bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization and Identification of Drought-Responsive ABA-Aldehyde Oxidase (AAO) Genes in Potato (Solanum tuberosum L.)
Authors: Yao Panfeng , Zhang Chunli , Zhang Dan , Qin Tianyuan , Xie Xiaofei , Liu Yuhui , Liu Zhen , Bai Jiangping , Bi Zhenzhen , Cui Junmei , Liang Jingwen , Sun Chao
Published: November 2023

Abscisic acid (ABA) is an important stress hormone that affects plants’ tolerance to stress. Changes in the content of abscisic can have an impact on plant responses to abiotic stress. The abscisic acid aldehyde oxidase (AAO) plays a crucial role in the final step in the synthesis of abscisic acid; therefore, understanding the function of the AAO gene family is of great significance for insight into plants’ response to abiotic stresses. In this study, Solanum tuberosum AAO (StAAO) members were exhaustively explored using genome databases, and nine StAAOs were identified. Chromosomal location analysis indicated that StAAO genes mapped to 4 of the 14 potato chromosomes. Further analyses of gene structure and motif composition showed that members of the specific StAAO subfamily showed relatively conserved characteristics. Phylogenetic relationship analysis indicated that StAAOs proteins were divided into three major clades. Promoter analysis showed that most StAAO promoters contained cis-elements related to abiotic stress response and plant hormones. The results of tissue-specific expression analysis indicated that StAAO4 was predominantly expressed in the roots. Analysis of transcriptome data revealed that StAAO2/4/6 genes responded significantly to drought treatments. Moreover, further qRT-PCR analysis results indicated that StAAO2/4/6 not only significantly responded to drought stress but also to various phytohormone (ABA, SA, and MeJA) and abiotic stresses (salt and low temperature), albeit with different expression patterns. In summary, our study provides comprehensive insights into the sequence characteristics, structural properties, evolutionary relationships, and expression patterns of the StAAO gene family. These findings lay the foundation for a deeper understanding of the StAAO gene family and offer a potential genetic resource for breeding drought-resistant potato varieties.
Fuzzy Modeling Development for Lettuce Plants Irrigated with Magnetically Treated Water
Authors: Ferrari Putti Fernando , Cremasco Camila Pires , Neto Alfredo Bonini , Barbosa Ana Carolina Kummer , Júnior Josué Ferreira da Silva , Reis André Rodrigues dos , Góes Bruno César , Arruda Bruna , Filho Luís Roberto Almeida Gabriel
Published: November 2023

Due to the worldwide water supply crisis, sustainable strategies are required for a better use of this resource. The use of magnetic water has been shown to have potential for improving irrigation efficacy. However, a lack of modelling methods that correspond to the experimental results and minimize error is observed. This study aimed to estimate the replacement rates of magnetic water provided by irrigation for lettuce production using a mathematical model based on fuzzy logic and to compare multiple polynomial regression analysis and the fuzzy model. A greenhouse study was conducted with lettuce using two types of water, magnetic water (MW) and conventional water (CW), and five irrigation levels (25, 50, 75, 100 and 125%) of crop evapotranspiration. Plant samples for biometric lettuce were taken at 14, 21, 28 and 35 days after transplanting. The data were analyzed via multiple polynomial regression and fuzzy mathematical modeling, followed by an inference of the models and a comparison between the methods. The highest biometric values for lettuce were observed when irrigated with MW during the different phenological stage evaluated. The fuzzy model provided a more exact adjustment when compared to the multiple polynomial regressions.
Molecular Basis of Crops and Fruit Plants in Response to Stress
Authors: Costa Jose Helio , Miranda Rafael de Souza
Published: November 2023

This editorial summarizes the main scientific contributions from 11 papers comprising the Special Issue (SI) “Molecular Basis of Crops and Fruit Plants in Response to Stress”. Here, we collected papers from different research groups encompassing molecular studies from monocots (ginger, rice, maize) and eudicots (common hazel, cowpea, pepper, soybean, tomato) species submitted to abiotic stresses as heat, cold, salt, drought, and heavy metals or biotic stresses induced by different viruses, such as BPEV, PepGMV, PMMoV, and TEV. These studies explored different aspects of molecular mechanisms involved in plant stress tolerance, establishing comparative analyses among genotypes/cultivars to identify potential molecular markers of stresses that are now available for future application in biotechnological studies. This SI presents a collection of advanced concepts and emerging strategies for readers and researchers aiming to accelerate plant breeding.
miR2118 Negatively Regulates Bacterial Blight Resistance through Targeting Several Disease Resistance Genes in Rice
Authors: Zhu Xiumei , Kuang Yongjie , Chen Yutong , Shi Jia , Cao Yaqian , Hu Jixiang , Yu Chao , Yang Fenghuan , Tian Fang , Chen Huamin
Published: November 2023

