bluuebunny/crossref_metadata_2025 huggingface dataset:
In vitro and in vivo validation of a new three‐dimensional fringe projection‐based device (AEVA‐HE) dedicated to skin surface mapping
Authors: Shaiek Ayet , Monot Muriel , Rubert Virginie , Cornillon Celine , Vicic Marco , Flament Frederic , Decocq Geraldine , Servant Jean‐Jacques , Koeller Gabriel , Lille Christelle
Published: February 2023

Background

Aging signs are much visible on the surface of the skin that presents different changes: cheeks start to sag, more and deeper wrinkles appear, and pigmentation spots increase. Face diagnostic to recommend products includes assessing cutaneous micro‐relief or the micro‐depressive network on the face. Furthermore, there is an increasing demand for clinical and instrumental methods to prove the efficacy of anti‐aging treatments. As a result, very accurate and sensitive three‐dimensional (3D) devices are developed and validated to measure and quantify aging skin and to catch fine anti‐aging products acting on wrinkles and fine lines.

Methods

AEVA‐HE, a non‐invasive 3D method based on fringe projection technology, is used to robustly characterize the skin micro‐relief from a full‐face acquisition and from multiple extracted zones of interest. In vitro and in vivo studies are conducted to assess the reproducibility of this system and its precision toward a standard fringe projection system, DermaTOP.

Results

The AEVA‐HE successfully measured micro‐relief and wrinkles and demonstrated the reproducibility of measurements.  AEVA‐HE parameters were found highly correlated to DermaTOP.

Conclusion

The present work illustrates the performance of the AEVA‐HE device and its dedicated software kit as a precious tool for quantifying the major characteristics of wrinkles appearing with age and thus offers a high potential for assessing the effect of anti‐wrinkling products.
DNA methylation remodeling in F1 hybrids
Authors: Kakoulidou Ioanna , Johannes Frank
Published: February 2023

F1 hybrids derived from a cross between two inbred parental lines often display widespread changes in DNA methylation patterns relative to their parents. To which extent these changes drive non‐additive gene expression levels and phenotypic heterosis in F1 individuals is not fully resolved. Current mechanistic models propose that DNA methylation remodeling in hybrids is the result of epigenetic interactions between parental alleles via small interfering RNA (sRNA). These models have strong empirical support but are limited to genomic regions where the two parental lines differ in DNA methylation status. However, most remodeling events occur in parental regions with similar methylation patterns, and seem to be strongly conditioned by distally acting factors, even in isogenic hybrid systems. The molecular basis of these distal interactions is currently unknown, and will likely emerge as an active area of research in the future. Despite these gaps in our molecular understanding, parental DNA methylation states are statistically associated with heterosis, independent of genetic information, and may serve as biomarkers in crop breeding.
Anatomy of the congenital calcaneal bursae in the bovine
Authors: Vermedal Hanna , Zingariello Edoardo , Hoey Seamus E. , De Pedro Anna J. , O'Leary John Mark
Published: February 2023

Objective

The objective of this study was to determine the anatomical relationship of the congenital calcaneal bursae in the bovine, and describe the computed tomography (CT), endoscopic and gross anatomy of these bursae.

Study design

Ex vivo experimental.

Sample population

Eighteen clinically normal cadaver bovine hindlimbs.

Methods

Intrasynovial injection of iodinated contrast and methylene blue into the intertendinous calcaneal bursa (ICB) (n = 16) or gastrocnemius calcaneal bursa (GCB) (n = 2). Limbs were imaged post‐contrast injection using multidetector CT. Endoscopic examination of the ICB was performed on two randomly selected limbs. All limbs underwent gross anatomical dissection.

Results

The anatomy of the congenital calcaneal bursae was consistent between CT imaging, endoscopic examination and gross dissection. The ICB and GCB were two separate synovial structures with no communication in all limbs. The distal and proximal extent of the ICB, defined as the distance from the point of tuber calcanei to the distal/proximal aspect of the ICB, was (median [IQR]) 7.4 (7.4 to 7.8) cm distally and 5.4 (4.7 to 6.0) cm proximally.

Conclusion

Positive contrast CT and gross anatomical dissection revealed no communication between the congenital calcaneal bursae in any limb. Routine bursoscopy allowed complete endoscopic examination of the ICB. The proximal extent of the ICB is shorter than the distal extent. The use of a collective term for these bursae should be avoided in the bovine, as the ICB and the GCB are two separate synovial structures with no communication.

