bluuebunny/crossref_metadata_2025 huggingface dataset:
The compact difference scheme for the fourth‐order nonlocal evolution equation with a weakly singular kernel
Authors: Zhou Ziyi , Zhang Haixiang , Yang Xuehua
Published: November 2022

In this paper, we main discuss an efficient numerical algorithm for the fourth‐order nonlocal evolution equation with a weakly singular kernel. The second‐order fractional convolution quadrature rule and L1 method are proposed to approximate the Riemann–Liouville (R‐L) fractional integral term and the temporal Caputo derivative, respectively. In order to obtain a fully discrete method, the compact difference scheme is used to discretize the second‐order and fourth‐order spatial derivative. Further, two new approaches are adopted for stability analysis, and then the optimal error estimates in the discrete
‐norm and
‐norm are obtained. At last, we give three test problems to illustrate the validity of the methods.
Superconvergence analysis of anisotropic finite element method for the time fractional substantial diffusion equation with smooth and nonsmooth solutions
Authors: Wang Zhongchi , Li Meng
Published: November 2022

In this work, anisotropic bilinear finite element and second‐order temporal approximation are adopted to establish a fully discrete scheme for the fractional substantial diffusion equation with variable coefficient. We prove the proposed discrete scheme is unconditionally stable in the senses of
‐norm and
‐norm. By introducing a new projection, the optimal convergence error in
‐norm and the superclose property in
‐norm are obtained under the condition of
, where
is the exact solution of the problem. Through interpolation post processing technique, we arrive at the global superconvergence of the interpolation. Furthermore, an improved algorithm is proposed to solve the problem with nonsmooth solution. Finally, numerical tests are given to illustrate the validity and efficiency of our theoretical analysis.
Deep neural network for retrieving material's permittivity from S‐parameters
Authors: Chrek Thorn , Nov Lihour , Chung Jae‐Young
Published: November 2022

This research proposed a deep neural network (DNN) model employing a multilayer feedforward artificial neural network to characterize the relative permittivity and loss tangent of a solid sample in a broad frequency range from 1 to 10 GHz. The method exploited a grounded coplanar waveguide as a measurement fixture, and a vast amount of data was obtained from full‐wave simulations. The latter was used to train the proposed DNN model. We performed parametric studies to examine optimal DNN hyperparameters and improve the efficiency of the material property retrieval process. The proposed model was validated by retrieving the relative permittivity and loss tangent of a known substrate. The results show good agreement with the known reference values with a slight error of 1.2%.
Comparative study an effect of polymethyl methacrylate coating on optical microbottle resonator for enhancing sensing performance for ethanol liquid sensor
Authors: Johari Md Ashadi Md , Apsari R. , Yasin M.
Published: November 2022

This paper observed the performance of the coated optical microbottle resonator (MBR) for the liquid ethanol concentration sensor. The MBR is prepared in three sizes by a technique known as “soften‐and‐compress” from silica fiber SMF‐28 with parameters named stem diameter, bottle length, and bottle diameter. The MBR is then coated with PMMA by the “drop‐casting” technique used as an ethanol sensor. The MBR‐PMMAs were characterized by microfiber diameter and managed to have a Q‐factor. The ethanol liquid concentration used is from 10% to 100% ppm. The sensitivity, linearity, repeatability, stability, and wavelength shift results were then used to determine the performance of MBR‐PMMAs as an ethanol sensor. The most significant size of MBR‐PMMA, known as “C,” is defined as an excellent ethanol liquid concentration sensor. Additionally, the resonator's size is determined and may influence its ability to perform well as a sensor.
C‐band high purity circularly polarized array with modified radial slots and electromagnetic band‐gap substrate configuration
Authors: Sedghi Tohid , Aribi Tohid , Lou Reza K. M.
Published: November 2022

Novel broadband circularly polarized (CP) electromagnetic band‐gap (EBG) antenna array was proposed in this paper. The antenna's radiating element is utilized by a microstrip‐fed circular patch, radial slot, and three rectangular notches. The proposed antenna elements are fed by feeding network comprised form four hybrid couplers and microstrip lines with appropriate lengths to support desired phase difference at output ports. Radiating patches are sequentially rotated to enhance CP property and form a 4 × 4 array. Finally, the novel scheme of electromagnetic structure (EBG) was inserted among radiating elements to decrease the mutual coupling. Using these structures results in the improvement of antenna bandwidth to cover the entire C‐band. In addition, CP purity is increased at the implicational band. Measured results indicate that the array has an impedance bandwidth of 4 GHz covering the C‐band totally and 3 dB axial‐ratio bandwidth of 2.6 GHz that is between 4.9 and 7.5 GHz (~42%). The antenna array has a peak gain of 8dBi at 6 GHz.
Printed collinear dipole array antenna with a horizontally omnidirectional pattern for dual‐band WLAN
Authors: Lee Kyoung‐Joo , Lee Keonmyung , Lee Tae‐Hak
Published: November 2022