Plant miRNAs are a class of noncoding RNA with a length of 21–24 nt that play an important role in plant responses to biotic and abiotic stresses. Bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most serious bacterial diseases in rice. Our previous work showed that osa-miR2118b/n was induced by Xoo infection. However, the biological function of miR2118 has not yet been characterized in experiments. Herein, we constructed MIR2118b OE, as well as single and double mutants of MIR2118b/n using CRISPR/Cas9. Further results showed that osa-MIR2118b OE plants exhibited longer lesion lengths than the wild type after Xoo inoculation, while MIR2118 CRISPR plants exhibited shorter lesion lengths than the wild type after Xoo inoculation. Co-transformation experiments in rice protoplasts indicated that osa-miR2118 negatively regulated the transcripts of three nucleotide-binding sites and leucine-rich repeat (NLR) genes (LOC_Os08g42700.1, LOC_Os01g05600.1, and LOC_Os12g37290.1) which are predicted target genes of miR2118, but not the mutated NLR genes with a 3 bp insertion at the center of the binding sites. The transcriptional level of the three NLR genes was reversed relative to osa-miR2118 in the MIR2118b OE and MIR2118b CRISPR plants. The above results demonstrate that osa-miR2118b/n negatively regulates the resistance to bacterial blight through negatively regulating several NLR genes.
Research on the Calculation Method for the Wellbore Temperature of Hot Nitrogen Gas Circulation Wax Removal and Plug Removal in Offshore Oil Fields
Authors: Du Weigang , An Yongsheng , Guan Liyong , Xiong Chengchen , Huo Runshi , Tang Bing
Published: November 2023

The problem of wax deposition widely exists in offshore oil fields; waxing of the oil tubing will lead to a reduction in the cross-sectional area of the flow and, in serious cases, the flow path will be blocked, causing the well to stop production. In order to cope with this problem, a thermal dynamic wax removal method has emerged in recent years that utilizes hot nitrogen gas circulation between the oil tube and annulus to raise the temperature of the oil tube to achieve the purpose of wax removal and plug removal and is quick and easy to operate. Unlike conventional wellbore temperature calculation methods, the wellbore temperature field under hot nitrogen circulation conditions is influenced both by the reservoir temperature gradient and the hot nitrogen injection temperature, injection pressure, and injection rate. In this paper, a temperature calculation model for a wellbore considering both annulus injection temperature and tubing temperature and their interactions is modeled, which can consider the effects of different hot nitrogen injection temperatures, injection rates, and injection pressures. The model is used to calculate the temperature distribution for different injection parameters in order to ensure that the tubing temperature is higher than the wax precipitation temperature and that the annulus temperature is not higher than the maximum temperature resistance of the rubber in the packer. The study provides a design method for wax removal and plug removal with hot nitrogen gas circulation.
Effect of Non-Uniform Minerals Distribution on Hydraulic Fracture Evolution during Unconventional Geoenergy Exploration
Authors: Gao Ziqi , Li Ning , Tu Jiahui , Yang Liu
Published: November 2023

To study the effect of the non-uniform distribution of minerals on the development of microcracks within the rock during hydraulic fracturing, a novel numerical model considering multiple random mineral distributions was designed. The model investigated the impacts of mineral grain size, composition, and spatial arrangement on fracture initiation and propagation. The results indicate that the presence of the hard-phase mineral quartz can alter the propagation path of fractures, and increase the width of hydraulic fractures. In coarse-grained granite, the range of crack deflection is maximized, while in medium-grained granite, it is more prone to forming convoluted elongated cracks. A higher quartz content in granite further contributes to the formation of complex crack networks. Simultaneously, the evolution of granite fractures and variations in breakdown pressure in heterogeneous granite were investigated, considering the influence of core parameters such as fluid injection rate, fracturing fluid viscosity, and horizontal stress difference. The research reveals that a high injection rate promotes straight-line fracture expansion. Moreover, modest fluctuations in fracturing fluid viscosity have minimal effects on fracture morphology. When the fracture development avoids quartz, under the influence of high horizontal stress differential, it clearly turns toward the direction of the maximum principal stress. This study can offer insights into innovative and optimized deep reservoir fracturing techniques.
What Do Pupils Learn from Voting Advice Applications in Civic Education Classes? Effects of a Digital Intervention Using Voting Advice Applications on Students’ Political Dispositions
Authors: Waldvogel Thomas , Oberle Monika , Leunig Johanna
Published: November 2023