Clinical significance

Knowledge of distinct anatomy and relationship between the congenital calcaneal bursae in the bovine may facilitate diagnosis and treatment of disorders affecting the region of tuber calcanei, including septic bursitis and osteomyelitis.
Validation and efficacy of ‘pure’ venous lymph node flap in a rat lymphoedema model
Authors: Cui Chunxiao , Nicoli Fabio , Min Peiru , Li Ke , Zhang Yixin
Published: February 2023

The venous lymph node flap (vLNF) is regarded as an arterialized or ‘pure’ venous flap, subject to which type of vessel provides blood supply to the flap. However, whether the vLNF drainage function is maintainable or sufficient for the treatment of lymphoedema is yet to be elucidated. In this study, the venous flow‐through lymph node flaps or ‘pure’ vLNF was investigated in a rat's tail (lymphoedema model), and the therapeutic effect was analysed to clarify its potential value for the treatment of lymphoedema. The subjects (rats) were divided into three groups, the experimental group (‘pure’ vLNF group), the control group (lymphoedema group), and the baseline group. The tail circumference and diameter were recorded for 5 weeks after the operation. Five weeks after surgery, the lymphatic drainage function was evaluated using indocyanine green (ICG) lymphography, while the skin thickness and collagen layer were assessed by histological analysis. The average diameter and circumference of the experimental group were significantly shorter than the control group (p < 0.01). When comparing ICG lymphography within the three groups, the baseline group showed that the ICG entered the inguinal lymph node and appeared in the liver while the ICG still accumulated in the oedematous tail with no fluorescence emerging in other parts of the rat's body, in the control group. In the experimental group, the ICG entered the vLNF via the flap junction with the rat's tail and fluorescence emerging in the rat's liver. When comparing the three groups above with the control group, the experimental group's skin and collagen layer thickness were significantly improved (p < 0.01). Lymphatic recanalization was shown to appear between ‘pure’ vLNF and the recipient area. Moreover, vLNF was shown to drain lymph fluid via the venous system, thus relieved swelling and fibrosis of the lymphoedematous tissue. Consequently, this could represent a new potential surgical approach for the treatment of lymphoedema.
Evidence‐based practice improves patient outcomes and healthcare system return on investment: Findings from a scoping review
Authors: Connor Linda , Dean Jennifer , McNett Molly , Tydings Donna M. , Shrout Amanda , Gorsuch Penelope F. , Hole Ashley , Moore Laura , Brown Roy , Melnyk Bernadette Mazurek , Gallagher‐Ford Lynn
Published: February 2023

Background

Evidence‐based practice and decision‐making have been consistently linked to improved quality of care, patient safety, and many positive clinical outcomes in isolated reports throughout the literature. However, a comprehensive summary and review of the extent and type of evidence‐based practices (EBPs) and their associated outcomes across clinical settings are lacking.

Aims

The purpose of this scoping review was to provide a thorough summary of published literature on the implementation of EBPs on patient outcomes in healthcare settings.

Methods

A comprehensive librarian‐assisted search was done with three databases, and two reviewers independently performed title/abstract and full‐text reviews within a systematic review software system. Extraction was performed by the eight review team members.

Results

Of 8537 articles included in the review, 636 (7.5%) met the inclusion criteria. Most articles (63.3%) were published in the United States, and 90% took place in the acute care setting. There was substantial heterogeneity in project definitions, designs, and outcomes. Various EBPs were implemented, with just over a third including some aspect of infection prevention, and most (91.2%) linked to reimbursement. Only 19% measured return on investment (ROI); 94% showed a positive ROI, and none showed a negative ROI. The two most reported outcomes were length of stay (15%), followed by mortality (12%).

Linking Evidence to Action

Findings indicate that EBPs improve patient outcomes and ROI for healthcare systems. Coordinated and consistent use of established nomenclature and methods to evaluate EBP and patient outcomes are needed to effectively increase the growth and impact of EBP across care settings. Leaders, clinicians, publishers, and educators all have a professional responsibility related to improving the current state of EBP. Several key actions are needed to mitigate confusion around EBP and to help clinicians understand the differences between quality improvement, implementation science, EBP, and research.
The Leopard, the Lion, and the Cock
Authors: Stanard Matthew
Published: February 2023

The degree to which the late colonial era affected Europe has been long underappreciated, and only recently have European countries started to acknowledge not having come to terms with decolonisation. In Belgium, the past two decades have witnessed a growing awareness of the controversial episodes in the country’s colonial past. This volume examines the long-term effects and legacies of the colonial era on Belgium after 1960, the year the Congo gained its independence, and calls into question memories of the colonial past by focusing on the meaning and place of colonial monuments in public space. The book foregrounds the enduring presence of “empire” in everyday Belgian life in the form of permanent colonial markers in bronze and stone, lieux de mémoire of the country’s history of overseas expansion. By means of photographs and explanations of major pro-colonial memorials, as well as several obscure ones, the book reveals the surprising degree to which Belgium became infused with a colonialist spirit during the colonial era. Another key component of the analysis is an account of the varied ways in which both Dutch- and French-speaking Belgians approached the colonial past after 1960, treating memorials variously as objects of veneration, with indifference, or as symbols to be attacked or torn down. The book provides a thought-provoking reflection on culture, colonialism, and the remainders of empire in Belgium after 1960.
The post‐arteriole transitional zone: a specialized capillary region that regulates blood flow within the CNS microvasculature
Authors: Mughal Amreen , Nelson Mark T. , Hill‐Eubanks David
Published: February 2023

