bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of the dielectric barrier discharge plasma actuator in the control of non-reactive flow in a non-premixed bluff body burner
Authors: Khasare Sepideh , Bagherighajari Fatemeh , Dolati Farid , Mahmoudimehr Javad , Páscoa José , Abdollahzadehsangroudi Mohammadmahdi
Published: July 2023

Active flow control methods based on dielectric barrier discharge plasma actuators can be used to increase the efficiency of combustion systems. In this study, the influence of the location of plasma actuators on the bluff body in a non-premixed burner on the non-reactive flow field of fuel and oxidizer is investigated numerically. Flow field properties and spatial mixing deficiency (SMD) are calculated to evaluate the plasma actuator's influence on the reactants' mixing inside the burner. The results show that the plasma actuator can influence the recirculation areas and are effective in mixing fuel and oxidizer. The presence of the plasma actuator results in the formation of a vortex, which slows down the movement of the flow and improves the mixing between the fuel and airflow streams resulting in more favorable combustion. The results show that at a higher air velocity (4 m/s), the formation of a plasma zone near the air duct strengthens the external circulation zone (ERZ) in such a way that it surrounds the internal recirculation zone and reduces the value of SMD by an average of 7.89%. While activating the actuator also strengthens the ERZ for a lower air velocity (0.3 m/s), this affects the air inflow, and the flow field becomes dominated by the fuel jet flow. When the diameter of the bluff body is increased, both when the plasma actuator is active or inactive, the ERZ is greatly strengthened, and the flow field is more dominated by the airflow.
A numerical study of aeration characteristics of a plunging solitary wave on a slope
Authors: Tang Lian , Lin Pengzhi
Published: July 2023

In this paper, the characteristics of aerated flow under a plunging solitary wave on a 1:20 sloping beach are investigated numerically. The numerical model solves the Reynolds-averaged Navier–Stokes equations for mean flow. The turbulence is described by the k−ε model, in which the turbulence production and dissipation modified by entrained air bubbles are considered by an additional term. A transient equation is solved for air bubble transportation. The numerical model is validated by comparing the air bubble concentration, mean flow velocities, and turbulent kinetic energy against experimental data, demonstrating its capability for simulating transient aerated flows under breaking waves. The validated model is further applied to reveal the detailed interaction of the entrained air bubbles and the turbulent free surface flows during the wave breaking process. Plunging breaking wave consists of four stages, namely, the wave front steepening, the initiation of overturning, the transitional stage, and the quasi-steady bore propagation stage. The results reveal that the overturning and breaking wave front is the main source for turbulence generation and air entrainment in the initiation and transitional stage of breaking wave, respectively. The entrained air bubbles are mainly transported backward and downward by turbulence structures and forming distinct bubble vortex rollers near the bottom. The distribution of air bubble concentration shows a linear correlation to the distribution of turbulence quantities in the initial and transitional stage of breaking wave, demonstrating the important role of local turbulent structures on air entrainment and transportation.
Transport coefficients for ion and solvent coupling. The case of the lithium-ion battery electrolyte
Authors: Kjelstrup Signe , Gunnarshaug Astrid Fagertun , Gullbrekken Øystein , Schnell Sondre K. , Lervik Anders
Published: July 2023

Transport properties are essential for the understanding and modeling of electrochemical cells, in particular complex systems like lithium-ion batteries. In this study, we demonstrate how a certain degree of freedom in the choice of variables allows us to efficiently determine a complete set of transport properties. We apply the entropy production invariance condition to different sets of electrolyte variables and obtain a general set of formulas. We demonstrate the application of these formulas to an electrolyte typical for lithium-ion batteries, 1M lithium hexafluoro-phosphate in a 1:1 wt. % mixture of ethylene and diethyl carbonates. While simplifications can be introduced, they provide inadequate predictions of conductivity and transport numbers, and we argue that a full matrix of Onsager coefficients is needed for adequate property predictions. Our findings highlight the importance of a complete set of transport coefficients for accurate modeling of complex electrochemical systems and the need for careful consideration of the choice of variables used to determine these properties.
Elastic softening and hardening at intersections between twin walls and surfaces in ferroelastic materials
Authors: He Xiaomei , Ding Xiangdong , Sun Jun , Nataf Guillaume F. , Salje Ekhard K. H.
Published: July 2023

Surfaces play a key role during ferroelastic switching and define the interactions of materials with ionic species and biological systems. Here, we perform molecular dynamics simulations and identify ridges and valleys with rounded singularities around the intersections between twin walls and surfaces. Two dominant length scales stem from the elastic bending of the surface layer (>30 lattice units) and local atomic reshuffles (some five lattice units). For static twin walls, which do not shift laterally under external stress, the intrinsic change in Young’s modulus involves softening near valleys and hardening near ridges. The boundary-induced changes in the surface Young’s modulus are of the order of 0.7%.
Connections and performances of Green’s function methods for charged and neutral excitations
Authors: Monino Enzo , Loos Pierre-François
Published: July 2023

