bluuebunny/crossref_metadata_2025_split huggingface dataset:
An orthogonal matching pursuit optimization method for solving minimum‐monitor‐unit problems: Applications to proton IMPT, ARC and FLASH
Authors: Zhu Ya‐Nan , Zhang Xiaoqun , Lin Yuting , Lominska Chris , Gao Hao 
Published: July 2023

AbstractBackgroundThe intensities (i.e., number of protons in monitor unit [MU]) of deliverable proton spots need to be either zero or meet a minimum‐MU (MMU) threshold, which is a nonconvex problem. Since the dose rate is proportionally associated with the MMU threshold, higher‐dose‐rate proton radiation therapy (RT) (e.g., efficient intensity modulated proton therapy (IMPT) and ARC proton therapy, and high‐dose‐rate‐induced FLASH effect needs to solve the MMU problem with larger MMU threshold, which however makes the nonconvex problem more difficult to solve.PurposeThis work will develop a more effective optimization method based on orthogonal matching pursuit (OMP) for solving the MMU problem with large MMU thresholds, compared to state‐of‐the‐art methods, such as alternating direction method of multipliers (ADMM), proximal gradient descent method (PGD), or stochastic coordinate descent method (SCD).MethodsThe new method consists of two essential components. First, the iterative convex relaxation (ICR) method is used to determine the active sets for dose‐volume planning constraints and decouple the MMU constraint from the rest. Second, a modified OMP optimization algorithm is used to handle the MMU constraint: the non‐zero spots are greedily selected via OMP to form the solution set to be optimized, and then a convex constrained subproblem is formed and can be conveniently solved to optimize the spot weights restricted to this solution set via OMP. During this iterative process, the new non‐zero spots localized via OMP will be adaptively added to or removed from the optimization objective.ResultsThe new method via OMP is validated in comparison with ADMM, PGD and SCD for high‐dose‐rate IMPT, ARC, and FLASH problems of large MMU thresholds, and the results suggest that OMP substantially improved the plan quality from PGD, ADMM and SCD in terms of both target dose conformality (e.g., quantified by max target dose and conformity index) and normal tissue sparing (e.g., mean and max dose). For example, in the brain case, the max target dose for IMPT/ARC/FLASH was 368.0%/358.3%/283.4% respectively for PGD, 154.4%/179.8%/150.0% for ADMM, 134.5%/130.4%/123.0% for SCD, while it was <120% in all scenarios for OMP; compared to PGD/ADMM/SCD, OMP improved the conformity index from 0.42/0.52/0.33 to 0.65 for IMPT and 0.46/0.60/0.61 to 0.83 for ARC.ConclusionsA new OMP‐based optimization algorithm is developed to solve the MMU problems with large MMU thresholds, and validated using examples of IMPT, ARC, and FLASH with substantially improved plan quality from ADMM, PGD, and SCD.
Band structures analysis of fluid–solid phononic crystals using wavelet‐based boundary element method and frequency‐independent fundamental solutions
Authors: Wei Qi , Xiang Jiawei , Zhu Weiping , Hu Hongjiu 
Published: July 2023

AbstractA novel method of combination of wavelet‐based boundary element method (WBEM) with frequency‐independent fundamental solutions is proposed to determine the band structures of fluid–solid phononic crystals (PCs) with square and triangular lattices. Integral equations established are based on the frequency‐independent fundamental solutions, which can avoid nonlinear eigenvalue problems and reduce computing time. Domain integral terms arising from the use of frequency‐independent fundamental solutions are handled with the radial integration method (RIM) and dual reciprocity method (DRM), respectively. The results show the lower precision in high frequency domain of using RIM to handle domain integral terms than that of using DRM, which can be solved by increasing Gauss point. The B‐spline wavelet on the interval and wavelet coefficients are applied to approximate the physical boundary conditions. It is proved that coupling conditions between matrix and scatterers and Bloch theorem are also applicable to wavelet coefficients. Some small matrix entries generated by wavelet vanishing moment characteristics are truncated by the provided matrix compression technique, and the influence of compressed matrices on the results is studied. Furthermore, the final Eigen equations constructed are modified to avoid numerical instability. Some examples are provided to demonstrate the accuracy and efficiency of the proposed method.
Studies of optical, photophysical, and thermal properties of poly(paraphenylenevinylene) (PPV) polymers with symmetric alkoxy side‐chain lengths for potential application in electronic devices
Authors: Zengin Huseyin , Ozer Ahmet , Zengin Gulay 
Published: July 2023