The brain is an energy hog, consuming available energy supplies at a rate out of all proportion to its relatively small size. This outsized demand, largely reflecting the unique computational activity of the brain, is met by an ensemble of neurovascular coupling mechanisms that link neuronal activity with local increases in blood delivery. This just‐in‐time replenishment strategy, made necessary by the limited energy‐storage capacity of neurons, complicates the nutrient‐delivery task of the cerebral vasculature, layering on a temporo‐spatial requirement that invites ‐ and challenges ‐ mechanistic interpretation. The centre of gravity of research efforts to disentangle these mechanisms has shifted from an initial emphasis on astrocyte‐arteriole‐level processes to mechanisms that operate on the capillary level, a shift that has brought into sharp focus questions regarding the fine control of blood distribution to active neurons. As these investigations have drilled down into finer reaches of the microvasculature, they have revealed an arteriole‐proximate subregion of CNS capillary networks that serves a regulatory function in directing blood flow into and within downstream capillaries. They have also illuminated differences in researchers’ perspectives on the vascular structures and identity of mural cells in this region that impart the vasomodulatory effects that control blood distribution. In this review, we highlight the regulatory role of a variably named region of the microvasculature, referred to here as the post‐arteriole transition zone, in channeling blood flow within CNS capillary networks, and underscore the contribution of dynamically contractile perivascular mural cell – generally, but not universally, recognized as pericytes – to this function.

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Intestinal distension orchestrates neuronal activity in the enteric nervous system of adult mice
Authors: Cavin Jean‐Baptiste , Wongkrasant Preedajit , Glover Joel B. , Balemba Onesmo B. , MacNaughton Wallace K. , Sharkey Keith A.
Published: February 2023

The enteric nervous system (ENS) regulates the motor, secretory and defensive functions of the gastrointestinal tract. Enteric neurons integrate mechanical and chemical inputs from the gut lumen to generate complex motor outputs. How intact enteric neural circuits respond to changes in the gut lumen is not well understood. We recorded intracellular calcium in live‐cell confocal recordings in neurons from intact segments of mouse intestine in order to investigate neuronal response to luminal mechanical and chemical stimuli. Wnt1‐, ChAT‐ and Calb1‐GCaMP6 mice were used to record neurons from the jejunum and colon. We measured neuronal calcium response to KCl (75 mM), veratridine (10 μM), 1,1‐dimethyl‐4‐phenylpiperazinium (DMPP; 100 μM) or luminal nutrients (Ensure®), in the presence or absence of intraluminal distension. In the jejunum and colon, distension generated by the presence of luminal content (chyme and faecal pellets, respectively) renders the underlying enteric circuit unresponsive to depolarizing stimuli. In the distal colon, high levels of distension inhibit neuronal response to KCl, while intermediate levels of distension reorganize Ca2+ response in circumferentially propagating slow waves. Mechanosensitive channel inhibition suppresses distension‐induced Ca2+ elevations, and calcium‐activated potassium channel inhibition restores neuronal response to KCl, but not DMPP in the distended colon. In the jejunum, distension prevents a previously unknown tetrodotoxin‐resistant neuronal response to luminal nutrient stimulation. Our results demonstrate that intestinal distension regulates the excitability of ENS circuits via mechanosensitive channels. Physiological levels of distension locally silence or synchronize neurons, dynamically regulating the excitability of enteric neural circuits based on the content of the intestinal lumen.

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Key points

How the enteric nervous system of the gastrointestinal tract responds to luminal distension remains to be fully elucidated.

Here it is shown that intestinal distension modifies intracellular calcium levels in the underlying enteric neuronal network, locally and reversibly silencing neurons in the distended regions.

In the distal colon, luminal distension is integrated by specific mechanosensitive channels and coordinates the dynamics of neuronal activation within the enteric network.

In the jejunum, distension suppresses the neuronal calcium responses induced by luminal nutrients.

Physiological levels of distension dynamically regulate the excitability of enteric neuronal circuits.
Role of Secondary Ions on the i-v Characteristics of Oxyfuel Flame Subject to an Electric Field
Authors: Untaroiu Alexandrina , Rahman S. M. Mahbobur , Martin Christopher R.
Published: February 2023

