bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Analytical Model for the Transverse Piezoresistive Response of Fiber-Reinforced Nano-Modified Polymers via an Electrical Concentric Cylinders Assemblage Approach
Authors: Ghazzawi Sultan M. , Tallman Tyler N. 
Published: November 2023

Abstract
Continuous fiber-reinforced composites exhibit complex failure mechanisms, often unapparent to the unaided eye. Using nanofiller modification to introduce self-sensing capabilities via the piezoresistive effect into these composites has been widely explored. However, to make meaningful predictions of the mechanical state of the composite, accurate piezoresistivity models are needed. Modeling efforts have largely focused on microscale piezoresistivity, often via utilizing computationally intensive resistor network models, which are limited to very small dimensions and consequently unsuitable in macroscale structural contexts. Furthermore, the role of the continuous fiber reinforcement has been widely overlooked; in other words, there has been little effort put into developing reliable analytical models for predicting conductivity changes in continuous fiber-matrix systems. To bridge this gap, this work proposes an analytical model predicting axial-strain induced transverse piezoresistivity in a nanofiller-modified polymer phase enveloping a continuous fiber reinforcement phase. An electrical concentric cylinders assemblage (ECCA) concept lies at the heart of this strategy. The model initiates with two concentric cylinders representing a reinforcing fiber surrounded by a nanofiller-modified conductive matrix. The system is homogenized to predict the transverse resistivity changes as a function of applied longitudinal strains and the constituent electro-mechanical properties. This is accomplished by imposing the concept of equal volumetric averages of current densities as well as utilizing existing tensor-based piezoresistivity relations for the nanofiller-modified matrix. The model studies transverse piezoresistive responses of CNF-epoxy composites with glass and conductive Kevlar 49 fibers at different volume fractions, and the outcomes will be compared to rule of mixtures predictions.
Nonlinear Dynamics of Two-Degree-of-Freedom Vortex-Induced Vibration Energy Harvester
Authors: Hu Guobiao , Tang Lihua , Wang Junlei , Li Xin , Liang Junrui 
Published: November 2023

Abstract
Vortex-induced vibrations (VIV) often occur in many engineering situations, such as offshore structures, large-span bridges, and fluid piping systems. Harnessing energy from VIV, on the one hand, can provide a sustainable power supply to the essential sensing devices for structural health monitoring; on the other hand, it can dissipate the vibration energy and help protect the structural integrity. This paper presents the dynamic analysis of a two-degree-of-freedom (2DOF) VIV piezoelectric energy harvester (PEH). The governing equations of the 2DOF VIV-PEH are developed by using the wake oscillator model to describe the aerodynamic force. The dynamic response of the 2DOF VIV-PEH is compared with that of a traditional one-degree-of-freedom (1DOF) counterpart. It is found that the 2DOF VIV-PEH can generate two lock-in regions for broadband energy harvesting. Further analysis shows that the 2DOF VIV-PEH undergoes in-phase and out-of-phase motions in the first and second lock-in regions, respectively. The fast Fourier transform (FFT) and modal analyses unveil that the two lock-in regions are related to and determined by the two resonances of the 2DOF VIV-PEH. Based on the understanding of the above fact, a parametric study is conducted to explore how to adjust the two resonances of the 2DOF VIV-PEH for customizing the two lock-in regions. Some design guidelines for tuning the system parameters are summarized according to the parametric study. Finally, the maximum power analysis is performed. Optimal resistances for obtaining the maximum power outputs are identified for the 2DOF VIV-PEH in different lock-in regions.
The Performance Investigation of Triboelectric Nanogenerator Based on Flow Induced Vibration by Applying Bluff Bodies With Different Cross Sections
Authors: Li Zhongjie , Yuan Yukun , Wu Hao , Zhang Di , Wang Min , Ding Jiheng 
Published: November 2023