A dual‐band printed dipole array antenna for a wireless local area network (WLAN) application is presented. A radiation element consists of four pairs of printed dipoles, and two radiation elements are collinearly arrayed. A broadside coupling microstrip line‐based two‐sectional impedance transformer is used to feed the radiation elements in parallel. The proposed dual‐band antenna is designed to cover the dual‐frequency bands (2.4–2.48 and 5.15–5.825 GHz) which are the lower‐ and upper‐frequency bands for WLAN operation. The experimental results support the proposed design theory and also exhibit the gain values of 3.89–4.88 and 5.79–7.18 dBi at the lower‐ and upper‐bands, respectively, maintaining the omnidirectional radiation pattern. The measured radiation efficiencies at each frequency points, 2.4, 5.2, and 5.5 GHz are 87.39%, 75.43%, 69.96%, and 73.07, respectively. In addition, for mass production, the effect from a low‐cost flexible coaxial cable, and polyethylene housing on the antenna performance is also investigated in this letter.
Damages and stress responses in sperm cells and other germplasms during dehydration and storage at nonfreezing temperatures for fertility preservation
Authors: Comizzoli Pierre , Amelkina Olga , Lee Pei‐Chih
Published: November 2022

Long‐term preservation of sperm, oocytes, and gonadal tissues at ambient temperatures has the potential to lower the costs and simplify biobanking in human reproductive medicine, as well as for the management of animal populations. Over the past decades, different dehydration protocols and long‐term storage solutions at nonfreezing temperatures have been explored, mainly for mammalian sperm cells. Oocytes and gonadal tissues are more challenging to dehydrate so little to no progress have been made. Currently, the detrimental effects of the drying process itself are better characterized than the impact of long‐term storage at nonfreezing temperatures. While structural and functional properties of germ cells can be preserved after dehydration, a long list of damages and stresses in nuclei, organelles, and cytoplasmic membranes have been reported and sometimes mitigated. Characterizing those damages and better understanding the response of germ cells and tissues to the stress of dehydration is fundamental. It will contribute to the development of optimal protocols while proving the safety of alternative storage options for fertility preservation. The objective of this review is to (1) document the types of damages and stress responses, as well as their mitigation in cells dried with different techniques, and (2) propose new research directions.
Investigation of polyamide 12 isothermal crystallization through the application of the phase‐field model
Authors: Teo How Wei Benjamin , Tran Van Thai , Chen Kaijuan , Le Kim Quy , Du Hejun , Zeng Jun , Zhou Kun
Published: November 2022

Crystallization of polyamide 12 (PA12) is an essential process requiring thorough investigation for evaluating the mechanical properties after the polymer parts are manufactured. The change in crystallization temperature results in different crystallization behaviors for PA12. Hence, the crystal morphology of PA12 achieved provides important information about crystallization behavior, especially for those produced through additive manufacturing due to its heterogenous cooling rate in a single print bed. Considering the need of investigating PA12 crystallization using phase‐field modeling, this paper aims to simulate the spherulite morphology of PA12 undergoing isothermal crystallization. This model is compared with the spherulite morphologies obtained from the optical microscopy test. The model shows that PA12 spherulites have thicker dendrites when the isothermal temperature is higher. The present phase‐field model can determine the spherulite morphologies of bulk printed PA12 based on the crystallization condition and be used to evaluate the properties of the printed part.
More extreme duplication in FDA Adverse Event Reporting System detected by literature reference normalization and fuzzy string matching
Authors: Hung Eric , Hauben Manfred , Essex Henry , Zou Chen , Bright Steve
Published: November 2022

Purpose

Literature reports of adverse drug events can be replicated across multiple companies, resulting in extreme duplication (defined as a majority of reports being duplicates) in the FDA Adverse Event Reporting System (FAERS) database because they can escape legacy duplicate detection algorithms routinely deployed on that data source. Literature reference field, added to in 2014, could potentially be utilized to identify replicated reports. FAERS does not enforce adherence to the Vancouver referencing convention, thus the same article may be referenced differently leading to duplication. The objective of this analysis is to determine if variations of the same literature references observed in FAERS can be resolved with text normalization and fuzzy string matching.

Methods

We normalized the literature references recorded in the FAERS database through the first quarter of 2021 with a rule‐based algorithm so that they better conform to the Vancouver convention. Levenshtein distance was then utilized to merge sufficiently similar normalized literature references together.

Results

Normalization of literature references increases the percentage that can be parsed into author, title, and journal from 61.74% to 93.93%. We observe that about 98% of pairs within groups do have a Levenshtein similarity of the title above the threshold. The extreme duplication ranged from 66% to 87% with a median of 72% of reports being duplicates and often involved addictovigilance scenarios.

