bluuebunny/crossref_metadata_2025 huggingface dataset:
Green way of improving the thermal efficiency of mortars by the addition of biobased phase change materials
Authors: Rubio-Aguinaga Andrea , Fernández José María , Navarro-Blasco Íñigo , Álvarez José Ignacio
Published: September 2024

The thermal efficiency of air lime-based mortars was improved by directly integrating varying amounts (5 wt. %, 10 wt. %, and 20 wt. %) of a microencapsulated biobased phase change material (PCM) into the fresh mortars. This PCM is made of vegetable oils and other organic wastes from the agri-food sector. The mortar formulation was optimized by adding different chemical additives and mineral admixtures. The mortar formulation was meticulously designed to produce rendering mortars that are easily workable, crack-free, and fully adherent for use in building envelopes. Positive outcomes in thermal efficiency tests have demonstrated the ability of these materials to store thermal latent energy, offering an environmentally friendly alternative to enhance the thermal comfort of building inhabitants.
Natural additives as reinforcement for mortars: Comparative evaluation of gypsum-based plasters with pistachio shells and orange peels
Authors: Fernandez Federica , Insinga Maria Grazia , Basile Roberta , Zagarella Federica , Germanà Maria Luisa
Published: September 2024

This research explores the use of waste from agriculture and food production (agro-food waste) as a green additive in building gypsum plasters. The focus is on lightweight mortars made with bio-based materials, aiming for a solution that aligns with green building principles and circular economy practices. Current research prioritizes examining the physical and mechanical properties of these bio-based mortars. These mortars often have high porosity and lower weight, making them good thermal insulators and sound absorbers. While not yet widely used in construction, they hold promise as a sustainable alternative with performance comparable or even exceeding conventional plasters in thermal and acoustic insulation. In particular, the cultural premises of this study refer to the shared identity between Sicily and Tunisia, focused by a recent strategic cross-border cooperation project CUBÂTI, Culture du bâti de qualité: recherche, innovation et entreprise pour la durabilité, funded by Italy-Tunisie Programme 2014-2020. In fact, the present experimental research has focused on two materials easy to find in these countries, applying a replicable method to other regions in the Mediterranean area. In this study, the performances of gypsum-based plasters with pistachio shells and orange peels as additives were evaluated. Several tests were carried out on the developed materials to optimize their mix design, verify their mechanical and physical properties and the results of the comparative investigations showed interesting results in terms of mechanical resistance, thermal conductivity and reduction of water absorption.
Comparative study of moisture absorption and resistance to NaCl salt of clay-based plasters incorporating porous aggregate
Authors: Kushnierova Liliia , Ghiassi Bahman , Khine Myat
Published: September 2024

This study deals with the effects of expanded perlite and two types of clay (bentonite and kaolin) on adsorption behaviour of lightweight clay-cement based plasters and their resistance to the destructive impact of NaCl salt solution. In these plaster mixers cement is replaced by a 50% (vol.) kaolinite clay and bentonite content, as sand is replaced by a 100% (vol.) expanded perlite content. In this study such properties were examined as open porosity, bulk density, saturation moisture content, capillary absorption coefficient and salt resistance. The results indicate that the incorporation of both clay and perlite allows for the production of plasters with a bulk weight and porosity reduction of 100% and 400% respectively. The ability to absorb salt solution increases with incorporating of expanded perlite. Bentonite incorporating plasters show the lowest salt resistance in comparison with kaolinite clay.
Investigation of the bed joint reinforcement effect on the drift capacity of modern unreinforced masonry walls
Authors: Inzunza Ernesto , Saloustros Savvas , Beyer Katrin
Published: September 2024

Bed joint reinforcement significantly affects the shear capacity of masonry walls due to its effective ability to transfer shear forces through a diagonal crack, but how does this phenomenon impact its drift capacity? This paper presents an experimental study containing a series of four quasi-static cyclic tests conducted on masonry walls of same size. Two of them incorporated truss-type bed joint reinforcement, while the other two were completely unreinforced. All specimens were subjected to double bending boundary conditions to observe shear-controlled behaviour and were tested under two levels of compression load. The primary objective of this research is to determine the role of horizontal reinforcement in the seismic properties of unreinforced masonry walls focusing on the displacement capacity. The findings from this experimental study are expected to provide empirical evidence for subsequent numerical simulations and contribute to the development of analytical formulations. The results aim to enhance our understanding of the seismic response of masonry walls, ultimately informing design practices and seismic retrofitting strategies.
Thermal properties of new ceramic biomaterial for building façades
Authors: Spahiu Kaltrina , Samardzioska Todorka , Gramatikov Kiril , Nushi Violeta
Published: September 2024