Recent use of ion currents as a sensing strategy in the mechanized oxyfuel cutting process motivated a series of studies which revealed that the steel work piece contributes secondary ions in addition to the primary ions classically identified in the oxyfuel flame. In this work, we present a computational model that has linked carbon-related chemi-ions as a source of secondary ions in preheating stage of oxyfuel cutting process subject to electric bias voltages. The flames' response to the electric field at different positive and negative polarities manifested a better understanding of the physical behavior of current-voltage (i-v) relationship. While copper surface exhibits stable and repeatable i-v characteristics, sporadically enhanced current was observed in positive saturation regime for steel surface, and this is believed to be due to the presence of secondary chemi-ions. To this extent, a source term of gaseous carbon has been assigned to mimic the ‘work surface’ reactions. The hypothesis is that since carbon is an important element, it will be diffusing out of the steel surface and evaporate into the flame.
Design and Development of a Spherical 5-Bar Thumb Exoskeleton Mechanism for Poststroke Rehabilitation
Authors: Ketkar Vishwanath D. , Wolbrecht Eric T. , Perry Joel C. , Farrens Andria
Published: February 2023

This paper presents the kinematic design and development of a two degree-of-freedom (2DOF) spherical 5-bar thumb exoskeleton to augment the finger individuating grasp exercise robot (FINGER) rehabilitation robot, which assists the index and middle fingers individually in naturalistic grasping. The thumb module expands the capabilities of FINGER, allowing for broader proprioceptive training and assessment of hand function. The design process started by digitizing thumb-grasping motions to the index and the middle fingers separately, recorded from multiple healthy subjects utilizing a motion capture system. Fitting spheres to trajectory data of each subject allowed normalization of all subjects' data to a common center and radius. A two-revolute joint serial-chain mechanism was synthesized (intermediate optimization step) to reach the normalized trajectories. Next, the two resulting grasping trajectories were spatially sampled as targets for the 2DOF spherical 5-bar synthesis. Optimization of the spherical 5-bar included symmetry constraints and cost-function penalties for poor manipulability. The resulting exoskeleton assists both flexion/extension and abduction/adduction of the thumb enabling a wide range of motions. Consistent with FINGER, the parallel structure of the spherical 5-bar places the actuators at the base of the module, allowing for desirable characteristics, including high backdrivability, high controllable bandwidth, and low mechanical impedance. The mechanical design was developed from the kinematic solution, including an adjustable thumb cuff to accommodate different hand sizes. Fit and function of the device were tested on multiple subjects, including survivors of stroke. A proportional-derivative force controller with gravity and friction compensation was implemented to reduce resistance to motion during subject testing.
A Curved Compliant Differential Mechanism With Neutral Stability
Authors: Mak Robin , Amoozandeh Nobaveh Ali , Radaelli Giuseppe , Herder Just L.
Published: February 2023

Differential mechanisms are remarkable mechanical elements that are widely utilized in various systems; nevertheless, conventional differential mechanisms are heavy and difficult to use in applications with limited design space. This paper presents a curved differential mechanism that utilizes a lightweight, compliant structure. This mechanism acquires its differential characteristic by having a high rotational stiffness when the mechanism is symmetrically actuated on two sides, while having a low rotational stiffness when actuated only on one side. To make the mechanism neutrally stable, the intrinsic elastic strain energy required for deformation of the compliant differential is compensated for by the reintroduction of potential energy, which is provided by two preloaded springs. The rotational stiffness of the one-sided actuation of the compliant differential mechanism around the neutral position is hypothesized to be adjustable by changing the preload of the springs. The stiffness can be positive, zero, or negative, indicating that the mechanism can be neutral or bistable. This hypothesis is investigated using a simulated model in Ansys Parametric Design Language (APDL) using optimized parameters to achieve the desired stiffness for the mechanism. The simulated model is validated using an experimental setup for both the one-sided and symmetrical actuation stages. The experimental results showed a high correlation with the simulation results. The mechanism with optimized dimensions and preload demonstrated neutral stability over a 16deg range. Bistability was discovered for preloads greater than the optimized preload. At θ = 0, a linear relationship was discovered between the spring preload and the rotational stiffness of the mechanism. Furthermore, an output/input kinematic performance of 0.97 was found for the simulated results and 0.95 for the experimental results.
A Rational Approach to Meshing Cerebral Venous Geometries for High-Fidelity Computational Fluid Dynamics
Authors: Haley Anna L. , Sidora Gurnish , Cancelliere Nicole M. , Pereira Vitor M. , Steinman David A.
Published: February 2023

Computational fluid dynamics (CFD) of cerebral venous flows has become popular owing to the possibility of using local hemodynamics and hemoacoustics to help diagnose and plan treatments for venous diseases of the brain. Lumen geometries in low-pressure cerebral veins are different from those in cerebral arteries, often exhibiting fenestrations and flattened or triangular cross section, in addition to constrictions and expansions. These can challenge conventional size-based volume meshing strategies, and the ability to resolve nonlaminar flows. Here we present a novel strategy leveraging estimation of length scales that could be present if flow were to become transitional or turbulent. Starting from the lumen geometry and flow rate boundary conditions, centerlines are used to determine local hydraulic diameters and cross-sectional mean velocities, from which flow length scales are approximated using conventional definitions of local Kolmogorov and Taylor microscales. By inspection of these scales, a user specifies minimum and maximum mesh edge lengths, which are then distributed along the model in proportion to the approximated local Taylor length scales. We demonstrate in three representative cases that this strategy avoids some of the pitfalls of conventional size-based strategies. An exemplary CFD mesh-refinement study shows convergence of high-frequency flow instabilities even starting from relatively coarse edge lengths near the lower bounds of the approximated Taylor length scales. Rational consideration of the length scales in a possibly nonlaminar flow may thus provide a useful and replicable baseline for denovo meshing of complicated or unfamiliar venous lumen geometries.
Design and Analysis of Multifidelity Finite Element Simulations
Authors: Shaowu Yuchi Henry , Roshan Joseph V. , Jeff Wu C. F.
Published: February 2023