To what extent does the use of Voting Advice Applications in (digital) civic education classes at school impact students’ political knowledge, attitudes, motivations and behavioral dispositions toward elections? This article provides answers to this question by presenting a sample analysis of the responses of 1189 pupils who participated in a digital civic education intervention, with the German Voting Advice Application Wahl-O-Mat at its core, whose usage was embedded in an elaborated didactical concept in civic education classes. Using a quasi-experimental field design with pre- and post-tests, the study shows that the intervention substantially improves students’ knowledge of the investigated state election. Furthermore, we can trace a significant increase in young people’s political efficacy and specific interest in the election campaign. Finally, we observe a substantial increase in intended electoral participation, especially among those adolescents whose intention to participate in elections was low prior to the intervention, which contributes to a reduction in existing participation gaps. In particular, we identify changes in motivational and cognitive political dispositions, but only to a limited extent evaluative and sociodemographic background variables, as key factors driving the intervention-induced change in willingness to participate in the state election. Our paper concludes by discussing the limitations of the study and its implications for empirical research and practice in civic education.
Advancements in Vaccine Adjuvants: The Journey from Alum to Nano Formulations
Authors: Moni Sivakumar , Abdelwahab Siddig , Jabeen Aamena , Elmobark Mohamed , Aqaili Duaa , Gohal Gassem , Oraibi Bassem , Farasani Abdulla , Jerah Ahmed , Alnajai Mahdi , Mohammad Alowayni Abdul
Published: November 2023

Vaccination is a groundbreaking approach in preventing and controlling infectious diseases. However, the effectiveness of vaccines can be greatly enhanced by the inclusion of adjuvants, which are substances that potentiate and modulate the immune response. This review is based on extensive searches in reputable databases such as Web of Science, PubMed, EMBASE, Scopus, and Google Scholar. The goal of this review is to provide a thorough analysis of the advances in the field of adjuvant research, to trace the evolution, and to understand the effects of the various adjuvants. Historically, alum was the pioneer in the field of adjuvants because it was the first to be approved for use in humans. It served as the foundation for subsequent research and innovation in the field. As science progressed, research shifted to identifying and exploiting the potential of newer adjuvants. One important area of interest is nano formulations. These advanced adjuvants have special properties that can be tailored to enhance the immune response to vaccines. The transition from traditional alum-based adjuvants to nano formulations is indicative of the dynamism and potential of vaccine research. Innovations in adjuvant research, particularly the development of nano formulations, are a promising step toward improving vaccine efficacy and safety. These advances have the potential to redefine the boundaries of vaccination and potentially expand the range of diseases that can be addressed with this approach. There is an optimistic view of the future in which improved vaccine formulations will contribute significantly to improving global health outcomes.
A deterministic energy method for predicting the response of coupled finite structures
Authors: Yang Yi
Published: November 2023

The forced response of finite, thin rectangular plates coupled by a line joint can be predicted using well-established analytical methods. However, such methods become difficult to implement for thick panels coupled by complex joints. In these cases, the finite element (FE) method and
conventional statistical energy analysis (SEA) are viable alternatives. However, the FE method can be time-consuming at mid/high frequencies while SEA involves various approximations and assumptions. This paper develops a deterministic energy method for predicting the forced response of coupled
complex panels based on a hybrid finite element/wave finite element method (WFE), modelling the panels as coupled wave-bearing subsystems. Excitation of the structure by a time-harmonic point force is considered. The method involves meshing only a small segment of the panel and the joint using
finite elements, and is able to model complex structures such as laminated panels and joints with low computational cost. An illustrative example of the method is presented - coupled thin, rectangular plates coupled by an "L" shaped joint.
Scattering from a partially coated shell immersed in water using a subtractive modelling technique
Authors: Dumortier Florent
Published: November 2023

In this study, we focus on the prediction of the pressure field scattered from an immersed cylindrical shell partially coated by a soft rubber, impacted by an acoustic plane wave. As the coating covers only a partial portion along the circumference of the shell, the considered system
is not axisymmetric. As a result, a spectral (Fourier) resolution of the mathematical problem would induce the coupling of the di erent circumferential orders, which can lead to prohibitive computing times. To circumvent this issue, the reverse Condensed Transfer Function (rCTF) method has
recently been developed to decouple vibroacoustic subsystems initially coupled along lines or surfaces. From an analytical model of the fully coated shell impacted by the acoustic plane wave and a finite element (FE) model of the missing coating material, the rCTF approach predicts the vibroacoustic
behavior of the coated shell with a voided section instead of the removed part. This voided section can then be filled by a FE model of the water domain replacing the removed coating material, using the direct CTF approach. The principle of the rCTF approach, some numerical validations, and
results for the scattering from the partially coated shell are presented in this paper.
New porous absorber simulation techniques in the context of finite element modelling
Authors: Bronzova Mariia
Published: November 2023

Porous liners are widely used as vibration and acoustics isolation materials due to their high absorbing qualities in a wide frequency range. In a car body porous plates are laid on top of a metal structure to prevent vibroacoustic wave propagation inside the passenger cabin. Unfortunately,
currently used FEM (finite element method) simulation models for poroelasticity Biot's equations are still unable to efficiently describe such coupled structure-liner-fluid systems due to the lack of modelling precision. The current paper focuses on the importance of the phenomena taking place
on the structure-liner interface during dynamic excitations in the frequency range of 10-1000 Hz. Measurements of transfer functions for numerous foam samples with varying boundary conditions have been conducted in a vacuum chamber to estimate the effect of interface conditions. New simulation
approaches are presented to account for the observed phenomena. Moreover, the issues of measurement uncertainties regarding foam material parameters (or Biot parameters) and poor measurement reproducibility have been addressed and corresponding parameter optimization schemes have been implemented.
As a result, a significant improvement in the agreement between simulation and measurement results has been achieved. All simulations have been conducted in a custom FEM code based on the open-source Deal II library.
Computing dispersion relations with modal analysis methods
Authors: Marra Da Silva Ribeiro Luiz Henrique
Published: November 2023