Conclusions

We have shown that these normalized references can be merged via fuzzy string matching to improve enumeration of all the individual case safety reports that refer to the same article. Inclusion of the PubMed ID and adherence to the Vancouver convention could facilitate identification of duplicates in the FAERS dataset. Awareness of this phenomenon may improve disproportionality analysis, especially in areas such as addictovigilance.
Highly sensitive flexible strain sensor based on carbon nanotube/styrene butadiene styrene@ thermoplastic polyurethane fiber with a double percolated structure
Authors: Liu Libing , Xiang Dong , Zhang Xiangxia , Harkin‐Jones Eileen , Wang Junjie , Zhao Chunxia , Li Hui , Li Zhenyu , Wang Li , Wang Ping , Li Yuntao , Wu Yuanpeng
Published: November 2022

The combination of a high sensitivity and a wide strain detection range in conductive polymer composites‐based flexible strain sensors is still challenging to achieve. Herein, a double‐percolation structural fiber strain sensor based on carbon nanotubes (CNT)/styrene butadiene styrene (SBS)@thermoplastic polyurethane (TPU) composite was fabricated by a simple melt mixing and fused filament fabrication strategy, in which the CNT/SBS and TPU were the conductive and insulating phases, respectively. Compared with the sensor without the double percolated structure, the CNT/SBS@TPU sensor achieved a lower percolation threshold (from 2.0 to 0.5 wt%, a reduction of 75%), and better electrical and sensing performance. It is shown that the strain detection range of the CNT/SBS@TPU sensor increases with increasing CNT loading. An opposite trend was observed for the sensitivity. The 1%‐CNT/SBS@TPU sensor exhibited a high conductivity (1.08 × 10−3 S/m), high sensitivity (gauge factor of 2.65 × 106 at 92% strain), wide strain detection range (0.2%–92% strain), high degree of linearity (R2 = 0.954 at 0–10% strain), broad monitoring frequencies (0.05–0.5 Hz), and excellent stability (2000 cycles). Moreover, the CNT/SBS@TPU sensor was shown to successfully monitor a range of human physiological activities and to be capable of tactile perception and weight distribution sensing.
Chemical shifts of artificial monomers used to construct heterogeneous‐backbone protein mimetics in random coil and folded states
Authors: Rao Shilpa R. , Harmon Thomas W. , Heath Shelby L. , Wolfe Jacob A. , Santhouse Jacqueline R. , O'Brien Gregory L. , Distefano Alexis N. , Reinert Zachary E. , Horne W. Seth
Published: November 2022

The construction of protein‐sized synthetic chains that blend natural amino acids with artificial monomers to create so‐called heterogeneous‐backbones is a powerful approach to generate complex folds and functions from bio‐inspired agents. A variety of techniques from structural biology commonly used to study natural proteins have been adapted to investigate folding in these entities. In NMR characterization of proteins, proton chemical shift is straightforward to acquire and an information‐rich metric that bears directly on a variety of properties related to folding. Leveraging chemical shift to gain insight into folding requires a set of reference chemical shift values corresponding to each building block type (i.e., the 20 canonical amino acids in the case of natural proteins) in a random coil state and knowledge of systematic changes in chemical shift associated with particular folded conformations. Although well documented for natural proteins, these issues remain unexplored in the context of protein mimetics. Here, we report random coil chemical shift values for a library of artificial amino acid monomers frequently used to construct heterogeneous‐backbone protein analogues as well as a spectroscopic signature associated with one monomer class, β3‐residues bearing proteinogenic side chains, adopting a helical folded conformation. Collectively, these results will facilitate the continued utilization of NMR for the study of structure and dynamics in protein‐like artificial backbones.
Synthesis and testing of latex properties of copolymers of ethyl or butyl acrylate with methyl or butyl methacrylate and methacrylic acid
Authors: Makarewicz Edwin , Tworek Magdalena , Zalewska Anna , Tomaszewska Jolanta
Published: November 2022

The results of a study on latexes obtained by emulsion copolymerization of acrylic, methacrylic and vinyl monomers without surfactants are presented. The monomers included ethyl acrylate and butyl acrylate, methyl and butyl methacrylate and methacrylic acid. The yield of the copolymerization reaction, the polymer concentration in the latex, the pH, surface tension, intrinsic viscosity number, Huggins constant, the molecular weight of the polymer and the particle size in the latex were determined. The stability of the latexes was tested by determining the values of non‐overt and overt coagulation thresholds. The values of the limiting equivalent conductivity and the anode zeta potential were determined. The relative hardness of latex membranes and their mass change after hot water extraction were investigated. The relationships between the properties of individual latexes were established. The main aim of the research was to determine the influence of copolymer composition on the electrokinetic properties of polymer particles in latex. They determine the possibility of developing a new type of paint for electrophoretic painting with the use of latexes. © 2022 Society of Industrial Chemistry.
Autonomous measurement system for photovoltaic and radiometer soiling losses
Authors: Campos Laura , Wilbert Stefan , Carballo José , Meyer zu Köcker Juliane , Wolfertstetter Fabian , La Casa José , Borg Erik , Schmidt Karsten , Zarzalejo Luis F. , Fernández‐García Aránzazu , Santos Fernanda Norde , García Ginés
Published: November 2022