The selection of materials for a building facade is based on the dimensions of sustainability: environmental, economic and social dimensions, which form the basis of design and construction in terms of environmental conservation and energy efficiency. Furthermore, this implies the formula for maintaining balance: comfort in the indoor environment, care for nature, minimal economic expenses. This paper focuses on the investigation of a new material composed of bio and recyclable materials: clay, sawdust, and slag, i.e. materials found in abundance in nature as well as materials left out of use. The selected materials offer significant potential for use in construction industry, for building façades. Laboratory testing of the thermal properties of the new material, particularly of the thermal conductivity λ (W/m·K) that is crucial for thermal comfort in buildings to promote energy efficiency, has been performed. Three sets of samples (9 samples in total) with different proportions of the constitutive materials were tested using the Heat Flow Meter (HFM) instrument. Based on the results obtained, several conclusions have been drawn to demonstrate the potential for interaction among used materials, offering advancements in terms of thermal properties. Namely, thermal conductivity of the tested samples varies between 0.14 W/m·K and 0.18 W/m·K, depending on the density of the samples. This value is 7-9 times lower than the thermal conductivity value of traditional clay full bricks without voids and cavities and indicates new possibilities for energy efficient facades, promising environmental preservation, harmonization with nature, offering the solution with the slag and sawdust deposition.
Masonry walls from reclaimed concrete demolition waste
Authors: Oreb Jakov , Curić Haris , Tomić Igor , Beyer Katrin
Published: September 2024

The construction sector is the largest consumer of non-renewable resources and the most significant contributor to CO2 emissions. Reusing entire components or reclaiming their constituent parts, instead of recycling structural elements at the material level, is preserving the embodied energy of the structural elements. This contributes to energy conservation and addresses the mounting issue of construction waste in landfills. In order to develop a new avenue for reusing concrete, this study uses concrete demolition waste to construct masonry wallets, employing a construction technique reminiscent of traditional stone masonry with mortar. Importantly, this methodology is not confined to buildings initially designed for reuse, making it applicable to any reinforced concrete structure earmarked for demolition. Mechanical tests were conducted on the masonry wallets, including simple and diagonal compression tests. The results indicate that the strengths achieved are comparable to those of clay hollow brick masonry, opening up diverse applications, especially in the construction of residential buildings. Numerical analysis started with digital twinning of small-scale masonry wallets as a first step to future micro-modelling, FEM simulation, and calibration to best conform with the experimental test results. Through a comprehensive analysis encompassing embodied carbon footprint, mechanical properties, and economic considerations at the load-bearing wall level, this study highlights this reuse approach’s key advantages and drawbacks, providing insights into its feasibility within the framework of modern construction practices.
Bricks, Mud and Lime Mortars in Heritage Restoration: A case study
Authors: Amatya Pooja , Ranjitkar Rohit , Man Pradhan Prachand , Rijal Lochan
Published: September 2024

This paper is based upon an extensive eight-year experience in the restoration of monuments from the World Heritage Site Patan Darbar Square to Tripureshwor Mahadev Temple, Sattals, and Garden Area and the Sama Center, representing historically significant Malla, Shah and Rana period architectures respectively, after the Gorkha earthquake of 2015. These monuments date back from 6th to the 20th century. All structures employ a masonry system as the structural system. The main materials observed in these heritages were burnt clay bricks, stones, mud mortars, and lime mortars. This study examines the technical aspects such as material properties (compressive strength, bending strength, mechanical properties), and composition of mortars according to their use in different locations and types of structures, even within the same building. The study acknowledges the Department of Archaeology’s preservation and monument act, highlighting the potential for material reuse in heritage restoration. The primary aim of this study is to comprehensively understand and analyze the strength of antiquated materials and traditional mortars used in historical construction and restoration. It provides practical recommendations for future preservation efforts.
Cape Verde Air Lime: Production and application
Authors: Marques Vera , Velosa Ana
Published: September 2024