Dispersion diagrams depicting dispersion relations are usually computed from a periodic structure single unit cell using either analytical methods, such as the plane wave expansion (PWE) method, or numerical methods, such as the wave finite element (WFE) method, by applying Bloch-Floquet
periodic boundary conditions. However, the latter is still not available in most commercial FE codes. In this work, we propose a method to compute the dispersion diagram using standard modal analysis tools available in FE commercial codes currently used for structural analysis. We show that
if a metastructure consisting of a few cells is "periodized" by "wrapping around" the degrees of freedom at its ends, its natural frequencies will be points on the dispersion curve pass bands. The wavenumbers corresponding to these natural frequencies can be obtained from
the corresponding vibration modes using Prony's method. These natural frequencies are real for Hermitian structures and complex for non-Hermitian structures. Besides providing a useful tool for wave dispersion analysis using standard FE codes, the proposed method provides interesting insights
into the dynamics of periodic structures. The proposed method is applied to simple passive and active periodic rod structures.
Multi-fidelity modeling using Gaussian processes for the frequency dependent Helmholtz equation
Authors: Gurbuz Caglar
Published: November 2023

In scientific and engineering problems, accurate model predictions are generally accompanied with high resource and time expenses. In most applications, the data generation process can only be performed for a limited number of forward evaluations leading to insufficient model results.
The concept of multi-fidelity modeling is to holistically evaluate data from different sources with varying complexity and costs. Ideally, the predictive quality of models with a high-fidelity can be combined with the efficiency of low-fidelity models. Usually, physical experiments and numerical
simulations at large-scale are attributed to high-fidelity models, while analytical solutions or small-scale numerical models and experiments are considered as low-fidelity models. This contribution aims to develop a multi-fidelity model for an interior sound propagation problem. More specifically,
a vehicle interior noise problem is investigated by using two boundary element models of different fidelity levels. The finer mesh corresponds to the high-fidelity model, whereas the coarser mesh is adopted as the low-fidelity model. As such, the multi-fidelity model is realized as a vector-valued
Gaussian process.
Impact sound insulation prediction and uncertainty quantification using a detailed source model in the modal Transfer Matrix Method
Authors: Vastiau Jasper
Published: November 2023

The main goal of this work is to provide an efficient and accurate prediction of the impact sound insulation of layered structures for the entire building acoustics frequency range (50-5000 Hz). To this end, the modal Transfer Matrix Method (mTMM) has been developed to predict the impact
sound radiation from layered floors resulting from tapping machine impacts, while accounting for simply supported boundary conditions. A detailed source model is presented which accounts for both the impact locations of the individual hammers and the discrete 2 Hz force spectrum. It is also
discussed how this detailed source model can be implemented into the mTMM. Monte Carlo simulations provide insight into the uncertainty of the radiated sound power and the impact sound insulation improvement for bare and layered floors, resulting from the impact force location. Numerical validation
is provided by comparison to finite element models of various floors. Narrow-band sound pressure level measurements on a layered floor have been performed to validate the detailed source model and its use in the mTMM. A comparison of measured and predicted results indicates the importance
of a detailed source approach, especially at low frequencies
Elastic wave reflection in beams with acoustic black hole termination under axial excitations
Authors: Sepehrirahnama Shahrokh
Published: November 2023

The wave speed in structures can be controlled by altering their stiffness through variations of the geometry and dimensions of the cross-section along its length. Theoretically, slowing down the elastic waves can lead to a zero-reflection effect, which is referred to as acoustic black
hole (ABH). ABH has been demonstrated in metallic structures with isotropic-like material properties; while the effects of material anisotropy such as wood mechanical properties on the ABH effect are yet to be explored. We demonstrate numerically and experimentally the ABH effect in wood beams
(Pinus radiata) of different lengths by applying an exponential reduction of the circular cross-section. The beams are knot-free and made of cuts of 40mm, 80mm, 100mm, 120mm and 160mm length along the grain, which could lead to a small Poisson ratio by about one order of magnitude. An increase
in moisture content of the ABH wood beams by about 8-10% of the dry weights(N=5 samples) and a higher volume fraction of fibrous grains have been shown to reduce the wave reflection, as the drier and lower volume fraction the fibre, the higher the reflection becomes. This work can lead to
design of novel elastic wave-guides for timber structures as used in buildings and wooden infrastructure or construction processes
An accelerated deflation preconditioner for acoustic BEM systems based on subspace recycling
Authors: Panagiotopoulos Dionysios
Published: November 2023