In recent years, Green’s function methods have garnered considerable interest due to their ability to target both charged and neutral excitations. Among them, the well-established GW approximation provides accurate ionization potentials and electron affinities and can be extended to neutral excitations using the Bethe–Salpeter equation (BSE) formalism. Here, we investigate the connections between various Green’s function methods and evaluate their performance for charged and neutral excitations. Comparisons with other widely known second-order wave function methods are also reported. Additionally, we calculate the singlet-triplet gap of cycl[3,3,3]azine, a model molecular emitter for thermally activated delayed fluorescence, which has the particularity of having an inverted gap thanks to a substantial contribution from the double excitations. We demonstrate that, within the GW approximation, a second-order BSE kernel with dynamical correction is required to predict this distinctive characteristic.
The transport performance of condensate droplets on inclined superhydrophobic surfaces
Authors: Hou Huimin , Wu Xiaomin , Hu Zhifeng , Gao Sihang , Yuan Zhiping
Published: July 2023

Coalescence-induced droplet jumping on superhydrophobic surfaces has significant potential for various applications, such as enhanced condensation, water harvesting, self-cleaning, and thermal management of electronic devices. Existing research focuses primarily on the coalescence and jumping of two or more droplets on the horizontally placed superhydrophobic surface, but the transport behavior of condensate droplets caused by coalescence-induced jumping on the inclined superhydrophobic surface is insufficiently understood. In this work, we investigate the impact of the surface inclination angle on the dynamic behavior of condensate droplets and derive the relationship between the transport distance, transport height, jumping direction of droplets, and the surface inclination angle. Additionally, we establish a droplet motion equation to describe the trajectory of droplets after they jump off the surface. Furthermore, we demonstrate the phenomenon of multi-hop jumping on the inclined superhydrophobic surface, which can increase the droplet transport distance, and the established mathematical model can better predict the multi-hop jumping transport distance. This work exposes the effect of superhydrophobic surface inclination angle on droplet dynamics and droplet directional transport performance, which has significant implications for the application of droplet jumping.
Dynamical low-noise microwave source for cold-atom experiments
Authors: Meyer-Hoppe Bernd , Baron Maximilian , Cassens Christophe , Anders Fabian , Idel Alexander , Peise Jan , Klempt Carsten
Published: July 2023

The generation and manipulation of ultracold atomic ensembles in the quantum regime require the application of dynamically controllable microwave fields with ultra-low noise performance. Here, we present a low-phase-noise microwave source with two independently controllable output paths. Both paths generate frequencies in the range of 6.835 GHz ± 25 MHz for hyperfine transitions in 87Rb. The presented microwave source combines two commercially available frequency synthesizers: an ultra-low-noise oscillator at 7 GHz and a direct digital synthesizer for radio frequencies. We demonstrate a low integrated phase noise of 480 µrad in the range of 10 Hz to 100 kHz and fast updates of frequency, amplitude, and phase in sub-µs time scales. The highly dynamic control enables the generation of shaped pulse forms and the deployment of composite pulses to suppress the influence of various noise sources.
Contraction of infinite-long air sheet at capillary-inertial regime
Authors: Jian Zhen , Li Ruixuan , Guo Jiaojiao
Published: July 2023

The contraction of a two-dimensional infinite-long flat air sheet in a liquid environment at a capillary-inertial regime with an Ohnesorge number Oh ⩽ 0.01 was investigated numerically. The contraction velocity first increases to a maximum and then decreases and follows a scaling U*∼t*−0.2. In this range of Oh number, pinch-off and oscillation were always observed, and two pinch-off mechanisms were identified as end-pinching (Oh ⩽ 0.006) and oscillation-induced pinch-off (Oh ⩾ 0.007), which also correspond to two oscillation regimes of the rim. Different modes of vortex shedding and merging, co-rotating, and separation of vortices are observed; the interaction between the rim and the vortices is responsible for the complicated contraction dynamics.
Importance of circadian rhythms in dairy nutrition
Authors: Harvatine Kevin J.
Published: July 2023

Biological rhythms are repeating patterns that are driven by time-keeping mechanisms within the animal and are adaptive as they coordinate physiology and metabolism with the external environment. The dairy cow has a well recognised natural daily pattern of feed intake and milk synthesis, but regulation of these rhythms has not been well described in the literature or well considered in current dairy management. Recent discoveries have clearly described circadian time-keeping mechanisms in peripheral tissues that are responsive to the timing of food availability. Some management strategies on dairy farms may desynchronise the interactions between central and mammary circadian timekeepers, resulting in reduced milk yield and efficiency. Feeding a total mixed ration is commonly assumed to create constant ruminal conditions, but the large variation in the rate of feed intake across the day causes large fluctuations in rumen fermentation and absorbed nutrients. Milk composition also differs across the day due to both dynamics in nutrient absorption and biological regulation attempting to match milk yield and composition with calf requirements across the day. Recent work has shown that milk synthesis varies over the day and is modified by the timing of feed intake and nutrient absorption. These rhythms have also been shown to be affected by the timing of feed delivery. We expect that maximal milk yield and efficiency are achieved when we have more consistent rumen fermentation and match the timing of nutrient absorption and mammary capacity for milk synthesis. Managing feeding times provides the opportunity to modify feed intake across the day, but behavioural responses are complex. Appreciating the impact of circadian rhythms provides the foundation to develop nutrition and management strategies considering circadian dynamics of intake and milk synthesis and provides opportunities for new gains in cow efficiency, welfare, and health.
Membrane stretch as the mechanism of activation of PIEZO1 ion channels in chondrocytes
Authors: Savadipour Alireza , Nims Robert J. , Rashidi Neda , Garcia-Castorena Jaquelin M. , Tang Ruhang , Marushack Gabrielle K. , Oswald Sara J. , Liedtke Wolfgang B. , Guilak Farshid
Published: July 2023

