bluuebunny/crossref_metadata_2025 huggingface dataset:
Systematic Thermo-Mechanical Validation of Numerous Tensile-Loaded NiTi Wire Bundles Used for Elastocaloric Heating and Cooling
Authors: Kirsch Susanne-Marie , Welsch Felix , Ehl Lukas , Louia Franziska , Seelecke Stefan , Motzki Paul
Published: November 2023

Nickel-Titanium (NiTi)-based shape memory alloys (SMAs) enable new sustainable and environmentally friendly solid-state heating and cooling technologies. Elastocaloric (EC) heat pump systems exploit superelastic SMAs as a non-volatile, inflammable, and non-global-warming refrigerant, in contrast to the well-established vapor compression technology. The high specific latent heat released or absorbed during mechanical loading or unloading of the SMA material leads to a high temperature change in the material. As a result of the small required work input to induce the phase transformation, a high coefficient of performance (COP) can be achieved by this technology. The potential of these alloys can be exploited through an adequate thermodynamic cycle, efficient mechanical system design, and choice of suited EC materials.

A fully functional continuous operating EC heat pump system based on SMA was developed and realized recently. The EC heat pump system comprises 24 thin wire bundles of 30 wire segments in one bundle. To assist the design process of an optimized device with given performance and efficiency requirements, the air-cooling behavior of single wires and simple bundle arrangement has been analyzed, and intensive parameter studies on different airflow rates have been performed.

Regarding validating the EC heat pump system, a reproducible manufacturing process is presented for the first time, which supports the installation of at least 720 SMA segments in the same thermo-mechanical state.

This work introduces the bundle fabrication process for the first time and validates it by comparing the key thermo-mechanical values of 135 SMA bundles.
The Effects of Electroplating on the Mechanical Properties of Additively Manufactured Structures
Authors: Simonson Kevin , Vyshniakova Kateryna , Nawrocki Robert , El-Shahat Adel , Newell Brittany
Published: November 2023

3D printing, using fused deposition modeling (FDM) has become a staple in the prototyping process because it allows engineers and designers to manufacture parts within a matter of hours instead of days. FDM printing works by melting and extruding plastic filament through a heated nozzle to build a 3D object layer by layer. However, due to the nature of the additive process, parts often fail when placed under loads that they might be subjected to during testing; especially when the loads are applied to the specimen perpendicular to the layer lines. These failures often slow down or halt the iterative engineering process. This work aims to explore strengthening 3D printed parts using an electroplating process typically used to add conductive properties to the plastic material. Tensile testing dog bones that comply with ASTM D638 were printed using an off-the-shelf FDM printer. Specimens were printed parallel to the build plate, at a 45-degree angle from the build plate, as well as perpendicular to the build plate using both non-conductive Polylactic Acid (PLA) filament as well as conductive PLA. Specimens printed in the non-conductive PLA were manually painted with a conductive paint prior to electroplating. Conductivity tests were completed on the specimens before the electroplating process to study its effect on the process. The printed specimens were then subjected to an abrasive sanding process to aid in adhesion of the thin metal layer desired followed by a cleaning in distilled water. The electroplating process requires submerging the specimen to be electroplated as well as the desired metal in an electrolyte solution for an extended period. The specimens will act as an anode and be wired to the negative terminal of a power supply while the desired metal will act as the cathode wired to the positive terminal. Using a single column tensile tester, the specimens were subjected to the testing method provided in ASTM D638 to find the maximum load at failure for all the samples. A statistical analysis was conducted and found that difference of tensile strengths existed between the electroplated and non-electroplated parts where the electroplated parts were on average 20% weaker. While electroplating did not strengthen the 3D printed parts it did add conductive properties to them which gives designers more options when that is a property desired.
Nebula: A Flexible, Solid-State Swimming Robot Enabled by HASEL Actuators
Authors: Hess Isabel , Musgrave Patrick
Published: November 2023

After millions of years of evolution, ocean creatures have mastered the underwater environment. In human interactions with the underwater world, unmanned underwater vehicles (UUVs) are needed for applications where human divers are impractical or at great risk such as exploration of remote locations or the deep ocean. Current propeller-driven UUVs stand to gain greater efficiency and maneuverability by mimicking underwater creatures. Biological fish outperform the state-of-the-art bio-inspired UUVs, but it has been shown in hydrofoil literature that tailoring chordwise flexibility can improve swimming performance across several metrics. In this paper we aim to integrate chordwise flexibility and integrated soft actuators to demonstrate a soft robotic propulsor which better mimics the structure and capability of fish.