Following a classic Krylov subspace recycling [1] technique in the context of frequency sweep analyses performed with the acoustic BEM [2] might inflict unnecessary overhead costs. To speed up such a procedure, this work employs an accelerated recycling technique that is based on the
recently proposed model order reduction framework for BEM systems [3]. Specifically, employing an affine approximation of a BEM system in combination with a Galerkin projection on the deflation basis, the operation of constructing the corresponding deflation based preconditioner is significantly
accelerated. The efficiency of the deflation basis for the entire frequency range is guaranteed through an Automatic Krylov subspace Recycling (AKR) [4] algorithm, thus leading to a drastic decrease of the number of iterations required by an iterative solver. The proposed approach is tested
on an academic BEM example and achieves significant acceleration of the computed frequency sweep by ensuring fast convergence of the employed iterative solver, avoiding overhead projection costs.
Laboratory implementation of the noise correlation methodology for leak location in water distribution systems
Authors: Fausti Patrizio
Published: November 2023

Nowadays, reducing the loss of water resources is of primary concern in many countries worldwide. Different methodologies exist for the identification and localisation of leaks in water distribution networks, which can be applied simultaneously at a different scale, to improve success
rate. Acoustic correlation has been employed for many years to localise such leakages, based on the post-processing of vibroacoustic signals acquired by two sensors placed on both sides of the pipe where the leakage is supposed to be located. The practical application of this methodology still
presents some significant issues. The implementation of the noise correlation methodology was investigated through an experimental test rig by simulating leakages in different conditions of pressure and flow and investigating the effects of background noise. Hydrophonic measurements and recordings
were performed, identifying the frequency range affected by the leak noise, and the signal to assess the accuracy of the noise correlation method. A pre-filtering of the signals to reduce the effect of background noise masking was also investigated. The accuracy of acoustic correlation in
localising the leakage was assessed by computing the propagation velocity, which depends on the vibroacoustic fluid-structure interaction, through approximated analytical equations
A neural network-augmented two-microphone impedance tube method to estimate sound propagation characterisics
Authors: Eser Martin
Published: November 2023

Two-microphone impedance tubes are a popular method to measure the normal incidence sound absorption coefficient. However, a single measurement with this method does not offer enough information to identify the sound propagation characteristics, i.e. the characteristic impedance and
the wave number of absorbent samples. Instead, more elaborate measurement techniques that require more time, more equipment and enhanced user knowledge need to be applied. This contribution presents a technique combining neural networks and the two-microphone impedance tube method to estimate
the propagation characteristics of a highly porous sample from a single two-microphone impedance tube measurement. The measured surface impedance serves as input to a U-net architecture, which preserves the high frequency resolution of the data and returns an estimate of the surface impedance
mimicking an air cavity attached behind the sample. Then, the two cavity method is used to calculate the propagation characteristics from the measured and the networks predicted surface impedances. The presented approach gives precise estimates of the propagation characteristics of simulated
highly porous samples and for two different, physically measured melamine foam samples, while drastically reducing the required resources and expenses. In this way, it provides an efficient way to estimate the propagation characteristics of absorbent samples.
Acoustic evaluation of a vehicle cabin by using energy-based surface contributions
Authors: Garbuz Caglar
Published: November 2023

Contribution analyses play a crucial role in the design process of vehicle cabins. In current implementations, however, surface contributions are only evaluated for single field points. The identification of surface contributions with regard to an entire cavity is accompanied with a
cumbersome volume integral. This study aims to abridge this tedious volume integral by evaluating the surface contributions regarding a grid with regularly distributed field points. For this purpose, the boundary element method is used to solve the acoustic Helmholtz equation. In contrast
to current techniques, the sound energy is deployed as the objective function. As the sound energy is sensitive to the sound pressure and the particle velocity, surface contributions can be also identified in regions with low sound pressure values. In order to validate the proposed framework,
the vehicle interior noise problem is examined. Initial findings confirm the relevance of energy-based surface contributions, as entire volumes can be acoustically evaluated in an efficient way.
Determination of Johnson-Champoux-Allard model parameters with machine learning techniques
Authors: Casaburo Alessandro
Published: November 2023

Acoustic modelling of materials is a key aspect to perform reliable predictions of untested configurations and to implement optimal strategies, especially nowadays, due to the development of 3D printing techniques allowing to generate deterministic microstructures in porous materials.
However, this modelling is not straightforward due to the number of parameters characterizing porous materials. Each one of these parameters can be estimated experimentally with its own setup and procedure, not always easy to execute. On the other hand, the use of inverse methods for the estimation
of parameters relies on physical approximations and requires experimental procedures that are strongly sensitive to boundary conditions. Consequently, experimental determination of the parameters of porous materials may become financially expensive and very time consuming. The purpose of this
work is to investigate the performances of machine learning techniques in determining the parameters of Johnson-Champoux-Allard model, in order to understand whether missing values can be predicted just relying on a set of already performed experimental characterizations when not all the experimental
setups are available. In particular, Gaussian processes are used on a training set describing porous materials in terms of Johnson-Champoux-Allard parameters and the values of acoustic indices at fixed frequencies.
Locally resonant metamaterials with multimodal resonators for sound insulation improvement
Authors: Giannini Daniele
Published: November 2023