Osteoarthritis is a chronic disease that can be initiated by altered joint loading or injury of the cartilage. The mechanically sensitive PIEZO ion channels have been shown to transduce injurious levels of biomechanical strain in articular chondrocytes and mediate cell death. However, the mechanisms of channel gating in response to high cellular deformation and the strain thresholds for activating PIEZO channels remain unclear. We coupled studies of single-cell compression using atomic force microscopy (AFM) with finite element modeling (FEM) to identify the biophysical mechanisms of PIEZO-mediated calcium (Ca
2+
) signaling in chondrocytes. We showed that PIEZO1 and PIEZO2 are needed for initiating Ca
2+
signaling at moderately high levels of cellular deformation, but at the highest strains, PIEZO1 functions independently of PIEZO2. Biophysical factors that increase apparent chondrocyte membrane tension, including hypoosmotic prestrain, high compression magnitudes, and low deformation rates, also increased PIEZO1-driven Ca
2+
signaling. Combined AFM/FEM studies showed that 50% of chondrocytes exhibit Ca
2+
signaling at 80 to 85% nominal cell compression, corresponding to a threshold of apparent membrane finite principal strain of E = 1.31, which represents a membrane stretch ratio (λ) of 1.9. Both intracellular and extracellular Ca
2+
are necessary for the PIEZO1-mediated Ca
2+
signaling response to compression. Our results suggest that PIEZO1-induced signaling drives chondrocyte mechanical injury due to high membrane tension, and this threshold can be altered by factors that influence membrane prestress, such as cartilage hypoosmolarity, secondary to proteoglycan loss. These findings suggest that modulating PIEZO1 activation or downstream signaling may offer avenues for the prevention or treatment of osteoarthritis.
Global impacts of recent Southern Ocean cooling
Authors: Kang Sarah M. , Yu Yue , Deser Clara , Zhang Xiyue , Kang In-Sik , Lee Sun-Seon , Rodgers Keith B. , Ceppi Paulo
Published: July 2023

Since the beginning of the satellite era, Southern Ocean sea surface temperatures (SSTs) have cooled, despite global warming. While observed Southern Ocean cooling has previously been reported to have minimal impact on the tropical Pacific, the efficiency of this teleconnection has recently shown to be mediated by subtropical cloud feedbacks that are highly model-dependent. Here, we conduct a coupled model intercomparison of paired ensemble simulations under historical radiative forcing: one with freely evolving SSTs and the other with Southern Ocean SST anomalies constrained to follow observations. We reveal a global impact of observed Southern Ocean cooling in the model with stronger (and more realistic) cloud feedbacks, including Antarctic sea–ice expansion, southeastern tropical Pacific cooling, northward-shifted Hadley circulation, Aleutian low weakening, and North Pacific warming. Our results therefore suggest that observed Southern Ocean SST decrease might have contributed to cooler conditions in the eastern tropical Pacific in recent decades.
Immunization with lytic polysaccharide monooxygenase CbpD induces protective immunity against
Pseudomonas aeruginosa
pneumonia
Authors: Askarian Fatemeh , Tsai Chih-Ming , Cordara Gabriele , Zurich Raymond H. , Bjånes Elisabet , Golten Ole , Vinther Sørensen Henrik , Kousha Armin , Meier Angela , Chikwati Elvis , Bruun Jack-Ansgar , Ludviksen Judith Anita , Choudhury Biswa , Trieu Desmond , Davis Stanley , Edvardsen Per Kristian Thorén , Mollnes Tom Eirik , Liu George Y. , Krengel Ute , Conrad Douglas J. , Vaaje-Kolstad Gustav , Nizet Victor
Published: July 2023