The numerical accuracy of finite element analysis (FEA) depends on the number of finite elements used in the discretization of the space, which can be varied using the mesh size. The larger the number of elements, the more accurate the results are. However, the computational cost increases with the number of elements. In current practice, the experimenter chooses a mesh size that is expected to produce a reasonably accurate result, and for which the computer simulation can be completed in a reasonable amount of time. Improvements to this approach have been proposed using multifidelity modeling by choosing two or three mesh sizes. However, mesh size is a continuous parameter, and therefore, multifidelity simulations can be performed easily by choosing a different value for the mesh size for each of the simulations. In this article, we develop a method to optimally find the mesh sizes for each simulation and satisfy the same time constraints as a single or a double mesh size experiment. A range of different mesh sizes used in the proposed method allows one to fit multifidelity models more reliably and predict the outcome when meshes approach infinitesimally small, which is impossible to achieve in actual simulations. We illustrate our approach using an analytical function and a cantilever beam finite element analysis experiment.
New Design for Implementation of 2-Degree-of-Freedom Planar Parallel Robot for Use in Creating an Infinite 3D Printer
Authors: De La Melena Miguel , Duan Shawn
Published: February 2023

3D printing is a rapidly growing and evolving field filled with a diverse array of printers capable of printing an equally as diverse amount of material. A new type of material extrusion 3D printer was recently developed and features the capabilities of printing infinitely long objects due to design decision of angling the XY plane and incorporating a rotating bed. The innovative design for the infinite 3D printer features a 2-DoF planar parallel manipulator (PPM) that will control the hot-end motion in the XY plane. This innovative design will greatly reduce the mass of moving parts in comparison to other infinite 3D printers. This reduction of weight will reduce inertia and allow for this new printer to achieve higher accelerations. In addition to the development of the new 3D printer, this paper presents a kinematic and dynamic model of the angled PPM, a finite element analysis of the critical components of the PPM, and an optimization approach to determine arm length of the PPM. The dynamic model simulation was developed in MATLAB and the results were compared with field data collected to verify the model. A meta-heuristic optimization was performed to optimize arm length of the connectors while maximizing the dynamic performance of the PPM with consideration of the usable workspace. The results of these examinations yield a validated mechanism that will be suitable for the development of a new type of infinite 3D printer.
How Do Maintenance Personnel Perceive Occupational Safety and Health (OSH) Risks During Major Overhauls, Outages, Shutdowns or Turnarounds (MoOSTs)? An Examination of the Nigerian Cement Industry
Authors: Yunusa-Kaltungo Akilu , Jungudo Rukaiyatu Mohammed , Ray Srija , Sokunbi Idowu
Published: February 2023

Asset management activities such as periodic overhauls are crucial for ensuring asset integrity and workplace safety. However, lessons learned from previous major industrial accidents across various high-risks industries have indicated that the perception of occupational safety and health (OSH) risks of maintenance personnel during major overhauls, outages, shutdowns and turnarounds (MoOSTs) are common denominators and precursors to several accidents. This is typically owing to several factors especially the fusion of all classes of routine maintenance tasks on enormous scales and the integration of a very diverse workforce (client, regulators, original equipment manufacturers, and various contracting firms) that possess very different safety cultures, which in turn compound overall risk profiles of job sites and the likelihood of accidents. Therefore, developing a good understanding of the risks perceptions and attitudes of MoOSTs workers towards can help improve overall OSH performance. Although several studies have investigated the subject of safety culture and climate in the context of projects especially engineering, procurement and construction (EPCs), however, studies and use cases on MoOSTs are significantly underrepresented, despite their impacts on costs, employment and wellbeing. This study therefore aims to advocate a safety culture that would boost OSH performance during MoOSTs through the development and deployment of safety climate questionnaire survey to MoOSTs workers of leading cement manufacturing operations in Nigeria. The study revealed “training and learning from incidents”, “commitment of senior management towards ensuring safety and its protocol deployment process”, and “effectiveness of incident reporting systems during MoOSTs” as the three main underlying safety climate factors.
CFD Study of the Influence of SARS-CoV-2 Deposition on Human Lung Dynamic: A Comparison Between Healthy and Diseased Condition
Authors: Carotenuto Carlo , Scurani Letizia , Fontanili Luca , Montorsi Luca , Milani Massimo
Published: February 2023