Locally resonant metamaterials are used to increase the sound insulation of a host structure, by introducing bandgaps for wave propagation. While most solutions employ periodic layouts with translational resonators, this work investigates the potential of rotational and multimodal resonators.
A comprehensive analytical model of sound insulation, based on dynamic effective mass density, is first presented. It is then demonstrated how multimodal locally resonant metamaterials can suppress the broad coincidence dip in the diffuse transmission loss of orthotropic host plates, and the
geometry of two realizable multimodal resonators is optimized to maximize broadband sound insulation.
Parametric study of the axial force and negative stiffness of an electromagnetic mechanism for vibration isolation applications
Authors: Shahraeeni Mehran
Published: November 2023

Nonlinear vibration isolators that take advantage of negative stiffness elements can provide high static stiffness to bear high static loads and quasi-zero dynamic stiffness to widen the isolation frequency band and hence are desirable for vibration isolation. Electromagnetic negative
stiffness elements can be used to design and fabricate quasi-zero-stiffness vibration isolators. Different combinations of permanent magnets and electromagnetic coils in attractive or repulsive configurations can lead to negative stiffness. The magnitude of the electromagnetic restoring force
and negative stiffness is dependent upon many geometric and electromagnetic parameters and is controllable by adjusting the current in the electromagnetic coils. The present work compares the negative stiffness properties of three different configurations and provides a general guideline for
selecting the appropriate configuration. The finite element method is used to simulate the magnetic fields and electromagnetic force acting on the permanent magnet. Numerical results are presented, and findings are validated by analytical solutions.
Degradation and damage analysis of composite pressure vessels via experimental modal analysis
Authors: John Sebastian
Published: November 2023

For mobile gas storage systems, the application of type IV pressure vessels is state of the art. Type IV tanks consist of an inner polymer liner fully wrapped with fibre-reinforced plastic (FRP). Because of the complex fabric of the FRP as well as a difficulty estimable interaction
behaviour between the single components under load, there are still no satisfying non-destructive testing methods to assess the current state of failure nor to estimate the level of degradation accurately and economically. At BAM division 3.5, analysing the ageing process of mobile composite
pressure vessels is a major task to ensure safe usage over the whole lifetime. In this context, key aspects of our ongoing research activities are the invention of new test procedures and the development of accurate lifetime prediction models. In order to determine the level of degradation
or damage, one meaningful non-destructive approach is to analyse the structural dynamic behaviour via an experimental modal analysis (EMA). Over the last few years, different types and sizes of composite pressure vessels have been tested in several research projects. The presented paper gives
an insight into how to extract and interpret modal parameters and how to fit them to the results of residual strength tests.
Strategies to enhance the attenuation band in finite beams using periodic attachments
Authors: Carneiro Jr. Jean
Published: November 2023

One-dimensional waveguides, such as beams are frequently found in structural engineering applications. A finite periodic structure composed of a beam with periodically spaced vibration absorbers is considered in this work. Additionally, the behaviour of the structure when a hinge condition
is imposed between adjacent cells is investigated. Based on the dynamic stiffness matrix approach, the transverse displacement transmissibility is evaluated for a single cell. The effectiveness of using appropriately tuned vibration absorbers in the formation of a smooth super attenuation
band is demonstrated. Prediction of the attenuation band is also discussed for a structure with several periodic cells. In addition, the effect of hinge connections between the cells on the boundary frequencies of the attenuation band and the minimum transmissibility is presented.
Application of acoustic metamaterial for tire noise reduction
Authors: Kronowetter Felix
Published: November 2023

Increased traffic volume leads to increased noise emitted by the vehicles. Additionally, the lightweight design of vehicles worsens the noise, vibrations and harshness behavior. The total noise of the vehicle consist of multiple sources. We focus on the influence of sound emitted by
the tire on the interior cabin noise and on the pass-by noise. To address the problem, we develop two different wheelhouse liners based on a compound material and an acoustic metamaterial, respectively. The compound material consists of porous layers as well as a microperforated panel. The
acoustic metamaterial relies on a periodic arrangement of local resonators. Both materials are numerically modeled and experimentally validated. We first measure the absorption coefficient of the liner in the Alpha Cabin. We then mount the liner to a vehicle and subsequently measure the performance
of the full vehicle. We achieve improved performance in terms of sound attenuation and thus are able to reduce both, the cabin noise and the pass-by noise, significantly.
A fast multipole boundary element method for acoustics in viscothermal fluids
Authors: Preuss Simone
Published: November 2023