Pseudomonas aeruginosa
(PA) CbpD belongs to the lytic polysaccharide monooxygenases (LPMOs), a family of enzymes that cleave chitin or related polysaccharides. Here, we demonstrate a virulence role of CbpD in PA pneumonia linked to impairment of host complement function and opsonophagocytic clearance. Following intratracheal challenge, a PA ΔCbpD mutant was more easily cleared and produced less mortality than the wild-type parent strain. The x-ray crystal structure of the CbpD LPMO domain was solved to subatomic resolution (0.75Å) and its two additional domains modeled by small-angle X-ray scattering and Alphafold2 machine-learning algorithms, allowing structure-based immune epitope mapping. Immunization of naive mice with recombinant CbpD generated high IgG antibody titers that promoted human neutrophil opsonophagocytic killing, neutralized enzymatic activity, and protected against lethal PA pneumonia and sepsis. IgG antibodies generated against full-length CbpD or its noncatalytic M2+CBM73 domains were opsonic and protective, even in previously PA-exposed mice, while antibodies targeting the AA10 domain were not. Preexisting antibodies in PA-colonized cystic fibrosis patients primarily target the CbpD AA10 catalytic domain. Further exploration of LPMO family proteins, present across many clinically important and antibiotic-resistant human pathogens, may yield novel and effective vaccine antigens.
Multiscale analysis of Benjamin Franklin’s innovations in American paper money
Authors: Manukyan Khachatur , Yeghishyan Armenuhi , Aprahamian Ani , Jordan Louis , Kurkowski Michael , Raddell Mark , Richter Le Laura , Schultz Zachary D. , Spillane Liam , Wiescher Michael
Published: July 2023

Benjamin Franklin was a preeminent proponent of the new colonial and Continental paper monetary system in 18th-century America. He established a network of printers, designing and printing money notes at the same time. Franklin recognized the necessity of paper money in breaking American dependence on the British trading system, and he helped print Continental money to finance the American War of Independence. We use a unique combination of nondistractive, microdestructive, and advanced atomic-level imaging methods, including Raman, Infrared, electron energy loss spectroscopy, X-ray diffraction, X-ray fluorescence, and aberration-corrected scanning transmission electron microscopy, to analyze pre-Federal American paper money from the Rare Books and Special Collections of the Hesburgh Library at the University of Notre Dame. We investigate and compare the chemical compositions of the paper fibers, the inks, and fillers made of special crystals in the bills printed by Franklin’s printing network, other colonial printers, and counterfeit money. Our results reveal previously unknown ways that Franklin developed to safeguard printed money notes against counterfeiting. Franklin used natural graphite pigments to print money and developed durable “money paper” with colored fibers and translucent muscovite fillers, along with his own unique designs of “nature-printed” patterns and paper watermarks. These features and inventions made pre-Federal American paper currency an archetype for developing paper money for centuries to come. Our multiscale analysis also provides essential information for the preservation of historical paper money.
A variant-dependent molecular clock with anomalous diffusion models SARS-CoV-2 evolution in humans
Authors: Goiriz Lucas , Ruiz Raúl , Garibo-i-Orts Òscar , Conejero J. Alberto , Rodrigo Guillermo
Published: July 2023

The evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in humans has been monitored at an unprecedented level due to the public health crisis, yet the stochastic dynamics underlying such a process is dubious. Here, considering the number of acquired mutations as the displacement of the viral particle from the origin, we performed biostatistical analyses from numerous whole genome sequences on the basis of a time-dependent probabilistic mathematical model. We showed that a model with a constant variant-dependent evolution rate and nonlinear mutational variance with time (i.e., anomalous diffusion) explained the SARS-CoV-2 evolutionary motion in humans during the first 120 wk of the pandemic in the United Kingdom. In particular, we found subdiffusion patterns for the Primal, Alpha, and Omicron variants but a weak superdiffusion pattern for the Delta variant. Our findings indicate that non-Brownian evolutionary motions occur in nature, thereby providing insight for viral phylodynamics.
Homeostatic regulation of ribosomal proteins by ubiquitin-independent cotranslational degradation
Authors: Ju Donghong , Li Li , Xie Youming
Published: July 2023

Ribosomes are the workplace for protein biosynthesis. Protein production required for normal cell function is tightly linked to ribosome abundance. It is well known that ribosomal genes are actively transcribed and ribosomal messenger RNAs (mRNAs) are rapidly translated, and yet ribosomal proteins have relatively long half-lives. These observations raise questions as to how homeostasis of ribosomal proteins is controlled. Here, we show that ribosomal proteins, while posttranslationally stable, are subject to high-level cotranslational protein degradation (CTPD) except for those synthesized as ubiquitin (Ub) fusion precursors. The N-terminal Ub moiety protects fused ribosomal proteins from CTPD. We further demonstrate that cotranslational folding efficiency and expression level are two critical factors determining CTPD of ribosomal proteins. Different from canonical posttranslational degradation, we found that CTPD of all the ribosomal proteins tested in this study does not require prior ubiquitylation. This work provides insights into the regulation of ribosomal protein homeostasis and furthers our understanding of the mechanism and biological significance of CTPD.
Class I histone deacetylase complex: Structure and functional correlates
Authors: Wang Xiao , Wang Yannan , Liu Simiao , Zhang Yi , Xu Ke , Ji Liting , Kornberg Roger D. , Zhang Heqiao
Published: July 2023