Abstract
In this paper, we propose a non-streamlined solid-liquid triboelectric nanogenerator (TENG) designed to collect low-velocity flow energy using flow induced vibration (FIV) and the friction electrification effect. We investigate the influence of FIV on the lift and vibration frequency of various cross section of bluff bodies, including triangular prisms, pentagonal prisms, elliptical cylinders, and circle-triangular prisms, under different angles of attack (0°, 30°, 60°, 90°). Our study focuses on how the external structure’s motion characteristics affect the internal solid-liquid friction. The simulation results indicate that the periodic lift on the bluff body becomes asymmetric when the cross section shape is asymmetric relative to the direction of flow field motion. Moreover, the vibration frequency increases with the number of edges of the bluff body. In the case of an elliptical cross-section, the vortex in the tail is the weakest when the long axis of the ellipse is parallel to the flow direction, resulting in the lowest lift and highest vibration frequency. We also investigate the influence of the impact height of liquid on the inside wall of the harvester, and find that for various cross section of bluff bodies, the maximum position that the internal liquid level can reach during the shaking process is directly proportional to the frequency of vibration. Finally, we establish a mapping relationship between the output performance of the TENG and FIV to provide a parametric model for optimizing TENG performance.
A Theoretical and Experimental Analysis of the Aerodynamic Response of a Piezocomposite Ornithopter Wing
Authors: Katibeh Mohammad , Bilgen Onur 
Published: November 2023

Abstract
The mechanism-free ornithopter concept, also referred to as the solid-state ornithopter concept, has been previously proposed to utilize piezocomposite actuators to mimic flapping motion of an avian. In this concept, a set of Macro-Fiber Composite actuators are attached to a wing-shaped carbon fiber substrate, and the heaving and pitching type motion are generated through the strain induced by the actuators. In the proposed concepts, a large number of geometric and structural parameters determine the dynamic behavior and performance. Therefore, it is necessary to conduct multi-disciplinary design optimization to obtain the optimal configuration of the model parameters to achieve a feasible level of aerodynamic performance. The study of the fundamental aerodynamic characteristics of the solid-state ornithopter can be conducted using high-fidelity two-way fluid-structure interaction models; however, due to computational limits, these models are often not feasible for evaluating a large number of cases. It is possible to replace high-fidelity models with an approximate solution. In this paper, a low-fidelity model based on Theodorsen’s solution for unsteady two-dimensional airfoils under harmonic motion is developed. The heaving and pitching motion of the wing required for the approximate solution are obtained using a finite element model for the piezocomposite wing under harmonic motion. The lift force and pitching moment are obtained using the approximate solution by discretization of the wing. Furthermore, wind tunnel experiments are conducted on the solid-state ornithopter wing prototype to investigate the aerodynamic response. The experimental results are compared with the simulation results to evaluate the accuracy of the proposed model. The approximate solution has limitations due to neglecting the three-dimensional flow over the wing and the effects of aerodynamic loads on the heaving and pitching motions.
Exploring 6-Ply Twisted and Coiled Polymer Actuators With Active Cooling and Position Control
Authors: Singh Abhishek Pratap , Tadesse Yonas 
Published: November 2023

Abstract
Twisted and coiled polymer (TCP) actuators have gained attention for their high load carrying capacities in small and confined spaces, such as robotic arms to actuate fingers or wearable orthotic devices. There are many types of TCP actuators and one of them is constructed using silver-coated nylon thread in-house using simple fabrication process. However, their slow actuation speed limited the practical applications in robotics. Fast contraction of TCPs can be achieved by actuating at higher voltage, but cooling methods for fast removal of heat from the actuator is needed to quickly return to its resting position. In this paper, we present the behavior of 6-ply TCP actuators with active cooling, establish a model of the system, and formulate a position control algorithm for achieving rapid and precise control of these actuators. The findings indicated that active cooling of TCP actuators can substantially enhance their actuation speed, rendering them more appropriate for practical robotic applications.
Technology Demonstrator Platform for Fast-Switching Decoupled Antagonistic SMA Actuators
Authors: Gorges Tom , Molitor Philipp , Britz Rouven , Goergen Yannik , Motzki Paul 
Published: November 2023