Standard numerical models in acoustics rely on the isentropic Helmholtz equation. Its derivation assumes adiabatic and reversible, i.e., dissipation-free, wave propagation. Sound waves in fluids are, however, subject to viscous and thermal losses. These losses originate from viscous
friction and heat conduction, leading to the formation of acoustic boundary layers. Considering these effects becomes significant in setups with acoustic cavities of similar dimension as the boundary layers. Recently, boundary element methods (BEM) accounting for the viscothermal dissipation
have been proposed. These methods limit the discretization to the surface of the fluid domain and require significantly fewer degrees of freedom than comparable finite element models. However, the BEM coefficient matrices are fully populated, resulting in high computational costs and storage
requirements. This study develops a new BEM formulation for acoustics in viscothermal fluids that uses the fast multipole method - a low-rank approximation technique based on a hierarchical subdivision of the computational domain - to alleviate this shortcoming. It is shown that the fast viscothermal
BEM improves the algorithmic complexity over the conventional formulation, reducing both the memory requirements and solution time. The results indicate good scalability of the method making it feasible for larger applications such as acoustic metamaterials.
Analysis of thermoacoustic phenomenon using concentrated mass model
Authors: Funyu Daiki
Published: November 2023

In general acoustic analysis, temperature of the air is often assumed to be constant. However, in some cases, the relationship between sound waves and temperature cannot be ignored. For example, a temperature gradient in an acoustic tube can generate self-excited vibrations of the air.
A temperature gradient can also be generated by the input of sound waves. Engines and refrigerators that apply these phenomena can use exhaust heat as a drive source, so that they are expected as thermoacoustic devices with little adverse effect on the environment. Thermoacoustic devices have
been actively studied in recent years, and efficient analytical methods including non-linearity of sound waves are still required. In this study, we propose an analysis method of thermoacoustic phenomena using a concentrated mass model. This model consisted of masses, springs, and dampers,
and efficiently analyses thermoacoustic phenomena as a vibration system. In addition, this model is suitable for non-linear analysis and coupled analysis with other vibrating bodies. In this paper, we formulated an acoustic tube with a temperature gradient using the proposed model and verified
the validity of the model by numerical calculations.
Bloch mode synthesis for band-structure computation of unit cell with non-matching boundaries
Authors: Xi Chenyang
Published: November 2023

Bloch mode synthesis is an efficient method to calculate the band property of periodic structures, which involves the repeated solution of many eigenvalue problems on each wave vector around the Brillouin zone. It is based on projecting internal degrees of freedom (DOFs) of the unit
cell to the modal domain and keeping the boundary DOFs in the physical domain. While this transformation greatly reduces the model order of the unit cell, it leaves the question of how to impose the Floquet-Bloch boundary conditions when the boundary nodes are non-matching. In this paper,
an interpolation-based method is proposed to address the non-conformity problem, which consists of building a smooth function by interpolating the variables on the master boundary and determining the variables on the slave boundary by sampling that smooth function. This procedure creates an
interpolation matrix to connect the master and slave variables, which can be integrated into the original Bloch mode synthesis formulation to absolve the incompatibility caused by non-matching boundaries. The accuracy of the proposed method is verified using one non-conforming unit cell example
in the end.
The natural frequency estimation for a system composed of a beam and a spring-mass system
Authors: Sun Xutao
Published: November 2023

This study presents an approximate method for determining the natural frequency of a system composed of a beam and a two-degree-of-freedom spring-mass system. The expression for estimating the natural frequency is derived following the standard procedures of the forced vibration analysis
of a beam. The results obtained using the current method are in good agreement with those obtained through the dynamic stiffness method, especially when the spring stiffness is large. The innovativeness of the current method is that it reveals the relevance between the natural frequency of
the system, the natural frequency of the beam, and the mode shape data at the positions where the spring-mass system is attached to the beam. The method is potentially useful in the dynamic wheel-track interaction analysis because the train wheel is normally simplified as a spring-mass system
with high spring stiffness. It may also be applied to natural frequency-based damage detection where an auxiliary spring-mass system is used. When the spring-mass system roves on the beam, the curve of natural frequency versus spring-mass system location would be relevant to the mode shape
square which is sensitive to local damage.
Dispersion relation and sound transmission loss of a Mindlin plate with an array of attached masses
Authors: Sorokin Vladislav
Published: November 2023

The paper concerns increasing the sound transmission loss of wall partitions in the coincidence region by the addition of an array of point masses. Both theoretical and experimental analysis of sound and vibration attenuation in a Mindlin plate with masses attached in a periodic "supercell"
pattern are performed. Distances between the neighbouring masses within the supercell are not restricted to be equal, and masses themselves can be non-identical. By modelling the masses as point attachments, analytical expressions are developed for predicting the dispersion relation and frequency
bandgaps of the plate. It is shown that wave propagation in two primary (orthogonal) directions in the plate and the corresponding frequency bandgaps have the most pronounced effect on the sound transmission loss. Variation of the distances between the masses, or masses themselves, can lead
to additional lower-frequency bandgaps. The effects of the frequency bandgaps on the sound transmission through the plate are validated by numerical analysis conducted using the wave and finite element method. Experimental testing in a transmission suite under diffuse field conditions of large-scale
(2.4m by 1m) plates with periodically attached masses is conducted, showing benefits of utilizing multiple scattering to increase the sound transmission loss in the targeted region.
Uncertainty quantification of the diffuse sound field assumption in sound insulation predictions
Authors: Edwin Reynders
Published: November 2023