Air lime has been a major element in both vernacular and urban construction in Cape Verde, from the 19th century up until the mid-1970s, when it started to be replaced by cement. Its widespread use is evident in the construction of old buildings, where it was employed in mortars, plasters, and whitewashing. Lime production was also extremely common on several islands within the Cape Verde archipelago. However, recent rehabilitation efforts on historical heritage have often overlooked this material, leading to premature degradation of building exteriors. Therefore, current awareness on production and use of air lime in the archipelago, promoting its contemporary application in restoration projects is the main aim of this paper. This study integrates the lime cycle throughout Cape Verde, focusing particularly on the islands Boa Vista, Santo Antão, and São Vicente, as main lime producers. The origins and characteristics of locally quarried limestone, air lime production techniques and the historical significance of this material in the region are analysed in this study. As the records of production and use of building materials are scarce, this research involves a mixed approach of site identification, analysis of raw materials, description of existing furnaces, interviews with local residents involved in lime production, and review of relevant literature.
Deposition of insoluble calcium phosphate layers by combining finely dispersed calcium hydroxide sols with soluble phosphates
Authors: Tigrano Antonia , Ziegenbalg Gerald
Published: September 2024

Carbonate containing materials are subject to severe weathering. Traditional formulations of stone strengtheners have low compatibility with the original material and further they contain VOCs (volatile organic compounds), which endanger human health and the environment.

This study explores the high potential of novel treatments based on water-soluble phosphates used as an agent to react with calcium carbonate (CaCO3) to form an insoluble film of calcium phosphate in the pore space of the treated material. Pretreatments with nanolime suspensions ensure greater availability of calcium ions and reduce the consumption of the original material in the reactions. An alkaline environment is required to promote the conversion of the CaCO3 components to hydroxyapatite-like compounds. Based on experiments in aqueous solutions, different sources of phosphate ions could be examined and compared for the development of effective treatments to apply on different test specimens. To implement the treatments, barium phosphate solutions were investigated. Important aspects of this research are the use of green solvents and the search of components that avoid the formation of byproducts, to increase the efficiency of the chemical reactions and reduce possible negative effects on the operator, the environment and the very same built heritage material.

The developed treatments are a valuable alternative to the traditional methods, as it follows an improvement in the material properties without affecting the moisture transport within it and allows the evenly reaction of the strengthened material to external physical and mechanical stresses without creating internal tension between the grains.
Prise en charge anesthésique du chien et du chat diabétiques
Authors: Manjon-Aspe Ada , Marotto Stéphanie
Published: September 2024

L’anesthésie du chien ou du chat atteints de diabète sucré peut constituer un défi, car elle présente un risque accru de complications. De plus, l’animal peut présenter des comorbidités, qui vont influer sur le risque anesthésique préexistant. Il est nécessaire d’avoir connaissance du cadre clinique complet afin de se préparer de façon optimale à la gestion des complications peranesthésiques. La stabilisation de la glycémie et la planification de la procédure sous anesthésie sont recommandées à chaque fois que cela est possible, afin de diminuer la morbi-mortalité.
Introduction aux résections apicales chez le lapin et les Caviomorphes
Authors: Rosas-Navarro José
Published: September 2024

Les maladies dentaires sont courantes chez de nombreuses espèces de mammifères exotiques de compagnie, en particulier les Lagomorphes et les Caviomorphes à dentition élodonte (croissance continue), comme les lapins, cobayes, chinchillas et octodons. Malgré une meilleure prévention et un meilleur traitement, la gestion des maladies dentaires reste toujours un défi pour le propriétaire de l’animal comme pour le vétérinaire. Des complications post-chirurgicales et des récidives peuvent survenir et être à l’origine de chirurgies dentaires répétées sous anesthésie générale. Un tel résultat peut entraîner un coût important pour le propriétaire et un risque anesthésique croissant pour le patient. En dentisterie vétérinaire, on utilise régulièrement l’apicectomie, qui consiste à extraire la pointe de la « racine » (couronne de réserve) de la dent infectée ou fracturée. L’apicectomie chez les Lagomorphes et les Caviomorphes est une technique peu décrite dans la littérature. Il s’agit cependant d’une option thérapeutique qui offre une alternative très intéressante à l’extraction dentaire chez ces espèces.
Alobophora sandrae n. gen. n. sp. (Digenea: Caballerotrematidae) infecting Arapaima gigas sensu lato (Osteoglossiformes: Arapaimidae) with a revision of Caballerotrema, key to Caballerotrematidae, and updated phylogeny
Authors: Cajiao-Mora Kamila , Brule John H. , Warren Micah B. , Ksepka Steven P. , Dutton Haley R. , Bullard Stephen A.
Published: September 2024