AbstractOptical, photophysical, and thermal properties of poly(paraphenylenevinylene) (PPV) derivatives of various symmetric alkoxyl substituents were studied with UV–vis and photoluminescence spectroscopy. Molar absorptivity coefficients of the symmetric monomers increased compared to that of hydroquinone and its derivatives. The symmetric polymers exhibited photoluminescence quantum yields in the range of 32%–39% and excited‐state lifetimes of 3.01–3.61 ns. The emission energy values for the calculated band gaps were in the range of 2.16–2.12 eV for the symmetric polymers. The photoluminescent characteristics of these compounds may show great potential in improving the emitting layers of electronic devices. The thermal behavior and heat changes of the symmetric dialkyl PPV polymers were monitored by TGA and DSC. Glass transition temperatures (Tg) for these polymers were observed as being in range of 67–108°C. The heat values of the symmetric dialkyl PPV polymers were found to be in range 220.41–599.98 J/g, and the entropy values of symmetric dialkyl PPV polymers were determined to be in range 0.567–1.754 J/ g °C.Highlights• Symmetric poly(phenylene vinylene) (PPV) derivatives were prepared.• UV–vis spectroscopy was used for optical absorption studies.• Photophysical properties were examined by photoluminescence spectroscopy.• TGA was used for the thermal behavior of symmetric dialkyl PPV polymers.• Heat changes of symmetric dialkyl PPV polymers were investigated by DSC.
Radiation effects on Kevlar fibers through high energy electron beam
Authors: Chen Wentao , Qi Wei , Du Jifu , Zhao Long 
Published: July 2023

AbstractThe Kevlar fibers were irradiated at up to 2500 kGy using a 10 MeV electron accelerator. The effects of radiation on the Kevlar fibers were evaluated in detail. The main structure, crystal structure, and thermal transition temperature of the fibers remained unchanged after electron beam radiation. The mechanical properties of the fibers decreased significantly when the absorbed dose reached 2000 kGy. In addition, viscosity tests revealed that electron beam radiation could damage the long polymer chains of the fibers. The FTIR results showed that the intensity of the CN bond decreased depending on the absorbed dose, indicating that CN bonds may be the degradation site of Kevlar fibers. This work provides a comprehensive radiation resistance evaluation for Kevlar fibers and thus offers some fundamental data for the application of Kevlar fibers in extreme environments.
CBP60‐DB: An AlphaFold‐predicted plant kingdom‐wide database of the CALMODULIN‐BINDING PROTEIN 60 protein family with a novel structural clustering algorithm
Authors: Amani Keaun , Shivnauth Vanessa , Castroverde Christian Danve M. 
Published: July 2023

AbstractMolecular genetic analyses in the model species Arabidopsis thaliana have demonstrated the major roles of different CALMODULIN‐BINDING PROTEIN 60 (CBP60) proteins in growth, stress signaling, and immune responses. Prominently, CBP60g and SARD1 are paralogous CBP60 transcription factors that regulate numerous components of the immune system, such as cell surface and intracellular immune receptors, MAP kinases, WRKY transcription factors, and biosynthetic enzymes for immunity‐activating metabolites salicylic acid (SA) and N‐hydroxypipecolic acid (NHP). However, their function, regulation, and diversification in most species remain unclear. Here, we have created CBP60‐DB (https://cbp60db.wlu.ca/), a structural and bioinformatic database that comprehensively characterized 1052 CBP60 gene homologs (encoding 2376 unique transcripts and 1996 unique proteins) across 62 phylogenetically diverse genomes in the plant kingdom. We have employed deep learning‐predicted structural analyses using AlphaFold2 and then generated dedicated web pages for all plant CBP60 proteins. Importantly, we have generated a novel clustering visualization algorithm to interrogate kingdom‐wide structural similarities for more efficient inference of conserved functions across various plant taxa. Because well‐characterized CBP60 proteins in Arabidopsis are known to be transcription factors with putative calmodulin‐binding domains, we have integrated external bioinformatic resources to analyze protein domains and motifs. Collectively, we present a plant kingdom‐wide identification of this important protein family in a user‐friendly AlphaFold‐anchored database, representing a novel and significant resource for the broader plant biology community.
Warm plasma catalytic coreforming of dilute bioethanol and methane for hydrogen production
Authors: Lian Hao‐Yu , Sun Zheng‐Wei , Ru Yun , Liu Jing‐Lin , Li Xiao‐Song , Zhu Ai‐Min 
Published: July 2023