Inspired by cartilaginous body-and-caudal-fin (BCF) fishes like sharks, we built a soft robotic fish from compliant components with embedded smart actuators. The robot’s body is made of a 3D printed rubber skeleton and electro-hydraulic contracting-pouch actuators embedded in compliant silicone. The actuators used were hydraulically-amplified, self-healing electrostatic (HASEL) artificial muscles placed in an antagonistic configuration across the spine to produce lateral body contractions. We tailored the stiffness distribution of the body to passively induce BCF swimming kinematics at the caudal fin in response to actuator contractions in the main body. In this paper, the design and fabrication of the soft robot is described and its underwater structural dynamics are characterized with experimental testing in quiescent water. Full-body high speed videos of the robotic fish were taken at varying actuator input voltage and frequency to quantify its dynamic response. We show that the robot’s compliant body deforms like a biological fish and is capable of tail-beat speeds up to 73 mm/s. This flexible, joint-less design with embedded actuation is a step toward fieldable, lifelike bio-inspired UUVs for the future of underwater robotics.
Classifying Soil Saturation Levels Using a Network of UAV-Deployed Smart Penetrometers
Authors: Chowdhury Puja , Satme Joud N. , Yount Ryan , Downey Austin R. J. , Khan Sadik , Imran Jasim , Micheli Laura
Published: November 2023

Levees are built to safeguard human lives, essential infrastructure, and farmland. However, failure of levees can have catastrophic impacts due to a fast rate of inundation in areas protected by levees. Earthen levees are prone to failure due to excessive moisture content that reduces the shear strength of the soil. The use of levee monitoring systems has demonstrated the ability to reduce the likelihood of failure by creating maps that depict the saturation levels of the surface of the levee, both in terms of space and time. By utilizing extensive sensor networks to continuously monitor these geo-infrastructure systems, the structural deterioration attributed to changing climate can be studied. Measuring environmental parameters surrounding such structures provides insight into the potential stressors that cause structural failure. Steps can then be taken to mitigate those effects on the levees and maintain structural integrity. However, the massive scale of levees makes it difficult to monitor with conventional wired sensors. This paper presents a preliminary investigation into the development and validation of UAV-deployable smart sensing spikes for soil conductivity levels in levees, which is a measurement modality for determining soil saturation levels. For this work, Gaussian process regression (also known as kriging) is used to model the soil saturation levels between sensing spikes obtaining a continuous moisture map of the levees. The expanded data is then categorized using a clustering-based machine learning approach with conductivity data from sensing spikes as model inputs. The machine learning model output is sorted into three categories: dry, partially saturated, and saturated soil. The findings of a laboratory study are presented, and the implications of the raw and expanded data are discussed. This work will aid in predicting potential levee failure risks and maintenance requirements based on the analysis of the soil conditions using a network of smart sensing spikes.
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

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

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

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

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

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

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

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

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

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

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

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

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

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.
Reentrant Proximity-Induced Superconductivity for GeTe Semimetal
Authors: Esin V. D. , Kazmin D. Yu. , Barash Yu. S. , Timonina A. V. , Kolesnikov N. N. , Deviatov E. V.
Published: November 2023