Soiling can greatly reduce both the efficiency of photovoltaic (PV) installations and the signals of radiometers. The knowledge of the current soiling losses of a PV installation can be used to optimize the cleaning schedule and to avoid false alarms related to other issues that might cause underperformance. Underperformance can be detected by comparing measured to modeled PV production derived using pyranometer or reference cell measurements. Soiled pyranometers or reference cells lead to too low modeled PV production so that PV soiling or other errors might not be detected. So far, soiling sensors either require frequent cleaning or they use indirect measurements to derive the soiling loss (e.g., analysis of backscattering signal or imaging of dust on a glass surface). Currently, the soiling loss of pyranometers or outdoor reference cells uses the comparison to another frequently cleaned device of the same model. To avoid time‐consuming maintenance of the sensors and to avoid additional sensors as much as possible, we developed a new method for measuring PV and radiometer soiling losses. The method makes use of a characterized lamp that is protected from soiling by a collimator and that illuminates the pyranometer or reference cell each night for some time. Comparing the signals of one night to the signal obtained at a night shortly after the last cleaning of the sensor, its soiling loss can be derived. To validate the measurements of soiling losses for the pyranometer and the reference cell, the soiling losses of the devices are also derived by comparing their signals to those of a clean sensor of the same type. These reference instruments are calibrated relative to the test devices so that deviations indicate the soiling loss of the test sensors. The first outdoor tests with 4 months of data show a good agreement with the reference measurements of the soiling losses. The accuracy of the method is estimated to be similar to that of the reference method, which involves the daily cleaning of the reference devices.
1D2DSimScore: A novel method for comparing contacts in biomacromolecules and their complexes
Authors: Moafinejad S. Naeim , Pandaranadar Jeyeram Iswarya P. N. , Jaryani Farhang , Shirvanizadeh Niloofar , Baulin Eugene F. , Bujnicki Janusz M.
Published: November 2022

The biologically relevant structures of proteins and nucleic acids and their complexes are dynamic. They include a combination of regions ranging from rigid structural segments to structural switches to regions that are almost always disordered, which interact with each other in various ways. Comparing conformational changes and variation in contacts between different conformational states is essential to understand the biological functions of proteins, nucleic acids, and their complexes. Here, we describe a new computational tool, 1D2DSimScore, for comparing contacts and contact interfaces in all kinds of macromolecules and macromolecular complexes, including proteins, nucleic acids, and other molecules. 1D2DSimScore can be used to compare structural features of macromolecular models between alternative structures obtained in a particular experiment or to score various predictions against a defined “ideal” reference structure. Comparisons at the level of contacts are particularly useful for flexible molecules, for which comparisons in 3D that require rigid‐body superpositions are difficult, and in biological systems where the formation of specific inter‐residue contacts is more relevant for the biological function than the maintenance of a specific global 3D structure. Similarity/dissimilarity scores calculated by 1D2DSimScore can be used to complement scores describing 3D structural similarity measures calculated by the existing tools.
Higher‐order interactions of Bcr‐Abl can broaden chronic myeloid leukemia (CML) drug repertoire
Authors: Liu Yonglan , Zhang Mingzhen , Jang Hyunbum , Nussinov Ruth
Published: November 2022

Bcr‐Abl, a nonreceptor tyrosine kinase, is associated with leukemias, especially chronic myeloid leukemia (CML). Deletion of Abl's N‐terminal region, to which myristoyl is linked, renders the Bcr‐Abl fusion oncoprotein constitutively active. The substitution of Abl's N‐terminal region by Bcr enables Bcr‐Abl oligomerization. Oligomerization is critical: it promotes clustering on the membrane, which is essential for potent MAPK signaling and cell proliferation. Here we decipher the Bcr‐Abl specific, step‐by‐step oligomerization process, identify a specific packing surface, determine exactly how the process is structured and identify its key elements. Bcr's coiled coil (CC) domain at the N‐terminal controls Bcr‐Abl oligomerization. Crystallography validated oligomerization via Bcr‐Abl dimerization between two Bcr CC domains, with tetramerization via tight packing between two binary assemblies. However, the structural principles guiding Bcr CC domain oligomerization are unknown, hindering mechanistic understanding and drugs exploiting it. Using molecular dynamics (MD) simulations, we determine that the binary complex of the Bcr CC domain serves as a basic unit in the quaternary complex providing a specific surface for dimer–dimer packing and higher‐order oligomerization. We discover that the small α1‐helix is the key. In the binary assembly, the helix forms interchain aromatic dimeric packing, and in the quaternary assembly, it contributes to the specific dimer–dimer packing. Our mechanism is supported by the experimental literature. It offers the key elements controlling this process which can expand the drug discovery strategy, including by Bcr CC‐derived peptides, and candidate residues for small covalent drugs, toward quenching oligomerization, supplementing competitive and allosteric tyrosine kinase inhibitors.
The Branes Behind Generalized Symmetry Operators
Authors: Heckman Jonathan J. , Hübner Max , Torres Ethan , Zhang Hao Y.
Published: November 2022