We propose and describe Alobophora sandrae Cajiao-Mora & Bullard n. gen., n. sp. (Digenea: Caballerotrematidae) for specimens we collected from arapaima, Arapaima gigas sensu lato (Osteoglossiformes: Arapaimidae) in the Amazon River near Leticia, Colombia. Alobophora differs from Caballerotrema Prudhoe, 1960 by lacking head collar projections and by having clustered corner spines and a narrow head collar (4–5× wider than pharynx), whereas Caballerotrema has head collar projections, lacks clustered corner spines, and has a broad head collar (7–8× wider than pharynx). We reassign Caballerotrema annulatum (Diesing, 1850) Ostrowski de Núñez & Sattmann, 2002 to the new genus, as Alobophora annulata (Diesing, 1850) Cajiao-Mora and Bullard n. comb., and provide a supplemental description of Caballerotrema brasiliense Prudhoe, 1960 based on specimens we collected from arapaima. We also examined the holotype and a paratype of Caballerotrema piscicola (Stunkard, 1960) Kostadinova & Gibson, 2001 and concluded that C. piscicola is a junior subjective synonym of C. brasiliense. Our 28S phylogeny recovered A. sandrae sister to A. annulata, with that clade sister to a clade comprising C. brasiliense and an innominate species of Caballerotrema. Caballerotrematidae was recovered sister to Echinostomatidae. We also provide a dichotomous key to caballerotrematids based on head collar projections, corner spine arrangement, proportional pharynx and head collar breadth, testes shape and arrangement, body surface spine shape and distribution, vitellarium distribution, and abundance of prostatic cells.
Restricted maximum of non-intersecting Brownian bridges
Authors: Yalanda Yamit , Zalduendo Nicolás
Published: September 2024

Consider a system of N non-intersecting Brownian bridges in [0,1], and let ℳN(p) be the maximal height attained by the top path in the interval [0, p], p ∈ [0, 1]. It is known that, under a suitable rescaling, the distribution of ℳN(p) converges, as N → ∞, to a one-parameter family of distributions interpolating between the Tracy-Widom distributions for the Gaussian Orthogonal and Unitary Ensembles (corresponding, respectively, to p → 1 and p → 0). It is also known that, for fixed N, ℳN(1) is distributed as the top eigenvalue of a random matrix drawn from the Laguerre Orthogonal Ensemble. Here we show a version of these results for ℳN(p) for fixed N, showing that ℳN(p) / √p converges in distribution, as p → 0, to the rightmost charge in a generalized Laguerre Unitary Ensemble, which coincides with the top eigenvalue of a random matrix drawn from the Antisymmetric Gaussian Ensemble.
Temporal optimization of movement regulations in ball sports experts revealed by a visuo-manual pursuit task
Authors: Mallek Maroua , Thouvarecq Régis , Habacha Hamdi , Benguigui Nicolas
Published: September 2024

The present work focuses on the effect of expertise in ball sports on the perceptual-motor processes. Non-Experts, Experts and Super-Experts were evaluated through a visuo-manual tracking task in a 2D environment, with more or less predictable trajectories (predictable bounces and unpredictable deviations). The results showed that this task, as schematic as it may be, allows the discrimination of expertise in ball sports. Moreover, the multiple regression analysis revealed that the performance could be explained by the frequency of the regulations and the temporal delays to perform them. Our results highlight the optimized perception-action coupling of experts.
Schnelle Schritte nach der Sommerpause
Authors: Lukuc Sarah
Published: September 2024

Schon vor der Sommerpause kündigte Bundesgesundheitsminister Lauterbach das Pflegekompetenzgesetz an. Dieses Versprechen hat er leider nicht gehalten. Dafür hat der Minister jetzt, innerhalb von einer Woche, die ausstehenden Referentenentwürfe zur Pflegefachassistenzausbildung und zum Pflegekompetenzgesetz vorgelegt.
Aus der Pflege für die Pflege
Authors: Lukuc Sarah , Roßius Sabrina
Published: September 2024

Als Standardeigner hat der Bundesverband Pflegemanagement mit unterschiedlichen ­Akteuren aus der
Gesundheitsversorgung Kriterien erarbeitet, die einen attraktiven Arbeit­geber ausmachen. Die
Ausgestaltung erfolgt individuell vor Ort in den Kliniken.
Monitoring Anesthetic Depth Using the Patient State Index in
Electroconvulsive Therapy Improves Seizure Quality
Authors: Alcoverro-Fortuny Oscar , Viñas Usan Ferran , Sanabria Carmen E. , Esnaola Mikel , E. Rojo Rodes José
Published: September 2024

Objectives The determination of anesthetic depth has been used to assess
the optimal moment for applying electrical stimuli in electroconvulsive therapy
(ECT), as some of the anesthetics used can reduce its effectiveness. In this
study, seizure quality was assessed using anesthetic depth measurement with the
patient state index (PSI).