AbstractToward hydrogen production from renewable sources, coreforming of dilute bioethanol (5 mol% ethanol) and methane using gliding arc discharge warm plasma is reported. For warm plasma alone, increases in methane to ethanol ratio and specific energy input lead to improving hydrogen yield, but low energy efficiency (<60%). The warm plasma coupled with Ni/CeO2/Al2O3 catalyst in a heat‐insulation reactor achieves an energy efficiency of 80%, but the large axial‐temperature drop of the catalyst bed causes low conversions. Therefore, additional heating is provided to maintain the catalyst bed temperature. Under optimal conditions, total carbon conversion of 97% and hydrogen yield of 78% are achieved with an energy cost of 1.16 kWh/Nm3 and energy efficiency of 85%.
Cooperative robust line‐of‐sight guidance law based on high‐gain observers for active defense
Authors: Luo Hongbing , Ji Haibo , Wang Xinghu 
Published: July 2023

SummaryIn this paper, a three‐body confrontation problem of a target‐defender team against an attacker is studied in three dimensions. To eliminate the system deviation that arises from the linearization of the model, a second‐order nonlinear model with normal acceleration as its input is established to describe the relative motion of three vehicles in three‐dimensional space. A high‐gain observer is designed to estimate the line‐of‐sight angular velocity in the case that system states cannot be measured. Based on disturbance rejection technique, a robust line‐of‐sight guidance law is developed in virtue of the estimated information for the target‐defender team so that the defender is able to intercept the attacker. Key features of the developed guidance law lie in that it does not need to know guidance information of the guidance law of the attacker in advance, and is robust to disturbance and uncertainty. Simulation examples are provided to demonstrate the effectiveness of the proposed guidance law.
Field demonstration of advanced autonomous navigation technique for a fully unmanned surface vehicle in complex coastal traffic areas
Authors: Han Jungwook , Park Hansol , Park Kyurin , Kim Sun‐Young , Lee Jae Yong , Pyo Chunseon 
Published: July 2023

AbstractThis study introduces an advanced autonomous navigation algorithm for unmanned surface vehicle (USV) operations in complex coastal traffic areas. To facilitate the undertaking of tests for innovative technologies, the Korean government has designated regulation‐free special zones, thereby enabling field tests for USV demonstrations without an onboard safety person on real manned‐ship navigation routes. To enable real‐world USV operation without onboard safety person, an existing autonomous navigation algorithm is extended to achieve sufficiently reliable and robust USV operation. Accordingly, berthing and unberthing algorithms are newly developed for unmanned operation, and enhanced situational awareness algorithms are applied to detect all types of obstacles, including small‐sized floating objects spread over a wide range, such as a fish farm. In particular, the Korean intelligent maritime transportation service, called e‐Navigation, is incorporated into the autonomous navigation algorithms to overcome the limitations of vehicle autonomy based on onboard sensors. To demonstrate the capability of fully unmanned operation in real marine traffic scenarios, long‐distance navigation (54 km on a single voyage) was conducted by running several missions, including navigation in complex fish farm areas, maritime surveys, collision avoidance, navigation on real traffic routes, and emergency response. The extended navigation algorithms and results of the field tests are presented and discussed in this paper.
Tailoring Writability and Performance of Star Block Copolypeptides Hydrogels through Side‐Chain Design
Authors: Garcia Ronnie V. , Murphy Elizabeth A. , Sinha Nairiti J. , Okayama Yoichi , Urueña Juan Manuel , Helgeson Matthew E. , Bates Christopher M. , Hawker Craig J. , Murphy Robert D. , Read de Alaniz Javier 
Published: July 2023