Abstract
This work deals with the development of a descriptive and interactive demonstrator platform with a total of four different shape memory alloy (SMA) actuator systems. The motivation for this demonstrator development is to illustrate this new special decoupled antagonist system configuration, its capabilities of fast switching times and the variety in design. In total, two linear actuators and two rotary actuators are combined in a marble-run like setup. In this run, a ping-pong ball travels through different stations, only to be transported to the next station through the sequential activation of the actuation systems. One of the rotary actuators provides a 90° rotation in order to display the potential of an actuator in a production line. The second rotary actuator contains a bistable element to illustrate another type of energy efficient SMA actuator structure. The two linear actuators are very similar in their design, with one of them showing miniaturization potential of this mechanism e.g. for compact valve systems.
In all cases a quick back and forth movement of several hundred milliseconds is realized. For control of the actuators, a single circuit board is developed and PWM based activation strategy is used to account for the different electrical resistances of the various installed SMA wires in this demonstrator.
Fabrication of Parallel Compliant Mechanisms via Additive Manufacturing
Authors: Shah Divya , Berselli Giovanni , Parmiggiani Alberto 
Published: November 2023

Abstract
The manufacturing and assembly of small parallel mechanisms are often complex because of the required tolerances and high part count. The present work focuses on the use of additively manufactured compliant mechanisms to overcome some of these difficulties. As a reference, this work considers a recent work on a two degrees of freedom parallel orientational mechanism. Several aspects related to the design and manufacturing of this type of small-scale system are addressed by considering two implementations of the mechanism, one developed following a “traditional” approach with linkages and pin joints, and the other developed following a “flexible” approach using additively manufactured flexures. The two versions of the mechanism are finally compared to provide qualitative and quantitative indications of their motion precision and capacity to withstand loads.
Design of a Soft Underwater Gripper With SMA Actuation
Authors: Var Sezer C. S. , Jovanova Jovana 
Published: November 2023

Abstract
Underwater robot tasks pose many challenges for conventional robotic systems. The current rigid robots are limited in their adaptability to the environment and the objects to be manipulated. Soft grasping of objects offers advantages due to the flexibility when dealing with, for example, living organisms, random shaped objects, and coral reefs. Additionally, conventional robotic systems face difficulties when exploring the planet’s deep waters due to higher pressures and susceptibility of the often large amount of electronics to underwater conditions. Smart materials such as shape memory alloys can be more advantageous for the actuation of soft robotic underwater grippers because there is less need for complex electronic systems. Therefore, this project explores the use of smart materials for the actuation of a soft robotic underwater gripper. With this aim, three different gripper designs were made and evaluated. Various flexible materials, smart materials, 3D printing settings, numerous gripper configurations, and manufacturing methods are investigated. The gripper is intended to be a maintenance and inspection addon for an underwater autonomous vehicle.
Data-Driven Estimation of Bandgap Frequencies in Metastructures for Elastic Wave Absorption
Authors: Gosavi Hrishikesh , Malladi Vijaya V. N. Sriram 
Published: November 2023

Abstract
This study investigates the elastic wave absorption behavior of metastructures in the bandgap frequency region. The bandgap region is estimated using data-driven methods based on the Frequency Response Function (FRF) of the unit cell of the metastructure. To achieve this, the unit cell is discretized using 1-D finite bar elements, and the numerical FRFs are calculated to dynamically link multiple unit cells using Component Mode Synthesis (CMS). The location of the bandgap is determined through the FRF of the multi-unit cell structure, which is referred to as Dynamically Linked Element Grade Oscillators (D-LEGOs) due to the dynamic coupling between unit cells.
The study also estimates the dispersion relation of the structure from the mode shapes of the finite structure. This approach is validated through the estimation of the bandgap from dispersion relations calculated using the traditional Finite Element Method. This comprehensive and validated method provides a way to estimate the edge frequencies of the bandgap in metastructures. The findings of this study contribute to the development of new metastructure designs that can inhibit elastic wave propagation in specific frequency ranges. Such designs have potential applications in various industries, including aerospace, defense, and transportation. In conclusion, this study highlights the importance of understanding the dynamic behavior of metastructures in modern engineering and their impact on various industries.
Novel Pumping Mechanism for Heat Sinks With Fluid Medium Using Steady State Traveling Waves
Authors: Rajendran Krishnakumar , Gosavi Hrishikesh , Malladi Vijaya V. N. Sriram 
Published: November 2023