The
Schizosaccharomyces pombe
Clr6S complex, a class I histone deacetylase complex, functions as a zinc-dependent enzyme to remove acetyl groups from lysine residues in histone tails. We report here the cryo-EM structure of Clr6S alone and a cryo-EM map of Clr6S in complex with a nucleosome. The active center, revealed at near-atomic resolution, includes features important for catalysis—A water molecule coordinated by zinc, the likely nucleophile for attack on the acetyl-lysine bond, and a loop that may position the substrate for catalysis. The cryo-EM map in the presence of a nucleosome reveals multiple Clr6S–nucleosome contacts and a high degree of relative motion of Clr6S and the nucleosome. Such flexibility may be attributed to interaction at a site in the flexible histone tail and is likely important for the function of the deacetylase, which acts at multiple sites in other histone tails.
Unlicensed origin DNA melting by MCV and SV40 polyomavirus LT proteins is independent of ATP-dependent helicase activity
Authors: Wan Li , Toland Sabrina , Robinson-McCarthy Lindsey R. , Lee Nara , Schaich Matthew A. , Hengel Sarah R. , Li Xiaochen , Bernstein Kara A. , Van Houten Bennett , Chang Yuan , Moore Patrick S.
Published: July 2023

Cellular eukaryotic replication initiation helicases are first loaded as head-to-head double hexamers on double-stranded (ds) DNA origins and then initiate S-phase DNA melting during licensed (once per cell cycle) replication. Merkel cell polyomavirus (MCV) large T (LT) helicase oncoprotein similarly binds and melts its own 98-bp origin but replicates multiple times in a single cell cycle. To examine the actions of this unlicensed viral helicase, we quantitated multimerization of MCV LT molecules as they assembled on MCV DNA origins using real-time single-molecule microscopy. MCV LT formed highly stable double hexamers having 17-fold longer mean lifetime (τ, >1,500 s) on DNA than single hexamers. Unexpectedly, partial MCV LT assembly without double-hexamer formation was sufficient to melt origin dsDNA as measured by RAD51, RPA70, or S1 nuclease cobinding. DNA melting also occurred with truncated MCV LT proteins lacking the helicase domain, but was lost from a protein without the multimerization domain that could bind only as a monomer to DNA. SV40 polyomavirus LT also multimerized to the MCV origin without forming a functional hexamer but still melted origin DNA. MCV origin melting did not require ATP hydrolysis and occurred for both MCV and SV40 LT proteins using the nonhydrolyzable ATP analog, adenylyl-imidodiphosphate (AMP-PNP). LT double hexamers formed in AMP-PNP, and melted DNA, consistent with direct LT hexamer assembly around single-stranded (ss) DNA without the energy-dependent dsDNA-to-ssDNA melting and remodeling steps used by cellular helicases. These results indicate that LT multimerization rather than helicase activity is required for origin DNA melting during unlicensed virus replication.
Mechanical fault diagnosis based on deep transfer learning: a review
Authors: Yang Dalian , Zhang Wenbin , Jiang Yongzheng
Published: July 2023

Mechanical fault diagnosis is an important method to accurately identify the health condition of mechanical equipment and ensure its safe operation. With the advent of the era of ‘big data’, it is an inevitable trend to choose deep learning for mechanical fault diagnosis. At the same time, to improve the generalization ability of deep learning applications in different scenarios of fault diagnosis, mechanical diagnosis based on transfer learning has also been proposed and become an important branch in the field of mechanical fault diagnosis. This paper introduces the principle of transfer learning, summarizes the research and application of transfer learning in the field of fault diagnosis, discusses the shortcomings of transfer learning in the field of fault diagnosis, and discusses the future research direction of transfer learning in the field of fault diagnosis.
Bioimpedance spectroscopy measurement method based on multisine excitation and integer-period undersampling
Authors: Li Wensheng , Shi Hong , Zhang Luping , Bai Wenqi , Wu Shuangshuang , Zhang Fu , Yang Yuxiang
Published: July 2023

Bioimpedance spectroscopy (BIS) is a detection technology that uses the bioimpedance characteristics of human tissues and their changes to analyze their physiological and pathological status, and is widely used in clinical and scientific research applications. Traditional BIS measurement must satisfy the Nyquist sampling theorem so as to ensure that the measurement signal has no frequency aliasing, but at the same time the sampling frequency and the number of sampling points will be increased, which will increase the computation and hardware costs. This paper proposes a novel BIS measurement method based on multisine excitation and integer-period undersampling (IPUS) technology. Firstly, the multisine-based IPUS theory is deduced, and the BIS measurement principle based on multisine excitation and IPUS technology is introduced. Secondly, a BIS measurement system based on a field-programmable gate array + analog-to-digital converter + digital-to-analog converter architecture is designed, and multisine excitation with 32 pseudo-logarithmically distributed frequency components in the range of 2–997 kHz is generated. Comparative BIS measurement experiments on three RC three-element models are carried out under the Nyquist sampling condition (sampling frequency fs
= 2.56 MHz) and under the IPUS condition (fs
= 512 kHz), respectively. Experimental results show that the mean amplitude error of BIS measurement under the Nyquist sampling condition is 0.80% (±1.19% SD), while the mean amplitude error under the IPUS condition is 1.02% (±1.13% SD). Moreover, the signal-to-noise ratio (SNR
z
) is calculated in 40 repeated BIS measurements, where the mean SNR
z
is 63.60 dB under the IPUS condition, similar to the value of 62.77 dB under the Nyquist sampling condition. The proposed multisine-based IPUS theory and its implementation method in this paper can complete a BIS measurement with only one fundamental period, and the sampling frequency and sampling point requirements are lower than for Nyquist sampling, laying a theoretical and technical foundation for a BIS measurement system with reduced hardware and computation requirements.
LGMA-DRSN: a lightweight convex global multi-attention deep residual shrinkage network for fault diagnosis
Authors: Zhang Zhijin , Zhang Chunlei , Chen Lei , Li He , Han Ping
Published: July 2023