We experimentally investigate charge transport in In–GeTe and In–GeTe–In proximity devices, which are formed as junctions between superconducting indium leads and thick single crystal flakes of α-GeTe topological semimetal. We observe nonmonotonic effects of the applied external magnetic field, including reentrant superconductivity in In–GeTe–In Josephson junctions: supercurrent reappears at some finite magnetic field. For a single In–GeTe Andreev junction, the superconducting gap is partially suppressed in zero magnetic field, while the gap is increased nearly to the bulk value for some finite field before its full suppression. We discuss possible reasons for the results obtained, taking into account spin polarization of Fermi arc surface states in topological semimetal $$\alpha $$-GeTe with a strong spin–orbit coupling. In particular, the zero-field surface state spin polarization partially suppresses the superconductivity, while it is recovered due to the modified spin-split surface state configuration in finite fields. As an alternative possible scenario, the transition into the Fulde–Ferrell–Larkin–Ovchinnikov state is discussed. However, the role of strong spin–orbit coupling in forming the nonmonotonic behavior has not been analyzed for heterostructures in the Fulde–Ferrell–Larkin–Ovchinnikov state, which is crucial for junctions involving GeTe topological semimetal.
Methylphenidate-associated chest pain in a child
Authors: Masiran Ruziana , Ilias Mohamad Nizam Adha , Yubbu Putri
Published: November 2023

A young child was diagnosed with autism spectrum disorder with comorbid attention-deficit/hyperactivity disorder. His hyperactivity, impulsivity and absence of awareness towards danger increased his risk of harm and hence methylphenidate was indicated. Unfortunately, he developed chest pain eight months after the treatment initiation. We then stopped the stimulant and changed his treatment to atomoxetine, after which he no longer had chest pain. In the following illustrated case, we will discuss the cardiac side effect of methylphenidate.
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

Introduction

Head 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 analysis

This 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 dissemination

Approval granted by City and East REC (18/LO/0021). Findings will be published in peer-reviewed journals and disseminated at conferences.

Trial registration number

NCT03494322.
Efficacy of a modified twin block appliance compared with the traditional twin block appliance in children with hyperdivergent mandibular retrognathia: protocol for a single-centre, single-blind, randomised controlled trial
Authors: Liu Anqi , Zhang Wei , Zhang Weihua , Shi Shuangshuang , Chen Zhuoyue , Liu Yuehua , Lu Yun
Published: November 2023

Introduction

Compensatory mouth breathing, caused by nasopharyngeal obstructive diseases, is the main cause of hyperdivergent mandibular retrognathia in children. Such deformities require effective growth guidance before pubertal growth peaks. The traditional mandibular advancement device, twin block (TB), can guide the forward development of the mandible. However, the side effect of increasing the vertical dimension of the lower facial third, worsens the facial profile of children with divergent growth trends. To solve this problem, a modified TB (LLTB) appliance was designed to control the vertical dimension by intruding incisors and inhibiting the elongation of posterior teeth during the advancement of the mandible, which could avoid the side effects of traditional appliances and effectively guide the growth of the mandible in a normal direction.

Methods and analysis

The study was designed as a single-centre, single-blind, randomised, parallel controlled trial. We aim to enrol 60 children aged 9–14 years with hyperdivergent skeletal class II malocclusion, using a 1:1 allocation ratio. The participants were will be randomly assigned to receive either the TB or LLTB treatment. The primary outcome will be a change in the angle of the mandibular plane relative to the anterior cranial base. The secondary outcomes will include changes in the sagittal maxillomandibular relation, occlusal plane, facial height, morphology of the mandible and upper airway width. Safety endpoints will also be evaluated.

Ethics and dissemination

Ethical approval was obtained from the ethics committee of Shanghai Stomatological Hospital. Both participants and their guardians will be fully informed of the study and sign an informed consent form before participating in the trial. The results will be publicly available in peer-reviewed scientific journals.

Trial registration number

ChiCTR2000035882.
Assessment of tannery sludge additions on physico-mechanical properties of clay bricks
Authors: Venkatesh G. , Krishnaiah S. , Ramesh G.
Published: November 2023