Abstract
The use of steady-state traveling waves as a novel pumping mechanism in liquid-cooled heat sinks offers a controlled and efficient method for fluid flow and heat removal without the need for an external fluid transfer pump. This experimental study demonstrates how traveling waves can be harnessed in a beam submerged in quiescent water using two force input methods, with the waves used to remove heat from a ceramic-based Positive Temperature Cofficient (PTC) heating element. The study analyzed the heating and cooling profiles of the heating element under two different conditions which are still water cooling and forced liquid convection cooling using steady-state traveling waves. The findings showed that a steady-state traveling wave could be an effective pumping mechanism for liquid-cooled heat sinks, resulting in lower maximum temperatures and equilibrium times than still-water cooling. These results suggest that optimizing the parameters like voltage and frequency could improve the performance of liquid-cooled heat sinks for various designs and operating conditions.
A Multi-Directional Low-Frequency Electromagnetic Energy Harvester
Authors: Law Nok Yin Christie , Tang Lihua 
Published: November 2023

Abstract
Low-frequency multi-directional vibrations pose one of the main challenges for energy harvesting to provide sustainable power for electronic devices in real applications. This work presents an energy harvester design that can covert low-frequency multi-directional vibrations to rotational motions and generate electricity for consumer electronic devices. With the implementation of a spring supported rotational electromagnetic transducer, the device can adapt to vibrations in any direction and achieve an average power of 1.14 mW when excited at 2.4 Hz and 0.2 g. A power management circuit is designed to regulate the output to an appropriate voltage and successfully provide the power for continuous operation of low-power electronics. For wireless sensors that demand high start-up power consumption, further improvement in power management is required to ensure the cold start of the device after enough energy is harvested and stored by the developed harvester.
Smart Structural Materials With Embedded Fiber Optic Sensors for Health Monitoring in Harsh Environments
Authors: Zhang Xinchang , Hua Zilong , Rufner Jorgen F. 
Published: November 2023

Abstract
Structural health monitoring is critical for components working in harsh environments to assessing their safety and integrity. This can be realized with advanced sensors, such as fiber optic sensors, embedded in these components. Recent studies have explored the use of ultrasonic additive manufacturing and laser-based additive manufacturing for fiber embedment. Fiber embedding using these techniques has been challenging for high-temperature materials commonly used in extreme environments, resulting in large gaps and voids around the embedded fiber. A good fiber-matrix bond is critical to guarantee free gas/liquid leaks as well as good temperature sensing and strain coupling. To this aim, this study proposed a novel fiber embedding technique using electric field-assisted sintering (EFAS). Sapphire fibers with a diameter of 125 μm and length of 55 mm were placed in SS316L powder, which was subsequently sintered using EFAS. To optimize the processing parameters for fiber embedment, a parametric study was scoped. The as-fabricated samples were first examined using optical transmission testing to inspect fiber integrity. After that, the samples were cross-sectioned for microscopy analysis to evaluate the quality of bond between the embedded fiber and the matrix. The density, microstructure, and hardness of the sintered SS316L were also studied to optimize EFAS parameters. The result shows that intact sapphire fibers can be embedded in high-density SS316L with good metallurgical bonds using the optimized EFAS parameters. Optical transmission inspection demonstrates the successful transmission of light through the embedded fibers.
Host translation machinery is not a barrier to phages that interact with both CPR and non-CPR bacteria
Authors: Liu Jett , Jaffe Alexander L. , Chen LinXing , Bor Batbileg , Banfield Jillian F. 
Published: November 2023