AbstractShear‐recoverable hydrogels based on block copolypeptides with rapid self‐recovery hold potential in extrudable and injectable 3D‐printing applications. In this work, a series of 3‐arm star‐shaped block copolypeptides composed of an inner hydrophilic poly(l‐glutamate) domain and an outer β‐sheet forming domain is synthesized with varying side chains and block lengths. By changing the β‐sheet forming domains, hydrogels with diverse microstructures and mechanical properties are prepared and structure–function relationships are determined using scattering and rheological techniques. Differences in the properties of these materials are amplified during direct‐ink writing with a strong correlation observed between printability and material chemistry. Significantly, it is observed that non‐canonical β‐sheet blocks based on phenyl glycine form more stable networks with superior mechanical properties and writability compared to widely used natural amino acid counterparts. The versatile design available through block copolypeptide materials provides a robust platform to access tunable material properties based solely on molecular design. These systems can be exploited in extrusion‐based applications such as 3D‐printing without the need for additives.
Laboratory-Based Evaluation of Exoskeletons in an Overhead Assembly Task
Authors: Ralfs Lennart , Peck Tobias , Weidner Robert 
Published: July 2023

AbstractIn recent years, the number of industrial exoskeletons has significantly increased. As a large share of assembly tasks still requires the execution of manual work, exoskeletons may help provide support to users and, thus, reduce physical strain on the human musculoskeletal system. However, exoskeletons still lack empirical evidence on their potential relieving effects on the human body and are, thus, not widely deployed in industrial applications yet. To investigate on exoskeleton’s impacts and promote their future adoption in the industry, industrial settings are increasingly modeled as different test scenarios in a laboratory environment. Within this frame, this paper presents a study (n = 4) investigating on effects of both an exemplary passive and active exoskeleton at an overhead screwing task. The qualitative and quantitative analysis by means of a questionnaire study as well as electromyographic investigations reveals significant support potentials of exoskeletons on users in assembly tasks.
Evaluation of the Ergonomic Potential of Adaptive Assembly Jigs for Large-Scale Products Using Human Modelling
Authors: Hogreve Sebastian , Wallmeier Hannah , Tracht Kirsten 
Published: July 2023

AbstractThe implementation of plug and fly principles for the assembly of high-lift systems requires the design of new work processes and jigs. Conventional jigs are inflexibly and lag of capabilities to adapt for product and process designs. Adaptive jigs provide higher flexibility and allow workers to position the product in accordance with their personal needs. This paper presents a novel wheel-shaped adaptive jig and investigates its influence on the ergonomics of assembling a high-lift system. A CAD program is used to model the high-lift system, the adaptive jig and workers. Based on these models, virtual scenes are generated that can be assessed with the key indicator method. The results show that the adaptive jig design improves ergonomics by eliminating the riskiest tasks during the assembly process. The adaptive jig concept has a high potential for improving production processes because it can respond flexibly to changes in the assembly process as well as to changes in product design.
Visual Programming of Robot Tasks with Product and Process Variety
Authors: Riedelbauch Dominik , Sucker Sascha 
Published: July 2023

AbstractIn flexible manufacturing settings, automation is shaped by ever changing conditions (e.g. varying part feeding locations, highly customizable products). Quick adaptation of robot systems is mostly achieved by visual end-user robot (re-)programming. In this paper, we discuss the explicit integration of anticipated product and process variety into visually programmed tasks. We contribute a task model which captures a user-defined range of task variants. To this end, parts are specified in terms of approximate locations and generalized parts families. Workspace exploration and combinatorial assignment planning enable online adaptation to unknown environments. Our experiments show that this adaptation capability can increase the economical efficiency of cobot use.
DOE Laser-assisted Turntable Calibration and Workpiece Registration
Authors: Schmidt Edgar , Ruppert Pascal , Henrich Dominik 
Published: July 2023