The present study explores the partial replacement of clay by the addition of tannery sludge (TS) and glass in brick preparation. Bricks were prepared with varying weight percentages of TS (9%, 18%, and 27%) along with glass powder (10%) and fired at different temperatures (900, 950, and 1000 °C). Water absorption, compressive strength, weight loss on ignition, volumetric shrinkage, and bulk density of the bricks were found to be in the range of 12.3%–16.8%, 2.3–4.5 MPa, 4%–13.8%, 6%–11%, and 1600–1850 kg/m3, respectively. Heavy metal leaching was observed to be within the limits of United States Environmental Protection Agency 1311 for the prepared bricks. The addition of TS resulted in a decrease of physical and mechanical properties of the bricks due to the decomposition of organic and inorganic compounds. However, the presence of glass powder compensates for the effect of TS by fusion and densification process. The results indicate that hybrid addition of TS and glass can partially replace clay in brick production and effectively immobilize heavy metals.
Thermodynamics of higher dimensional charged black holes: nonperturbative study
Authors: Malekian A. , Kokabi K. , Pourhassan B.
Published: November 2023

In this paper, we consider higher dimensional charged black holes to study nonperturbative corrected thermodynamics. This correction is dominant when the black hole size decreases due to the Hawking radiation. The nonperturbative correction on the black hole entropy is proportional to the exponential of the original entropy with a negative sign. We calculate some thermodynamics quantities such as the internal Helmholtz free energies, and obtain the effect of the exponential correction. We study the first law of thermodynamics and investigate how it satisfies. We also study the stability of the black hole through specific heat analysis and investigate the possible phase transition. We find a second-order phase transition that is interpreted as the unstable/stable phase transition. Then, we find a first-order phase transition that makes it unstable. Hence, the final stage of the Reissner–Nordström black holes may be an unstable phase, which means that black hole evaporation at the quantum scale. It may be a cause that we never find a black hole in accelerators.
Inexpensive polynomial-degree-robust equilibrated flux a posteriori estimates for isogeometric analysis
Authors: Gantner Gregor , Vohralík Martin
Published: November 2023

In this paper, we consider isogeometric discretizations of the Poisson model problem, focusing on high polynomial degrees and strong hierarchical refinements. We derive a posteriori error estimates by equilibrated fluxes, i.e. vector-valued mapped piecewise polynomials lying in the [Formula: see text] space which appropriately approximate the desired divergence constraint. Our estimates are constant-free in the leading term, locally efficient, and robust with respect to the polynomial degree. They are also robust with respect to the number of hanging nodes arising in adaptive mesh refinement employing hierarchical B-splines, though not with respect to the smoothness and support overlaps. Two partitions of unity are designed, one with larger supports corresponding to the mapped splines, and one with small supports corresponding to mapped piecewise multilinear finite element hat basis functions. The equilibration is only performed on the small supports, avoiding the higher computational price of equilibration on the large supports or even the solution of a global system. Thus, the derived estimates are also as inexpensive as possible. An abstract framework for such a setting is developed, whose application to a specific situation only requests a verification of a few clearly identified assumptions. Numerical experiments illustrate the theoretical developments.
Software Effort Estimation Based on Ensemble Extreme Gradient Boosting Algorithm and Modified Jaya Optimization Algorithm
Authors: Kumar Beesetti Kiran , Bilgaiyan Saurabh , Mishra Bhabani Shankar Prasad
Published: November 2023

Software development effort estimation is regarded as a crucial activity for managing project cost, time, and quality, as well as for the software development life cycle. As a result, proper estimating is crucial to the success of projects and to lower risks. Software effort estimation has drawn much research interest recently and has become a problem for the software industry. When results are inaccurate, an effort may be over- or under-estimated, which can disastrously affect project resources. In the sector, machine learning methods are becoming more and more prominent. Therefore, in this paper, we propose a Modified Jaya algorithm to improve the effectiveness of the estimated model; Modified JOA selects the ideal subset of components from an extensive feature collection. Then, the ensemble machine learning-based Enhanced Extreme gradient boosting algorithm and Ensemble Learning machine approach are employed to estimate the software effort. On the PROMISE SDEE repository, the proposed methodologies are empirically assessed. In this approach, applying machine learning techniques to the effort estimation process increases the likelihood that the time and cost estimates will be accurate. The proposed approach yields a greater performance. The key benefit of this approach is that it lowers the computational cost. This approach can also inspire the development of a tool that could reliably, effectively, and accurately estimate the effort required to complete different software projects.
Teaching Ethics in Computing: A Systematic Literature Review of ACM Computer Science Education Publications
Authors: Brown Noelle , Xie Benjamin , Sarder Ella , Fiesler Casey , Wiese Eliane S.
Published: November 2023