Recently, the fault diagnosis domain has witnessed a surge in the popularity of the deep residual shrinkage network (DRSN) due to its robust denoising capabilities. In our previous research, an enhanced version of DRSN named global multi-attention DRSN (GMA-DRSN) is introduced to augment the feature extraction proficiency of DRSN specifically for noised vibration signals. However, the utilization of multiple attention structures in GMA-DRSN leads to an escalation in the computational complexity of the network, which may pose practical deployment challenges. To address this limitation, this paper proposes a lightweight variant of GMA-DRSN, referred to as lightweight convex global multi-attention deep residual shrinkage network (LGMA-DRSN), building upon our prior work. Firstly, the numerical variation regularity of the adaptive inferred slope parameters in the global parametric rectifier linear unit is analyzed, where we surprisingly find that a convex parameter combination always occurs in pairs. Based on this convex regularity, the sub-network structure of the adaptive inferred slope with attention mechanism is optimized, which greatly reduces the computational complexity compared to our previous work. Finally, the experimental outcomes demonstrate that LGMA-DRSN not only enhances diagnostic efficiency, but also ensures a high level of diagnostic accuracy in the presence of noise interference, when compared with our prior work.
Laser ranging method based on dual-threshold echo pulse prediction and correction
Authors: Liu Zijian , Tao Min , Yu Qi , Song Junfeng , Gao Zhen , Su Gang , Wang Ziming , Li Chengming
Published: July 2023

In order to improve the accuracy of pulse laser ranging based on time-of-flight (TOF), this paper proposes a laser ranging method based on double threshold echo pulse prediction correction. By using two high-speed comparators with different thresholds to detect the pulse-echo signal, the initial TOF, pulse width, and edge rate can be obtained. These three parameters are combined with statistical functions to accurately predict the peak position of the echo pulse and obtain the corrected TOF. Finally, the accurate measurement distance is calculated. In the aspect of improving ranging accuracy, this method overcomes the shortcoming that the traditional TOF pulse laser rangefinder has large errors in measuring targets with different reflectivity. This method only uses two high-speed comparators and a monostable trigger more than traditional TOF laser ranging systems. Adding these simple circuits can greatly improve the accuracy of laser ranging. The system structure is simple and the cost is low. Experimental results show that this method can achieve accurate distance measurement, and the measurement error is significantly reduced. This method can greatly improve the performance of the TOF laser rangefinder.
Research on bolt looseness monitoring based on electromechanical impedance transmissibility technology
Authors: Yu Hui , Guo Chenguang , Li Nanqi , Lu Shengdong
Published: July 2023

Centralized damage, such as bolt looseness, is one of the most common types of damage in bridge structures. Thus, early detection of such damage is essential for bridge maintenance. Detection methods based on transmittance functions (TFs) have been widely studied. These functions use a T matrix to calculate damage indicators and reflect changes in dynamic parameters, such as natural structural frequencies. However, existing research has shown that the excitation position significantly impacts the T matrix. Therefore, this study proposes a new method based on electromechanical impedance (EMI) for local damage characterization, namely, EMI-TF. A series of comparative tests shows that the EMI-TF process is more sensitive and accurate than the traditional TFs. In addition, the sensitivity of the EMI-TF and EMI methods is compared. Results show that using EMI-TF technology can achieve the localization of minor damage at lower frequencies, which, to some extent, overcomes the limitations of the traditional EMI method that can only detect minor damage at high frequencies. The repeatability of EMI-TF is also studied separately in experiments, with ten repeated experiments conducted. Results show that the experimental results of EMI-TF have high repeatability.
Synchronization in the two networks-frustrated coupled oscillators with a noisy attractive-repulsive frequencies
Authors: Yasmine Benmesbah , Li Yongge , Jia Wantao , Xu Yong
Published: July 2023

We investigate the correlation effects of the two networks combined with an attractive-repulsive frequency altered by noise on the mutual synchronization of the two coupled Kuramoto models with parametric random phase-shift properties. The necessity and significance of collective behavior between ensembles of interacting oscillators and their rich phenomenology offer an idealization of several disciplines in which mutual synchronization competes with force. In this paper, we derive the phase-locked states and identify the significant synchronization transition points analytically with exact boundary conditions for the correlated and uncorrelated joint distributions, their stability, and bifurcation diagrams. We find that a perfect and imperfect supercritical to subcritical Hopf bifurcation transition occurs depending on the synchronic transition points for the correlated cases, characterized by the power scales and the largest eigenvalues of the networks. Moreover, we show the powerful interplay of force, noise, frustration, and network on the synchronization transitions of the two populations and their compromise between the correlated and uncorrelated joint probability distributions. The intensity and transmissibility of noise, in particular, vary within and between populations.
Research regarding water and methanol injection upon the physical parameters of emissions’ concentration values on a compression ignition engine
Authors: Suciu C C , Igreţ S V , Ionel I
Published: July 2023