ABSTRACT
Within human microbiomes, Gracilibacteria, Absconditabacteria, and Saccharibacteria, members of Candidate Phyla Radiation (CPR), are increasingly correlated with human oral health and disease. We profiled the diversity of CRISPR-Cas systems in the genomes of these bacteria and sought phages that are capable of infecting them by matching their spacer inventories to large phage sequence databases. Gracilibacteria and Absconditabacteria recode the typical TGA stop codon to glycine and are putatively infected by phages that share their host’s alternate genetic code. Unexpectedly, however, other predicted phages of Gracilibacteria and Absconditabacteria do not use an alternative genetic code. Some of these phages may infect both alternatively coded CPR bacteria and standard-coded bacteria. These phages typically rely on other stop codons besides TGA and thus should be capable of producing viable gene products in either bacterial host type. By avoiding the acquisition of in-frame stop codons, these phages may have a broadened host range. Interestingly, we additionally predict that some phages of Saccharibacteria are targeted by spacers encoded in Actinobacteria, a phylum that includes known hosts for episymbiotic Saccharibacteria.

IMPORTANCE
Here, we profiled putative phages of Saccharibacteria, which are of particular importance as Saccharibacteria influence some human oral diseases. We additionally profiled putative phages of Gracilibacteria and Absconditabacteria, two Candidate Phyla Radiation (CPR) lineages of interest given their use of an alternative genetic code. Among the phages identified in this study, some are targeted by spacers from both CPR and non-CPR bacteria and others by both bacteria that use the standard genetic code as well as bacteria that use an alternative genetic code. These findings represent new insights into possible phage replication strategies and have relevance for phage therapies that seek to manipulate microbiomes containing CPR bacteria.
Protocol for the EACH trial: a multicentre phase II study evaluating the safety and antitumour activity of the combination of avelumab, an anti-PD-L1 agent, and cetuximab, as any line treatment for patients with recurrent/metastatic head and neck squamous cell cancer (HNSCC) in the UK
Authors: Ng Kenrick , Metcalf Rob , Sacco Joseph , Kong Anthony , Wheeler Graham , Forsyth Sharon , Bhat Reshma , Ward Joseph , Ensell Leah , Lowe Helen , Spanswick Victoria , Hartley John , White Laura , Lloyd-Dehler Elizabeth , Forster Martin 
Published: November 2023

IntroductionHead and neck cancer is the eighth most common cancer in the UK. Current standard of care treatment for patients with recurrent/metastatic squamous cell head and neck carcinoma (HNSCC) is platinum-based chemotherapy combined with the anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibody, cetuximab. However, most patients will have poor median overall survival (OS) of 6–9 months despite treatment. HNSCC tumours exhibit an immune landscape poised to respond to immunotherapeutic approaches, with most tumours expressing the immunosuppressive receptor programmed death-ligand 1 (PD-L1). We undertook the current study to determine the safety and efficacy of avelumab, a monoclonal antibody targeting the interaction between PD-L1 and its receptor on cytotoxic T-cells, in combination with cetuximab.Methods and analysisThis is a multi-centre, single-arm dose de-escalation phase II safety and efficacy study of avelumab combined with cetuximab; the study was to progress to a randomised phase II trial, however, the study will now complete after the safety run-in component. Up to 16 participants with histologically/cytologically recurrent/metastatic squamous cell carcinoma (including HNSCC) who have not received cetuximab previously will be recruited. All patients will receive 10 mg/kg avelumab and cetuximab (500, 400 or 300 mg/m2depending on the cohort open at time of registration) on days 1 and 15 of 4-week cycles for up to 1 year, (avelumab not given cycle 1 day 1). A modified continual reassessment method will be used to determine dose de-escalation. The primary objective is to establish the safety of the combination and to determine the optimum dose of cetuximab. Secondary objectives include assessing evidence of antitumour activity by evaluating response rates and disease control rates at 6 and 12 months as well as progression-free and OS.Ethics and disseminationApproval granted by City and East REC (18/LO/0021). Findings will be published in peer-reviewed journals and disseminated at conferences.Trial registration numberNCT03494322.