This paper presents a numerical approach to analyze the influence of SARS-CoV-2 deposition on human lung dynamics under real conditions. A comparison is made between a healthy and a diseased lung. A multiphase three-dimensional computational fluid dynamics (CFD) study is performed for the dispersion of covid-19 virus particles throughout the alveolar tree. Then, fully coupled fluid-structure interaction (FSI) is used to evaluate the expansion properties of the alveolar wall. The mesh morphing technique with solid displacement characteristics is used to obtain a realistic wall displacement during the inspiratory and expiratory phases corresponding to the expansion and retraction of the alveolar sac, respectively. These phases are studied under steady-state conditions. The main objective of this study is to evaluate how particle deposition alters the displacement of alveoli exposed to a Sars-Cov-2 and to compare the obtained simulation results with the healthy case. The novelty of this analysis is that it examines where the virus is most deposited and how the presence of Sars-Cov-2 can affect the mechanical properties of the alveolar sac and worsen the respiratory capacity of a sick person at an advanced stage of infection.
Spontaneous Enlargement of Receptor Clusters in Response to Pulling Traction
Authors: Sarvestani Alireza S. , Moorthy Arsha
Published: February 2023

Most adherent cells are capable of sensing the external forces and probing the mechanical properties of their surroundings. These are classical hallmarks of what is termed mechanotransduction. Mechanotransduction is generally attributed to the sensory functions of focal adhesion (FA) proteins upon activation by mechanical stimuli. A striking feature of cell mechanosensing is the growth of FAs in response to increased cytoskeletal or extracellular tension. Despite growing knowledge about the molecular structures of cell focal adhesions, it has remained elusive as to how these anchorage points grow and how their sensory function operates. The aim of this contribution is to show that force-dependent enlargement of FAs could be driven by spontaneous clustering of transmembrane receptors, independent from active sensory mechanisms. The elasticity of bonds is the key regulator of this process. The mechanical work associated with the cytoskeletal tension alters the free energy landscape and facilitates the recruitment of free receptors to establish new bonds with ligands. Therefore, mechanotransduction could be the manifestation of a thermodynamic process in cell FAs to achieve the state of minimum free energy, independent from the sensory function of molecular sensors in FAs, as postulated in available models.
A Model-Based Approach for Integrated Variation Management
Authors: Horber Dennis , Götz Stefan , Schleich Benjamin , Wartzack Sandro
Published: February 2023

Variation management is a responsible task for product developers, which have to balance the ever-increasing quality demands and cost pressures, while considering the product design as well as the manufacturing and assembly process. These aspects have a direct impact on its subsequent success in the market. Therefore, a large number of different activities of variation management are necessary. In this area, a wide variety of mostly document-centered methods support product developers, which have individual interfaces. Thus, it is currently not possible to map the entire variation management process in a single model. Especially with regard to the increasing availability of large amounts of data, the potential of an integrated variation management cannot be exploited efficiently. For this reason, this paper presents a novel model-based approach for the development of a combined system and tolerancing model. This model contains the processes and activities of integrated variation management and links them with further system models and the corresponding data. The presented approach is a superordinate model for variation management as well as its processes and provides the modeling of individual views of different stakeholders. In addition, process- and program-specific solutions can be integrated into the model, which enables a cross-linking of the data beyond their interfaces. In this paper, the approach is realized using the systems modeling language (SysML).
Modelling of Surface Roughness in CO2 Laser Ablation of Aluminium-Coated Polymethyl Methacrylate (PMMA) Using Adaptive Neuro-Fuzzy Inference System (ANFIS)
Authors: Okello Job Lazarus , El-Bab Ahmed M. R. Fath , Yoshino Masahiko , El-Hofy Hassan A. , Hassan Mohsen A.
Published: February 2023

High surface roughness hinders the flow of fluids in microchannels leading to low accuracy and poor-quality products. In this work, the adaptive neuro-fuzzy inference system (ANFIS) was used to examine surface roughness in CO2 laser fabrication of microchannels on polymethyl methacrylate (PMMA). The PMMA substrates were coated with a 500 nm layer of 99.95% pure aluminium. The inputs were speed (10, 15, and 20 mm/s), power (1.5, 3.0, and 4.5 W), and pulse rate (800, 900, and 1000 pules per inch) while the output was surface roughness. A 3-level full factorial design of experiments was used, and 27 experiments were conducted. Using the gaussian membership function (gaussmf), the ANFIS model was developed using the ANFIS toolbox in MATLAB R2022a. Analysis of variance was performed to examine the significance of the inputs. Power is the most significant followed by speed and pulse rate. The mean relative error (MRE), mean absolute error (MAE), and the correlation coefficient (R) were used to examine the accuracy and viability of the model. MRE, MAE, and R were found to be 0.257, 0.899, and 0.9957 (R2 = 0.9914) respectively. The root mean square error (RMSE) was 0.0022 and 3.6099 for the training data and checking data respectively. Hence, the developed model can predict the values of the average surface roughness with high accuracy.
Predicting Motion of Engine-Ingested Particles Using Deep Neural Networks
Authors: Bowman Travis , Miranda Cairen , Palmore John
Published: February 2023