The objective of this paper is to investigate the possibility of lowering pollution and improving the characteristics of a compression ignition engine for both stand-alone and hybrid-electric powered vehicles. Due to the necessity for lowering the output of nitrogen oxides and carbon monoxide emissions concentrations on compression ignition engines, the research focuses on the addition of water injection. A benefit is the active cooling of the combustion to increase the boost pressure is revealed. Ignition timing can be increased to higher values, safety, without exposing the engine to higher thermal load. Specific fuel consumption is also decreased due to the lower value of the existing and final attested by the exhaust gas temperature.
The importance of the metal reinforcement of low voltage cables in the process of identifying defects
Authors: Predus M F , Muscai C M , Popescu C , Hatiegan C
Published: July 2023

Regarding the identification of defect in the electrical energy cables, in exploatation, usual or high-performance methods are used, based in particular on the phenomenon of reflection and refraction of the impulse transmitted in the cable, phenomenon generated by the impedance change at the defect location. In order to identify the defect, an important role is played by the existence of a current path on the cable route between the ends of the electrical cable and the place where the defect occurred. In the case of low voltage cables, there are situations where, following the sleeve process the continuity of the mechanical protection armature of the steel strip or the copper screen has not been restored. To measure the distance to the defect location, location equipment uses low and high voltage pulses which moves to the defect site with a certain speed and which is repeated after a selected time interval. These impulses are transmitted to the location of the defect at one end of the cable, through the circuit generated by the short circuit between the faulted conductor and the metal armature, which is usually found at ground potential. At the same time, there is situations where the defect is difficult to identify precisely because of the continuity of the reinforcement or screen and their connection to ground potential. This paper describes the stages of fault identification in a low-voltage power cable and presents a case study that highlights the importance of the metal reinforcement in the case of the high-voltage impulse method. Ways to detect defects using the arc reflected method (ARM) using the shock wave generator as well as the inductive method are also briefly presented.
Xilinx control circuit made to highlight injected fuel flow
Authors: Baciu I , Cunţan C D , Popa G N , Iagar A
Published: July 2023

The paper presents a control circuit made in Xilinx and which allows the adjustment of the frequency and the duty cycle of the control signal of an injector. The control circuit contains an oscillator and a selection circuit that provide specific commands to a counter. The oscillator that provides the clock frequency of a counting circuit uses the Nexis 4 DDR module’s own frequency. This is to be divided to the desired value by means of a divider implemented soft which makes changing the frequency easy. The signal obtained at its output commands a counter at which the maximum value of numbers is changed by a circuit selection. Thus, the variable duty cycle of the output signal of the development board is obtained, which is amplified both in voltage and in current, for compatibility with the injector parameters. The paper presents waveform obtained when resistive load operation as well as quantities of fuel injected in a given time interval.
Stereo vision based robot welding
Authors: Erceg D , Knezevic B Z , Grahovac Z
Published: July 2023

The most important advantages of robotic welding are precision and productivity. Introducing visual systems in welding allows one to easily position the elements that are welded. The robot will then perform welding without error after recording the welding points. The application of visual systems in robotics is very important because it enables the autonomous work of the robot. Stereo vision is used for three-dimensional reconstruction of the robot’s environment based on images captured by cameras. The stereo system consists of two cameras and a computer that processes the recorded images using appropriate programs and algorithms. The accuracy of estimating coordinates in space using a visual system is very important, it is necessary to estimate the parameters of the cameras and define their dependence. The relationship between the two cameras, as well as their basic parameters, are assessed by camera calibration. After calibrating the camera for each 2D coordinate, obtained from the camera sensor, it is possible to determine which set of points it belongs to in the 3D coordinate system. One of the most important and most difficult problems in the reconstruction of a 3D object is finding points on the planes of images that were created from the same physical point. The problem of correspondent points is also considered in this paper. To present the efficiency and reliability of the proposed solution for obtaining 3D coordinates of points in space, the proposed solution was tested in the laboratory and satisfactory results are obtained.
Digital tools for production planning as part of decision-making processes in the manufacturing systems
Authors: Matusova M , Ruzarovsky R , Delgado Sobrino D R , Hruskova E
Published: July 2023

The concept of digitalisation is making inroads into all areas of production systems as part of Industry 4.0. In our case, we are dealing specifically with the digital planning of production resources and production processes. Digitized solutions are included in this paper as case studies. Our goal was to develop digital models of manufacturing systems and simulation models for manufacturing processes in the Witness Horizon digital simulation environment. Simulation can be considered as one of the technologies used in the digital factory concept. It is a powerful tool that is often used for the design and analysis of complex systems. Decisions about a system are made through the construction of its computer models and experimentation on the models.
Measurement of strain and determination of stress state using a multi-chamber vertical cylindrical tank model
Authors: Islamović F , Bajramović E , Bajramović E , Bajramović E
Published: July 2023