The transmission loss of a partition depends on the sound fields in the adjoining rooms, which are often taken to be diffuse. A diffuse sound field is a random field, representing a conceptual ensemble of rooms with the same volume and reverberation time, but otherwise any possible
arrangement of boundaries and small objects that have a wave scattering effect. Uncertainty due to random wave scattering is therefore inherently present in diffuse transmission loss values. In this work, closed-form expressions are presented for quantifying this uncertainty, such that it
becomes possible to estimate by how much the transmission loss of a particular room-wall-room system may deviate from the nominal, ensemble average value which corresponds to omnidirectional incidence and halfspace radiation. The first expression is exact yet its evaluation requires knowledge
of the dynamic stiffness of the partitioning structure and of the radiation impedances of the surrounding fluids. The second expression is approximate and depends on energetic quantities only, so it is also applicable in an experimental setting. The expressions are validated in a Monte-Carlo
simulation study involving a single wall.
Le langage imagé de la venue du règne de Dieu : Étude de Marc 4/1-34
Authors: Wagner Guy
Published: November 2023

Marc 4 a été écrit au moment de la défaite juive en 70. Guy Wagner pense que l'auteur a voulu, en composant ce chapitre, rendre compte de l'incrédulité des Juifs et stimuler le zèle des croyants. La prophétie mystérieuse d’Esaïe se réalise. Elle devient parabole de la semence dont la croissance va aboutir au grand arbre, signe du royaume.
L’univers né du vide
Authors: Andrillat Henri
Published: November 2023

Que nous dit l'astrophysique sur la naissance de l'univers ? Le professeur Henri Andrillat répond à cette question en faisant le point sur les recherches les plus récentes et en faisant apparaître de surprenantes correspondances avec des thèmes théologiques.
Luc et les christianismes primitifs
Authors: Cuvillier Elian
Published: November 2023

Le récit du livre des Actes des Apôtres laisse apparaître, derrière la présentation quelque peu idéalisée des origines de l’Eglise primitive, une diversité de courants théologiques. E. Cuvillier montre comment cette pluralité s’articule en particulier autour des figures de Pierre, Jacques et Paul.
La place de la Septante dans les études bibliques
Authors: Harl Marguerite
Published: November 2023

Les livres hébreux ont été traduits en grec par des Juifs de l’époque hellénistique. Leur version a été acceptée par une partie du judaïsme et reçue comme «Ancien Testament» dans le christianisme des premiers siècles. Marguerite Harl montre que cette réalité historique pose le problème de la «traductibilité» du texte sacré. Les traducteurs juifs, comme les traducteurs modernes de la Bible, ont cherché une voie légitime entre un strict littéralisme (parfois peu compréhensible) et une traduction qui rende compte du sens, sans que l’on puisse parler de déviation.
Les motifs de la rédaction de l’Épître aux Galates
Authors: Wagner Guy
Published: November 2023

Guy Wagner pense qu’il faut interpréter l’Epître en prenant à la lettre ce que Paul dit de la situation dans les derniers mots. Les gens qui veulent imposer la circoncision sont eux-mêmes des païens récemment convertis, qui croient trouver dans la circoncision un moyen de se rattacher à la religion juive reconnue licite par Rome. Paul combat non seulement le légalisme juif mais toute forme religieuse destinée à se protéger ou se valoriser.
Exister publiquement. Protestantisme et communication
Authors: Keller Paul
Published: November 2023

Le monde associatif, dont les Églises font partie, a longtemps joué un rôle de premier plan dans la mise en circulation des messages. Aujourd’hui, son type de communication sociale est dévalué par l’omniprésence des médias et la fascination qu’ils exercent.

A partir d’une étude de l’IFOP, Paul Keller cherche à repérer les principales questions que le protestantisme doit affronter, y compris en son sein, s’il veut être un meilleur communicant et prendre place dans l’espace public. Quelle communication et à quel prix ?
L’évangélisation est-elle encore possible ? A propos du télévangéliste américain Bob Schuller
Authors: Cochand Nicolas
Published: November 2023

Des Églises nord-américaines pratiquent la prédication chrétienne par le moyen de la télévision. Quels sont les messages, les valeurs, les techniques de cette évangélisation télévisuelle ? En s'appuyant sur l’exemple de Bob Schuller, Nicolas Cochand dépasse les clichés simplistes et pose la question de la mission de l'Église.
Parabolē dans la tradition synoptique
Authors: Cuvillier Elian
Published: November 2023

Dans cet article, Elian Cuvillier s’efforce de mettre en évidence les perspectives théologiques propres à Marc, Matthieu et Luc, à travers leur utilisation respective du concept de parabole.