The ultimate goal of this work is to facilitate the design of gas turbine engine particle separators by reducing the computational expense to accurately simulate the fluid flow and particle motion inside the separator. It has been well-documented that particle ingestion yields many detrimental impacts for gas turbine engines. This ingestion is of concern for operation in environments where dust, ash, or ice persist. The consequences of ice particle ingestion can range from surface-wear abrasion to engine power loss. Ice particles are chosen for this study because of their relevance to civil aviation. It is known that sufficiently small particles, characterized by small particle response times (τp), closely follow the fluid trajectory whereas large particles deviate from the streamlines. The behavior of small particles hints at a method for larger particle trajectories because the higher order terms (HOT) in the asymptotic particle acceleration solution can be shown to be O(τp). By explicitly considering τp, these HOT can be derived. Rather than manually deriving these terms, this work chooses to implicitly derive them using machine learning (ML). Inertial particle separators are devices designed to remove particles from the engine intake flow. Particle separators contribute to both elongating the lifespan and promoting safer operation of aviation gas turbine engines. Complex flows, such as flow through a particle separator, naturally have rotation and strain present throughout the flow field. This study attempts to understand if the motion of particles within rotational and strained canonical flows can be accurately predicted using supervised ML. This report suggests that preprocessing the ML training data to the fluid streamline coordinates can improve model training. Furthermore, this work provides some guidelines for applying ML, particularly deep feed-forward neural networks, with physics driven multiphase flow data. Additionally, the ML model is able to predict the particle accelerations in the fully rotational and irrotational canonical laminar flows quite well. For combined flows with rotation and strain, however, the model struggles to predict the particle accelerations.
Topology Optimization for Acoustic Structures Without Floating Components
Authors: Noguchi Yuki , Ohta Yusei , Matsushima Kei , Yamada Takayuki
Published: February 2023

We propose a level-set method for topology optimization to design acoustic structures without unsupported floating structures. The proposed method involves developing an artificial physical model for detecting floating structures and an objective function for eliminating them. As a design problem, we chose acoustic cloaking and formulated a topology optimization problem under geometric constraints. We applied an optimization algorithm that includes finite element analysis for the acoustic system and an artificial physical field. We provide several numerical examples demonstrating the validity and applicability of the proposed method, and we show how it can be used to design a cloaking structure without any floating components.
High Resolution Real Time Synthetic Aperture Imaging in Solids Using Virtual Elements
Authors: Huang Chengyang , Lanza di Scalea Francesco
Published: February 2023

This paper discusses some improvements to ultrasonic synthetic aperture imaging in solids with primary applications to in-situ non-destructive testing of railroad tracks. Specifically, the study examines three different subarray emission modalities that enhance the signal-to-noise ratio in ultrasound inspection using a phased array with the addition of a transducer wedge. The subarray emission approach effectively compensates for the loss of synthetic transmit power in sparse transmission. Numerical analysis and experimental testing of a point scatterer evaluate the focusing ability of the three subarray emission methods with different subaperture configurations. The Delay-and-Sum (DAS) algorithm builds synthetic aperture images by tracing the refracted ray paths in the multi-layered structure. The transmit subarrays are modeled as virtual elements in the DAS algorithm to accommodate the phase coherence of the synthetic wavefronts. The best subaperture configuration is found by evaluating the resolution and contrast of synthetic aperture images of a subwavelength scatterer in an aluminum block. The SAF imaging approach proposed in this paper have been tested in a portable system aimed at the imaging of internal flaws in rails. The ability to obtain 3D images of rail flaws is badly needed in the railroad maintenance community to enable the most informed remedial decisions following the detection of a defect. The portable system utilizes GPU parallel computation to realize quasi real-time DAS beamforming, and defects are visualized in 3D with calibration of the rail profile. Results are shown from a series of tests conducted on a variety of flaws present in rail sections. These results show the improvements in both imaging speed and signal strength that can be achieved by the subarray emission methods over the conventional synthetic aperture imaging methods.
Development of a Control Co-Design Modeling Tool for Marine Hydrokinetic Turbines
Authors: Ross Hannah , Hall Matthew , Herber Daniel R. , Jonkman Jason , Sundarrajan Athul Krishna , Tran Thanh Toan , Wright Alan , Zalkind Daniel , Johnson Nick
Published: February 2023