Designing a new construction of large-volume multi-chamber tanks or converting existing single-chamber tanks into multi-chamber for storage of various types of petroleum products is a very demanding and responsible job, from the aspect of strain-stress analysis and the need to ensure structural integrity. From a wide range of conducted theoretical and experimental-numerical research, this paper singles out the applied method of similarity mechanics. The research was performed on a model of a four-chamber tank with dimensions reduced by 20 times (1:20) in relation to the real tank, made of steel sheets of quality S.0361. During the cold-water pressure test on the tank model (hydro test), the change of strain and stress state was monitored in the zones that were defined as critical by the preliminary numerical analysis by the finite element method (FEM). The results of these measurements, along with other reliable methods, can be very useful in the design of multi-chamber tanks with 5.000 m3 volume.
Dynamic study through numerical simulations of MacPherson suspension and static analysis of shock absorber components
Authors: Preda C , Bleotu R M , Pinca-Bretotean C
Published: July 2023

A suspension or shock absorber system is a mechanical device that is designed to attenuate or reduce the shock impulse and kinetic energy due to level differences or obstacles encountered by the car. In a vehicle structure, the shock absorber reduces the effect of driving on rough terrain, which automatically leads to improved driving quality and also increases passenger comfort.

The purpose of this dynamic study by numerical simulations of the MacPherson strut suspension is to highlight the dynamic differences between the stock and heavy MacPherson suspension duty for the Volkswagen Jetta, because it is the most common type of suspension on vehicles, and it is not complex in terms of operation.

The study was carried out only at the simulation stage in the MSC ADAMS program, for the dynamic analysis of the component parts, later the second phase of the research will propose the study on a real system.

One of the specific objectives of the paper is to compare the two types of springs, the stock with which the car is equipped at the factory and the modified one, the heavy duty variant (package heavy roads).

The second specific objective is to compare the two types of springs in relation to the two heights of the speed limiter and the two types of tires.

The third objective of this paper is to perform a comparative analysis of the main components of a shock absorber assembly, statically through tests in the ABAQUS simulation program.

Later, the results obtained after the analyzes indicated that the heavy duty type suspension has a higher degree of force attenuation. The end of the study was focused on the finite element analysis of the main components of a shock absorber in a suspension, analyzed from a static point of view.
Influence of thermal stresses on the phenomenon of thermal fatigue of rolling cylinders
Authors: Pinca-Bretotean C , Josan A , Sharma Arun Kumar
Published: July 2023

Hot rolling cylinders are the most important machine parts in plastic deformation equipment. They are taken out of operation due to breakage caused by the predominant action of thermal stresses which cause accidental breakdowns of rolling mills. In view of these aspects, the question arose is to knowing the nature of these stresses, as well as their evaluation. This paper will experimentally determine the mechanical and thermal stresses that arise in the process of plastic deformation of hot rolling cylinders. The purpose of this paper is to evaluate the thermal stresses and compare them with the mechanical ones, as well as to highlight their influence on the thermal fatigue phenomenon. The study shows that the stresses in rolling cylinders are cyclical and occur at each rotation of the cylinders. The thermal stresses are mainly the result of the action of symmetric and asymmetric temperature fields. The overall action of thermal stresses presents an aspect of destruction of the surface layer that characterizes the effect of thermal fatigue phenomenon. The separation of the temperature fields that produce thermal stresses in symmetric and asymmetric and their experimental confirmation represents the originality of the research presented in this paper.
Development of the structure and methodological support of the system for analysis of the details shaping using the technological inheritability of their quality parameters
Authors: Kusyi Ya M , Onysko O R , Kuk A M , Kostiuk O S , Solohub B V
Published: July 2023

Theoretical approaches, computer modell methods and experimental studies analyse the state and behaviour of machine parts to determine the changes in their properties and parameters from a single synergetic position. Development and implementation of integrated information systems for control of technological processes of manufacturing parts and machines assembly is an essential mover of the economic growth of industrialized countries. Complicating the operational conditions for the products increases the requirements for the parameters of their accuracy, surface layer quality, performance characteristics and reliability indicators. A mechanical engineering product is a technical system consisting of many subsystems and using the functionally-oriented design of technological processes planning for parts manufacturing. The structure and methodological providing of the PSPAS-system (Product Shaping / Processing Analysis System) investigates. PSPAS system includes the investigations of the technological inheritability of mechanical engineering product quality parameters combined with the analysis of traditional subsystems (cutting, surface plastic deformation, surface layer modification, assembly). Rheological simulation modelling, holding of experimental studies, the combination of mathematical modelling, theoretical and practical studies of technological processes ensure the implementation of the CAF system using the principle of functionally-oriented design during parts manufacturing and machines assembly.