The modern approach tom‐form global symmetries in ad‐dimensional quantum field theory (QFT) entails specifying dimension topological generalized symmetry operators which non‐trivially link withm‐dimensional defect operators. In QFTs engineered via string constructions on a non‐compact geometryX, these defects descend from branes wrapped on non‐compact cycles which extend from a localized source / singularity to the boundary . The generalized symmetry operators which link with these defects arise from magnetic dual branes wrapped on cycles in . This provides a systematic way to read off various properties of such topological operators, including their worldvolume topological field theories, and the resulting fusion rules. We illustrate these general features in the context of 6D superconformal field theories, where we use the F‐theory realization of these theories to read off the worldvolume theory on the generalized symmetry operators. Defects of dimension 3 which are charged under a suitable 3‐form symmetry detect a non‐invertible fusion rule for these operators. We also sketch how similar considerations hold for related systems.
Managing safety critical equipment and design performance standards in major capital projects ‐ BP mad dog 2 project
Authors: Ong Chee Seang
Published: November 2022

For an offshore facility, identifying safety critical equipment (SCE) and ensuring that they are designed, built, installed, and commissioned based on certain design performance criteria is key to ensuring a safe design. In some parts of the world, such as in the North Sea, regulatory requirements dictate a mandatory third‐party verification of the SCE and their corresponding design performance criteria. In other parts of the world, such as in the Gulf of Mexico, however, there is no such regulatory requirement; it is, therefore, up to the operator to provide assurance that the SCE is designed, built and installed per the design criteria. This paper describes a methodology for ensuring the integrity of SCE implementation and applies the learnings from the BP Mad Dog 2 Project (Argos platform). This methodology provides assurance of the integrity of the SCE during the engineering and construction phases of a project, along with some valuable lessons learned from managing the assurance of the SCE on the project via multiple contractors. This paper discusses the identification of the SCE and provides a brief summary of the development of the relevant design performance criteria for each category of SCE. The paper focuses on a two‐step process to track each design criterion via conducting engineering assurance and then providing field verification, where the design criteria are tested either at the manufacturing site, construction site or through commissioning activities. Some valuable lessons learned from the Mad Dog 2 Project are shared, along with some of the potential pitfalls in managing the assurance process of the SCE design criteria, especially in a complex project organization where multiple contractors are involved.
Precise Design of VO2Thin Films for Smart Windows by Employing Thickness‐Dependent Refractive Index
Authors: Mahdieh Mohammad Hossein , Sohrabi Mehrad
Published: November 2022

Vanadium dioxide (VO2) is an adjustable refractive index material and has capability of behaving as semiconductor or conductor depending on its temperature. Such a condition makes it as a material which can be employed in fabricating thermochromic smart windows. The transmission characteristics of these type of windows strongly depend on the thickness of the film. Therefore, some calculations are required to optimize the VO2thickness. Since the refractive index of VO2thin film is thickness dependent, therefore, in calculating the transmission of light spectrum from VO2thin films, a unique refractive index cannot be utilized. Herein, using three theoretical models (Lorentz–Drude oscillator, Lorentz oscillator, and Tauc–Lorentz) and employing experimental results from previous reports, a collection of thickness‐dependent refractive indexes of VO2films is provided. More precise transmission can be achieved using this set of refractive index data in the calculations which agree with those of experiments. These results also make capable to determine optimized film thickness for any desired transmission performance. This method is useful for design of VO2‐based thermochromic smart windows.
Metallic VO2−x Nanobeam Implanted With an Insulating VO2 Segment Toward Artificial Electrical Modulation
Authors: Zhang Rui , Huang Tiantian , Yang Wanli , Zhang Lepeng , Xu Peiran , Chen Zhimin , Chen Xin , Dai Ning
Published: November 2022

Insulator–metal transition (IMT) in correlated vanadium oxides is among critical issues and has drawn significant attention in the communities of condensed matter physics, functional Mott materials and devices. It is always essential to understand and manipulate IMT behaviors in vanadium oxides toward advanced electronics and photonics. Selected‐area chemical nanoengineering (SACNE) enables direct modulating of structural compositions and physical/chemical properties. Herein, the realization of an IMT in metallic VO2−x nanobeams through artificially implanting an insulating VO2 segment is described. Original temperature‐dependent IMT behaviors are suppressed when insulating VO2 was reduced into metallic VO2−x. By exploiting an implanting nanoengineering, oxidation states and compositions to fabricate an insulating segment in the metallic VO2−x nanobeam are selectively controlled. Then, an abrupt temperature‐dependent resistance changing is demonstrated in the VO2−x nanobeam with implanted VO2 segment. It is expected that the modulations on segmental compositions and IMT behaviors in the VO2−x nanobeam would help for the understanding of correlated oxides and the construction of IMT‐based sensors and transistors.
Few electron systems confined in Gaussian potential wells and connection to Hooke atoms
Authors: Telleria‐Allika Xabier , Mercero Jose M. , Ugalde Jesus M. , Lopez Xabier , Matxain Jon M.
Published: November 2022