The computing education research community now has at least 40 years of published research on teaching ethics in higher education. To examine the state of our field, we present a systematic literature review of papers in the Association for Computing Machinery computing education venues that describe teaching ethics in higher-education computing courses. Our review spans all papers published to SIGCSE, ICER, ITiCSE, CompEd, Koli Calling, and TOCE venues through 2022, with 100 papers fulfilling our inclusion criteria. Overall, we found a wide variety in content, teaching strategies, challenges, and recommendations. The majority of the papers did not articulate a conception of “ethics,” and those that did used many different conceptions, from broadly applicable ethical theories to social impact to specific computing application areas (e.g., data privacy and hacking). Instructors used many different pedagogical strategies (e.g., discussions, lectures, assignments) and formats (e.g., stand-alone courses, incorporated within a technical course). Many papers identified measuring student knowledge as a particular challenge, and 59% of papers included mention of assessments or grading. Of the 69% of papers that evaluated their ethics instruction, most used student self-report surveys, course evaluations, and instructor reflections. While many papers included calls for more ethics content in computing, specific recommendations were rarely broadly applicable, preventing a synthesis of guidelines. To continue building on the last 40 years of research and move toward a set of best practices for teaching ethics in computing, our community should delineate our varied conceptions of ethics, examine which teaching strategies are best suited for each, and explore how to measure student learning.
Optimal Design of a Six‐Dimensional Force Sensor with Three‐Beam Structure
Authors: Chen Xiliang , Wang Zhiqiang , Xie Zhengyu , Li Ning , Sun Yiwen
Published: November 2023

A six‐dimensional force sensor with a three‐beam structure was designed, and its strain and stress distribution under various load conditions were analyzed based on finite element simulation technology. According to the strain distribution, the Wheatstone bridge scheme of the sensor is designed, and the output voltage and sensitivity formulas in each direction are deduced. The optimal patch location was determined according to the strain distribution on the centerline of the strain beam. Finally, the size parameters of the elastic body were optimized based on the response surface method and multiobjective genetic algorithm, which greatly improved the sensitivity of the sensor in all directions. It can provide a useful guidance for the optimal design of the six‐dimensional force sensor with a three‐beam structure.
Identification of Microbial Populations Present in Agricultural and Nonarable Soils in the Talas Valley, Northern Kyrgyzstan, in Autumn
Authors: Doolotkeldieva Tinatin , Bobusheva Saykal , Konurbaeva Mahabat
Published: November 2023

Soil bacterial and fungal communities were investigated in relation to soil type and farm management practices after vegetation harvesting in autumn. Soils from fields cultivated with Phaseolus vulgaris (bean) and Pyrus comminus (pear) and nonarable, natural areas were studied. Microbial diversity was analysed using cultivation-dependent methods (isolation of pure cultures) and cultivation-independent methods (direct extraction of DNA from soil, followed by PCR amplification of the 16S rRNA and 18S rRNA genes). The use of cultivation-dependent methods revealed that there were no differences in the biodiversity of the soil bacterial and fungal communities between fields cultivated with bean plants and pear trees. However, the use of cultivation-independent methods showed that there were clear soil and crop type-specific effects on the composition of the soil bacterial and fungal communities. The density of the bacterial population was two times higher in northern mountain-valley serozem (NMVS) soil samples than in light chestnut (LC) soil samples. In contrast, the densities of the fungal communities were almost equal in the studied soil types. The density of the actinomycetes community was almost two times higher in LC soil than in NMVS soil under bean plants. The Shannon index values showed that the bacterial biodiversity in the NMVS soil samples was greater than that in the LC soil samples. Soils under fallow appeared to have diverse bacterial communities that mainly consisted of local autochthonous microflora and a small amount of zymogenic microflora (since fresh plant residue does not enter the soil). The Shannon index results revealed two interesting facts: (1) the soil bacterial community was highly diverse in soils that supported bean plants and (2) the soil fungal biodiversity was high under pear trees in both soil types.