AbstractThe ability to review robot programs before they are executed can be used to correct erroneous programming. In complex processes, such a review can only be achieved by integration of additional peripheral devices and workpieces used into the programming framework. In this work, we present a semi-automatic method for the calibration of a turntable and a workpiece registration based on the turntable calibration utilizing only a DOE laser. The turntable pose is calculated by approaching markers on the turntable on a so called acquisition plane. Based on the calibration, workpieces are registered with intersection points between the laser beams with the turntable rotary plate. We evaluated our approach in terms of accuracy and the amount of time for execution. The resulting poses of the turntable and workpieces are used to load models into the 3D simulation of the programming framework and thus can be used to review the robot program.
Use of Autonomous UAVs for Material Supply in Terminal Strip Assembly
Authors: Boshoff Marius , Miro Michael , Sudhoff Martin , Kuhlenkötter Bernd 
Published: July 2023

AbstractThe multi-variant small part assembly of terminal strips requires innovative approaches for automated picking and meeting increased product variability demands with increasing process flexibility. Unmanned Aerial Vehicles (UAVs) are likely to be used in material supply for small parts and, therefore, replace manual picking of parts that are rarely needed in assembly. An autonomous material supply in the 3rd dimension could break up fixed assembly processes, reduce picking time and raise the production flexibility. In this article, the share of manual picking time in a real terminal strip assembly line is determined, and UAVs as a potential transport solution for terminals and jumpers are presented.
Exploratory Pilot Study for the Integration of Task-Specific Load Alternation into a Cyclic Assembly Process
Authors: Jansing Steffen , Rieger Christoph , Jabs Tim , Deuse Jochen , Wagenblast Florestan , Seibt Robert , Gabriel Julia , Spieler Judith , Rieger Monika , Steinhilber Benjamin 
Published: July 2023

AbstractTakt work represents a significant risk factor for the development of musculoskeletal complaints and diseases, especially in short-cycle processes. The increased risk results primarily from a permanent uniform load on the musculoskeletal system. Studies on motor variability suggest that an increase in load variation can have positive effects on reducing the risk.The research project “Integration of activity-specific load changes to reduce physical stress during takt work” aims to demonstrate the increase in load variation by introducing specific load changes during takt work as a possible means of preventing musculoskeletal disorders without causing negative effects on productivity. For this purpose, a pilot study was already carried out with ten subjects, which is presented in more detail in this paper.As foundation for the description of this study, the given paper first provides background on the applied theoretical concepts as well as the design of the overall research project. This is followed by the presentation of the experimental procedure and the results of the pilot study on cyclic assembly. Based on the stress profiles determined via surface electromyography the sequence of the analysed reference assembly process is reconfigured in order to integrate load changes. Future investigations within the research project are planned to compare both processes in terms of risk surrogate parameters for musculoskeletal disorders.
Verification and Integration of Safety Systems for Industrial Robot Cells Using Laser-Based Distance Measurement and Augmented Reality
Authors: Seim Patrick , Theren Benedict , Kutschinski Jürgen , Kuhlenkötter Bernd 
Published: July 2023

AbstractThe commissioning of robot cells requires an individual safety analysis followed by an appropriate dimensioning of safety components to ensure worker safety. With increasing complexity of robot work cells, developing proper safety concepts becomes more challenging. Therefore, updated validation concepts are needed that support safety engineers and reduce delay due to commissioning. This paper presents a solution to decrease the commissioning time for robot cells due to safety considerations and implementation of measurements. Data from a digital twin (DT) is used to generate test programs that are able to automatically measure relevant safety distances. The virtual robot cell is used to generate robot paths for the real cell. A distance sensor (laser based) measures the distance to relevant objects within the real cell. The programs run automatically, and the safety engineer only defines safety relevant points within the DT. Furter on, augmented reality (AR) is used to visualize safety zones specific to the induvial generated safety concept.