCS-T.

In-situ monitoring of an offshore wind turbine blade using acceleration and strain measurements

One of the most critical components of wind turbines is the blades. As blades are constantly exposed to weather and high loads, they can wear and become damaged. Performing in-situ continuous monitoring can help detect sudden damages and prevent further degradation, which is imperative to avoid economic losses and fatal accidents. However, monitoring a rotating rotor blade presents some challenges. One challenge is the consideration of lightning protection. Hence, a non-conductor measurement system must be used. Another challenge is system identification and modal tracking considering environmental and operational conditions (EOCs). Furthermore, vibration-based monitoring results from actual and operational rotor blades are scarce in the existing literature. This study centres on operational modal analysis (OMA) using covariance- driven stochastic subspace identification (SSI-COV) of an offshore wind turbine blade in operation employing eight months of data from fibre optic accelerometers (FOA) and fibre Bragg grating (FBG) strain gauges. The identification focuses on the first two bending modes in flapwise and edgewise directions and the first torsional mode. The study aims to determine which fibre optic sensor delivers better results. Furthermore, it addresses the effect of EOCs on the modal parameters, where system identification and modal tracking are discussed. It was found that tracked modes showed similar trends with respect to time, and a high connection was observed between wind speed, rotor speed, and pitch angle with frequency and damping. Additionally, acceleration and strain measurements deliver the same frequency and damping values. FBG better identified the first flapwise mode. On the other hand, FOA was superior in almost all other modes. This study points towards employing FOA for vibration-based monitoring of wind turbine blades using modal parameters.