In this work, we have computed and implemented one‐body integrals concerning Gaussian confinement potentials over Gaussian basis functions. Then, we have set an equivalence between Gaussian and Hooke atoms and we have observed that, according to singlet and triplet state energies, both systems are equivalent for large confinement depth for a series of even number of electrons n = 2, 4, 6, 8 and 10. Unlike with harmonic potentials, Gaussian confinement potentials are dissociative for small enough depth parameter; this feature is crucial in order to model phenomena such as ionization. In this case, in addition to corresponding Taylor‐series expansions, the first diagonal and sub‐diagonal Padé approximant were also obtained, useful to compute the upper and lower limits for the dissociation depth. Hence, this method introduces new advantages compared to others.
Adaptive predefined‐time observer design for generalized strict‐feedback second‐order systems under perturbations
Authors: Lv Jixing , Ju Xiaozhe , Jing Liang , Wang Changhong
Published: November 2022

This article studies the predefined‐time observation problem of generalized strict‐feedback second‐order systems commonly encountered in practice. A nonaffine control input, a matched perturbation, and nonlinear functions satisfying the Hölder growth condition are considered. A class of adaptive predefined‐time observers (PTOs) is designed to reconstruct unknown states and lumped perturbations based on a barrier function and specific time‐varying functions. Distinct from existing observers for strict‐feedback systems, the PTO accomplishes a complete reconstruction in a predefined time with trivial peaking observation errors. Furthermore, the upper bound of the settling time of the PTO is tightly and explicitly predefined by only one design parameter, and is irrelevant to the initial conditions. Hence, tuning procedures for the physically realizable temporal demands become less conservative and more straightforward. Moreover, the adaptive coefficients of the PTO are self‐adjusted along with the magnitude of perturbation, efficiently improving the transient performance under wide‐range perturbations. Finally, numerical simulations on a robot manipulator system demonstrate the effectiveness of the PTO.
Robust stability and robust H2 performance of discrete‐time Markovian jump linear systems with uncertain transition probabilities
Authors: Zhang Chi , Lu Jun‐Guo
Published: November 2022

In this article, the robust stochastic stability problem and robust performance problem of discrete‐time Markovian jump linear systems with uncertain transition probabilities are investigated. Based on the Kronecker product and analysis, perturbation bounds are obtained for the robust stochastic stability of the investigated system by transforming the problem into checking whether a class of uncertain matrices is nonsingular. Furthermore, a sufficient and necessary condition for robust stochastic stability is derived. Similarly, by converting the problem to the judgment of the nonsingularity of uncertain matrices, the exact upper and lower bounds for robust performance are obtained. Then, a sufficient and necessary condition for guaranteeing robust performance is obtained. All the results are given in terms of the structured singular value. Finally, numerical examples are presented to show the effectiveness of the proposed results.
Longitudinal deep truck: Deep longitudinal model with application to sim2real deep reinforcement learning for heavy‐duty truck control in the field
Authors: Albeaik Saleh , Wu Trevor , Vurimi Ganeshnikhil , Chou Fang‐Chieh , Lu Xiao‐Yun , Bayen Alexandre M.
Published: November 2022

To develop cooperative adaptive cruise control (CACC), the choice of control approach often influences and can limit the choice of model structure, and vice versa. For heavy‐duty trucks, practical application of CACC in the field is heavily influenced by the accuracy of the used model. Deep learning and deep reinforcement learning (deep‐RL) have recently been used to demonstrate improved modeling and control performance for vehicles such as cars and quadrotors compared to state‐of‐the‐art. The literature on the application of deep learning and deep‐RL for heavy‐duty trucks in the field, which are significantly more complex than cars, is still sparse, however. In this article, we develop a two‐layer gray‐box deep learning model to capture longitudinal dynamics of heavy‐duty trucks while abstracting their complexity and present an approach to properly break the nested feedback loops in the model for training. We compare this model with three other alternative models and show that it achieves better general performance compared to a standard artificial neural network and results in and slower steady‐state acceleration and speed error growth rates, respectively. We then present an architecture to utilize these deep learning models within the deep‐RL framework and use it to develop baseline CACC controllers that can be zero‐shot transferred to the field. To carry out the work, we present a setup of differently configured trucks along with their interface architecture and stochastic driving cycle generators for data collection. Numerical validation of the approach demonstrated stationary and bounded modeling error, and demonstrated transfer of CACC controllers with consistent overshoot bounds and a stable approximately‐zero steady‐state error. Validation from field experiments demonstrated similarly consistent results. Compared to a state‐of‐the‐art benchmark, the deep‐RL controller achieved lower speed and time‐gap error variance but higher time‐gap error offset.
Frontiers in soil ecology—Insights from the World Biodiversity Forum 2022
Authors: Eisenhauer Nico , Bender S. Franz , Calderón‐Sanou Irene , de Vries Franciska T. , Lembrechts Jonas J. , Thuiller Wilfried , Wall Diana H. , Zeiss Romy , Bahram Mohammad , Beugnon Rémy , Burton Victoria J. , Crowther Thomas W. , Delgado‐Baquerizo Manuel , Geisen Stefan , Kardol Paul , Krashevska Valentyna , Martínez‐Muñoz Carlos A. , Patoine Guillaume , Seeber Julia , Soudzilovskaia Nadejda A. , Steinwandter Michael , Sünnemann Marie , Sun Xin , van der Heijden Marcel G. A. , Guerra Carlos A. , Potapov Anton
Published: November 2022