Methods A prospective experimental study was conducted with a control
group, including a sample of 346 stimulations (PSI=134; Control=212) in 51
patients admitted and diagnosed with major depressive disorders. Seizure
adequacy variables (seizure time in electroencephalogram [EEG] and motor
activity, visual evaluation of the EEG, ECT-EEG parameter rating scale [EEPRS],
seizure concordance, central inhibition, automated parameters, and autonomic
activation) were assessed using linear mixed-effects models for continuous
variables and generalized linear mixed-effects models for dichotomous
variables.

Results The PSI group required lower stimulation energy. The use of the
PSI was associated with longer seizure time, both motor and
electroencephalographic, higher quality of the EEG recording, better seizure
concordance, and higher values for the automated parameters of maximum sustained
coherence and time to peak coherence.

Conclusions The use of the PSI to measure anesthetic depth may reduce the
electrical stimulus charge required and improve seizure quality in ECT modified
with propofol.
Physical Activity Levels in Children with Esophageal Atresia and Congenital Heart Disease: A Comparative Multicenter Study
Authors: Frankenbach Luisa Maria , Holler Anne-Sophie , Oetzmann von Sochaczewski Christina , Wessel Lucas , Muensterer Oliver J. , Dingemann Jens , Widenmann Anke , Helm Paul , Siaplaouras Jannos , Bauer Ulrike , Apitz Christian , Niessner Claudia , König Tatjana Tamara
Published: September 2024

Aim of the Study Esophageal atresia (EA) is associated with impaired motor development, cardiopulmonary function, and physical activity (PA). Despite missing scientific evidence, this fact is often attributed to associated congenital heart disease (CHD). The aim of this study was to investigate PA in EA patients without CHD compared with CHD patients and healthy controls.

Methods In this multicenter study, EA patients aged 6 through 17 years were included. Moderate-to-vigorous PA (MVPA, minutes per week) was assessed using the standardized and validated questionnaire Motorik-Modul Physical Activity Questionnaire. EA patients were randomly matched 1:4 for gender and age with patients with CHD (n = 1,262) and healthy controls (n = 6,233). Patients born with both EA and CHD were excluded. Means and 95% confidence intervals (95% CIs) were calculated. To identify associated factors, Spearman's correlation was performed.

Main Results Overall, 69 EA patients were matched with 276 CHD patients and 276 controls (57% male, 43% female, mean age 10,3 years, 95% CI: 9.5–11.1). Mean MVPA was reduced in EA (492 minutes, 95% CI: 387–598) and CHD patients (463 minutes, 95% CI: 416–511) compared with controls (613 minutes, 95% CI: 548–679). In subgroup analysis, MVPA was reduced further in females and older age groups with EA and CHD. For EA patients, there was no statistical association between Gross type, current symptoms, surgical approaches, and MVPA.

Conclusion Isolated EA and CHD were associated with reduced PA, especially in females and teenagers. To avoid additional morbidity associated with sedentary behavior, PA should be promoted during follow-up.
Synthesis of Diaryl Diselenides and Ditellurides via Bromide-Catalyzed C–Se/C–Te Bond Formation Using Se/Te Powder and Boronic Acid
Authors: Cai Jinhui , Shen Wangzhen , Cen Kaili , Zeng Zhouting
Published: September 2024

Diaryl diselenides and diaryl ditellurides are commonly employed as selenyl or telluryl sources, and they have a wide range of applications in organic synthesis. Herein, various diaryl diselenides/ditellurides are furnished in moderate to excellent yields under metal-free conditions. This method features high efficiency, good functional group tolerance, straightforward operation, and easy scale-up (running in 4 mmol-scale for most cases). Mechanistic studies indicate that this reaction may proceed via a radical pathway. Significantly, the correct matching of Br– and dimethyl sulfoxide under an air atmosphere is critical to this transformation.
Fantasies and Fallacies of ‘Aesthetic’ Instagrammers
Authors: Sharma Mrigya , Dhakad Abhishek , Sharma Sandeep
Published: September 2024