This report describes the ongoing and planned development of the software package CT-Opt (Current/Tidal Optimization), a control co-design modeling tool for marine hydrokinetic turbines. The commercialization of these turbines has faced significant challenges due to the complex, multidisciplinary nature of their design and the extreme environmental conditions of their operation. This project aims to create a modeling tool that will enable the efficient design of robust, cost-competitive hydrokinetic turbine systems. Rather than using traditional optimization methods, CT-Opt combines multiple models across a range of fidelities to enable coupled optimization of the system design and system controller via a control co-design approach. With this method, the parameters that affect system performance are considered more comprehensively at every stage of the design process. The lowest-fidelity, frequency-domain model called by CT-Opt is RAFT (Response Amplitudes of Floating Turbines), which was originally developed by the National Renewable Energy Laboratory (NREL) to model response amplitudes of floating offshore wind turbines. The highest-fidelity, time-domain model is OpenFAST, which was developed by NREL for land-based and offshore wind turbines. As part of the CT-Opt project, new functionalities will be added to RAFT and OpenFAST to enable the accurate simulation of fixed and floating marine hydrokinetic turbines. In addition to expanding the capabilities of RAFT and OpenFAST, new mid-fidelity models will be developed. These models will be based on RAFT and OpenFAST and will consist of linearized, state-space models derived from the fully coupled, nonlinear OpenFAST equations and derivative function surrogate models that approximate the nonlinear system behavior. Each model will be coupled with controllers to allow control co-design methods to be applied both within models and across fidelity levels, enabling efficient system optimization.
An Artificial Neural Network Model for Multiple Piezoelectric Actuation of Plates
Authors: Jiang Linjin , Yu Pengcheng , Fan Mu
Published: February 2023

With the increasing use of piezoelectric smart structures in various fields, the search for further optimization of the devices is inevitable. In this work, both artificial neural network (ANN) models and finite element models were used to explore the effect of piezoelectric patch size and numbers on the first order natural frequency and transverse displacement of a plate. The research objective is to investigate the efficiency and factors influencing the actuation of thin plate structures under single/multi-channel piezoelectric control conditions. A Finite element model built with COMSOL was used to analyze the effect of structural parameters, including the number of channels and other key parameters on the control of the main natural frequencies of the thin plate structure. With the obtained data from finite element simulations, an ANN model was used to predict the dynamic response of the plate, including the first-order natural frequency and displacement amplitude for finite element verification, so that structural optimization design can be achieved. A well-trained neural network model can quickly and efficiently predict the displacement amplitude and natural frequency of a piezoelectric driven rectangular plate. This study provides a convenient and effective method for predicting the dynamic response of a piezoelectric drive plate considering the number of piezoelectric patch channels and size effects.
Numerical Simulation of Aged Reinforced Concrete Column Nonlinear Creep due to High Sustained Load
Authors: Ma Wenchen
Published: February 2023

A numerical simulation method for predicting reinforced concrete (RC) column creep under high axial sustained stresses exceeding 75% of concrete short-time strength f’c with loading ages greater than 200 days is explored. The objective is to investigate a comprehensive approach to predicting reinforced columns’ long-term nonlinear behavior. Nonlinear creep of RC columns is modeled based on combining a theoretical framework for the time-dependent uniaxial behavior of plain concrete under high axial sustained loads and an age-adjusted effective modulus method for calculating linear creep of reinforced concrete columns. The mechanism of the theoretical framework is improved by extending the prediction of linear concrete creep estimated by the GL2000 model to that of nonlinear concrete creep. The measured experimental results of concentrically loaded column tests are compared with the predictions from the numerical simulation method. For the RC columns loaded to 76% of their short-time strength calculated by the ACI equations without considering any strength reduction factor, the difference between the measured and predicted creeps at the end of sustained loading was less than 6%. However, for the RC columns loaded with 98% of column shoer-time strength, the predicted creep was 26% and 18% greater than the measured creep at the end of sustained loading. The research is concluded that the reason caused the predicted creep is greater than the measured creep because transverse reinforcement can restrain concrete creep under higher sustained stresses, especially in the early stage of sustained loading.
Investigation of Undeformed Chip Thickness Model and Surface Roughness Prediction in Belt Grinding
Authors: Li Heng , Zou Lai , Wang Wenxi , Li Mingcong
Published: February 2023

Undeformed chip thickness plays a very important role in studying the materials remove mechanism in flexible belt grinding and predicting ground surface roughness. A calculation model that can be used to effectively predict the undeformed chip thickness in flexible belt grinding is established based on the height distribution of abrasive grains. It can lay the foundation for in-depth study of belt grinding mechanism. In this model, the real contact arc length is derived based on the elastic deformation of the contact area between the abrasive belt and workpiece. The real depth of cut prediction model is introduced considering the belt grinding processing characteristics. Based on the established undeformed chip thickness model, a ground surface roughness calculation model is further reached, and a series of verification experiments are carried out. The results show that the predicted value and the measured value have the same trend basically under different grinding process parameters. The error of the predicted value is mostly distributed between 5% and 16%, which proved the reliability of the developed models preliminary.