Global change is affecting soil biodiversity and functioning across all terrestrial ecosystems. Still, much is unknown about how soil biodiversity and function will change in the future in response to simultaneous alterations in climate and land use, as well as other environmental drivers. It is crucial to understand the direct, indirect and interactive effects of global change drivers on soil communities and ecosystems across environmental contexts, not only today but also in the near future. This is particularly relevant for international efforts to tackle climate change like the Paris Agreement, and considering the failure to achieve the 2020 biodiversity targets, especially the target of halting soil degradation. Here, we outline the main frontiers related to soil ecology that were presented and discussed at the thematic sessions of the World Biodiversity Forum 2022 in Davos, Switzerland. We highlight multiple frontiers of knowledge associated with data integration, causal inference, soil biodiversity and function scenarios, critical soil biodiversity facets, underrepresented drivers, global collaboration, knowledge application and transdisciplinarity, as well as policy and public communication. These identified research priorities are not only of immediate interest to the scientific community but may also be considered in research priority programmes and calls for funding.
The impact of penalties for environmental violations on corporate environmental responsibility
Authors: Li Ruiqian , Ramanathan Ramakrishnan , Xu Guanghua
Published: November 2022

Identifying firms' responses to the imposition of penalties for environmental violations in the context of corporate environmental responsibility (CER) is important to understand the impact of environmental penalties (EPs) and improve their design. Using a research sample consisting of Chinese listed firms in heavy polluting sectors from 2014 to 2020, we investigate whether and how penalties for environmental violations can affect subsequent CER engagement. The empirical results show that imposing one or more EPs on a firm has positive effects on the firm's subsequent CER practises. Our results remain robust after a series of tests. We also find that the role of EPs in promoting CER is more pronounced in firms that receive more media coverage, have weak political connections, and operate in less competitive industries. Further analysis shows that the dynamic effect of EPs on CER engagement persists at least 2 years after the imposition of the penalty and that EPs can stimulate CER practises through both symbolic and substantive actions.
The effect of powder reuse on the surface chemical composition of the Scalmalloy powder in Powder Bed Fusion – Laser Beam process
Authors: Martucci Alessandra , Tam Pui Lam , Aversa Alberta , Lombardi Mariangela , Nyborg Lars
Published: November 2022

The powder quality is one of the main factors to be considered in laser powder bed fusion (PBF‐LB/M) production closely connected with the performance of the final component. Only powders with spherical particles, a low percentage of satellites, a narrow particle size distribution, controlled internal defects and a strongly limited surface oxide layer are acceptable for PBF‐LB/M production. Gas atomisation is the main production method that permits to achieve the restrictive standards of the PBF‐LB/M powder; however, it is energy‐intensive and characterised by limited productivity. These considerations justify the key role of the reuse of the unmelted metal powder in obtaining a more sustainable PBF‐LB/M process. Nevertheless, the reuse of the powder leads to significant changes in the particle morphology, particle size distribution and surface chemical composition, which can compromise the bulk properties. Powder surface oxide is one of the most impactful problems for the PBF‐LB/M production, and Al‐based alloys are particularly prone to this phenomenon. With the aim to study the effect of the powder reuse, a surface chemical analysis on gas atomised Scalmalloy powder was performed through the X‐ray photoelectron spectroscopy investigation before and after seven jobs with 32 h as overall build time. Results obtained for virgin and recycled Scalmalloy powders revealed remarkable differences in depth and composition of the surface oxide layer. The 57% increase in the oxide layer thickness and the formation of carbides during PBF‐LB/M production can have harmful effects on bulk properties.
Training industrial end‐user programmers with interactive tutorials
Authors: Ritschel Nico , Sawant Anand Ashok , Weintrop David , Holmes Reid , Bacchelli Alberto , Garcia Ronald , K R Chandrika , Mandal Avijit , Francis Patrick , Shepherd David C.
Published: November 2022

Newly released robot programming tools have made it feasible for end‐users to program industrial robots by combining block‐based languages and lead‐through programming. To use these systems effectively, end‐users, who usually have limited or no programming experience, require training. To train users, tutoring systems are often used for block‐based programming—some even for lead‐through programming—but no tutorial system combines these two types of programming. We present CoBlox Interactive Tutorials (CITs), a novel tutoring approach that teaches how to use both the hardware and
software components that comprise a typical end‐user robot programming environment. As users switch between the two programming styles, CITs provide them with extensive scaffolding, give users immediate feedback on missteps, and provide guidance on next steps. To evaluate CITs, we conducted a study with 79 industrial end‐users using a programming environment released by ABB Robotics that compares our approach to training with training videos, the most commonly used training in industry. This study, one of the largest to date on training professional end‐users, found that CIT‐trained users authored more correct programs in less time than video‐trained users. This shows that a tight integration of hardware and software concepts is crucial to training end‐users to program industrial robots.
Effect of Cr on Isothermal Structure Transformation of Iron Oxide Scale
Authors: Cao Guangming , Wang Chenyang , Jiang Yuchen , Li Silin , Gao Xinyu , Liu Zhenyu
Published: November 2022

Herein, the effect of different contents of Cr on the isothermal structure transformation of FeO is systematically studied by a thermogravimetric analyzer, and it is found that the temperature range of eutectoid transformation of FeO in Fe–Cr alloy is 300–500 °C. Combined with the experimental data, the kinetic model of isothermal phase transformation of FeO is established based on Johnson–Mehl–Avrami–Kolmogorov equation, and the time–temperature–transformation curve of isothermal transformation of FeO is predicted, which follows the law of C curve, and the C curve shifts backward with the increase of Cr content. Therm‐calc thermodynamic software calculates the Fe–O phase diagrams of different Cr contents. Combined with the experimental results, the effect mechanism of Cr content on FeO eutectoid transformation is clarified. With the increase of Cr content, the stability of FeO decreases, and under the same isothermal temperature and time, high Cr content has greater undercooling, a higher driving force of phase transition, and the starting time of eutectoid transformation is earlier than that of lower Cr content.
Redistribution of internal forces from the span to the support
Authors: Berger Johannes , Haller Daniel
Published: November 2022

This paper presents the results of evaluations on the redistribution of internal forces from the span to the support area using nonlinear finite element calculations. The motivation is the internalization of bridges, particularly the reconstruction of single‐span beams arranged in a row to a continuous beam system. When integralizing a bridge, it can be assumed that the existing bridge is designed according to standards, which are no longer valid. If the integralized bridge is loaded and designed according to the new standard, the problem may be that the existing structure has insufficient reinforcement. For single‐span bridges, the flexural reinforcement in the span may be considered critical. The degree of reinforcement in the support area can then be adjusted individually, which offers the possibility of transferring internal forces from the span to the support area if they cannot be fully absorbed by the existing reinforcement.
Validating matches of electronically reported fishing trips to investigate matching error
Authors: Williams Benjamin , Zalsha Shalima , Stokes S. Lynne , McShane Ryan P. A. , Foster John
Published: November 2022

Objective

Recently, researchers have developed methods for combining probability samples and non-probability samples. In recreational fisheries management, data from probability samples are typically counts of catch from a random sample of trips intercepted by a sampler, while non-probability samples consist of catch data that are collected in self-reports made to a fishery management agency. These reports are typically transmitted electronically and are known as an electronic logbook (ELB). Even when such reporting is mandated, compliance is not universal. Since the inclusion probability for any particular angler is unknown, the ELB sample is a non-probability sample. We used data from a 2017 Gulf of Mexico (GoM) pilot study in which charter captains volunteered to electronically report their catch. At the dock, they could also be intercepted by a sampler, at which time their catch was observed. Estimates of total catch can be generated if trips from the two data sets can be accurately matched. Several states in the GoM implement similar ELB reporting augmented with a probability sample. However, there is an apparent discrepancy between National Oceanic and Atmospheric Administration (NOAA) estimates of the total and the ELB estimates for the same geographies. We seek to investigate the extent to which matching errors contribute to the discrepancies.

Methods

We employed probabilistic record linkage to match reports with intercepts and developed a validation tool to examine the matches. Using our validation tool, we examined several methods of estimating the total catch of Red Snapper Lutjanus campechanus in the GoM to investigate the potential cause of the discrepancy.

Result

We found the existing differences between the NOAA estimates and estimates resulting from combining ELB reports in this application were likely not due to matching error but instead were apparently derived from other sources of non-sampling error.

Conclusion

This has implications for new and existing ELB implementations, which are gaining popularity. The tool and results we provide can allow other implementations to better match reports with intercepts and offers a way to examine the extent to which matching errors affect the bias of estimates. Our work also shows that agencies should focus on non-sampling errors besides matching error to reduce bias. Our tool may also be extended to examine such non-sampling errors, such as the assumption that reporting and interception are independent.
Seismic design and assessment for midrise buildings equipped with damped‐outrigger system
Authors: Lin Pao‐Chun , Liu Kuang‐Yen , Yohanes Suryanto
Published: November 2022

The damped‐outrigger system has been proposed to improve the performance of conventional outrigger systems in controlling the structural seismic response by increasing the damping and stiffness. The purpose of this study is to demonstrate the effectiveness of using damped‐outrigger systems in midrise buildings and provide engineers with a comparison between conventional structural systems such as moment resisting frame (MRF) and buckling‐restrained braced frame (BRBF) in proposing the most suitable structural system. In this study, the buckling‐restrained brace and viscous damper are adopted as the energy dissipation devices in the damped‐outrigger system. A total of 48 midrise numerical models with various building heights and structural systems are analyzed using nonlinear response history analysis and incremental dynamic analyses. The analysis results show that the midrise buildings equipped with a damped‐outrigger system with either viscous damper or buckling‐restrained brace (BRB) can reach similar and even better seismic performance when compared with the BRBF; it also reduces the structural responses by around 30% for the maximum roof drift and acceleration responses when compared with MRF. The analysis results could provide a reference for structural engineers when selecting suitable lateral force resisting systems for midrise buildings.