The influence of Instagram, as a social media platform, in shaping perceptions of aesthetic surgery cannot be understated. The idea of a more “aesthetic” self cultivates a desire for cosmetic enhancements. This article underscores the profound impact of Instagram on aesthetic surgery, shedding light on both its fantasies and fallacies. Instagram, a medium for dissemination of content, often blurs the lines between fantasy and reality. Although the intent is to transfer credible information from the provider to the consumer, Instagram often contributes to the distortion of one's self-image and creates unrealistic expectations. Moreover, the glamorization of aesthetic surgery as a fast, effortless fix, often by commercially run enterprises, leads to misconceptions and impulsive decision-making. These fallacies are further compounded by the increase of misinformation and deceptive practices, presenting ethical challenges for influencers and surgeons alike. This study explores the ethical responsibilities of these “Aesthetic Instagrammers,” emphasizing the necessity for transparency and ethical guidelines, while analyzing all the social media stakeholders and providing suggestions for better engagement.
Global large solutions for the nonlinear dissipative system modeling electro-hydrodynamics
Authors: Cai Zhongbo , Li Ying , Zhao Jihong
Published: September 2024

In this paper, we are concerned with global existence of large solutions for a dissipative model arising from electro-hydrodynamics, which is the nonlinear nonlocal system coupled by the Poisson–Nernst–Planck equations and the incompressible Navier–Stokes equations through charge transport and external forcing terms. By introducing some proper weighted functions and fully using the algebraic structure of the system, we prove that, under some conditions imposed on the indices p, p1, q, r, α, there exist two positive constants c0, C0 such that if the initial data u0=(u0h,u03) and (v0, w0) satisfy ‖u0h‖Ḃp1,∞−1+3p1+‖u0h‖Ḃp1,∞−1+3p1α‖u03‖Ḃp1,∞−1+3p11−α+K0≤c0 with K0≔‖v0‖Ḃq,1−2+3q⁡expC0‖u0‖Ḃp,1−1+3p+C0‖w0‖Ḃr,1−2+3r+1expC0‖u0‖Ḃp,1−1+3p, then the system admits a unique global solution. Moreover, the global existence of large solution was also established in two dimensional case.
Global existence of non-Newtonian incompressible fluid in half space with nonhomogeneous initial-boundary data
Authors: Chang Tongkeun , Jin Bumja
Published: September 2024

In this study, we investigate the global existence of weak solutions of non-Newtonian incompressible fluids governed by (1.1). When u0∈Ḃp,qα−2p(R+n)∩Ḃn+22,n+221−4n+2(R+n)∩Ḃp,11+np(R+n) is given, we will find the weak solutions for the Eq. (1.1) in the function space Cb[0,∞;Ḃp,qα−2p(R+n)∩Cb(0,∞;Ḃn+221−4n+2(R+n))∩L∞(0,∞;Ẇ∞1(R+n)), n+2<p<∞,1≤q≤∞,1+n+2p<α<2. We show the existence of weak solutions in the anisotropic Besov spaces Ḃp,qα,α2(R+n×(0,∞)) (see Theorem 1.2) and we show the embedding Ḃp,qα,α2R+n×(0,∞)⊂Cb[0,∞;Ḃp,qα−2p(R+n) (see Lemma 2.8). For the global existence of solutions, we assume that the extra stress tensor S is represented by S(A)=F(A)A, where F satisfies the assumption (A). Note that S1, S2 and S3 introduced in (1.2) satisfy our assumptions.
Mechanically activated and deactivated ion transport across nanopores with heterogeneous surface charge distributions
Authors: Paul Arghyadeep , Aluru N. R.
Published: September 2024

To mimic the intricate and adaptive functionalities of biological ion channels, electrohydrodynamic ion transport has been studied extensively, albeit mostly, across uniformly charged nanochannels. Here, we analyze the ion transport under coupled electric field and pressure across heterogeneously charged nanopores with oppositely charged sections on their lateral surface. We only consider such pores with symmetric hourglass-like and cylindrical shapes to focus on the effects of the non-uniform surface charge distribution. Finite-element simulations of a continuum model demonstrate that a pressure applied in either direction of the pore-axis equally suppresses or amplifies the ionic conductance, depending on the electric field polarity, by distorting the quasi-static distribution of ions in the pore. The resulting anomalous mechanical deactivation and activation of ionic current under opposite voltage biases exhibit the functional modularity of our setup, while their intensities are highly tunable, substantially greater than those of analogous behaviors in other nanochannels, and fundamentally correlated to ionic current rectification (ICR) in our pores. A detailed study of ICR subsequently reveals its counterintuitive non-monotonous variations, in the pores, with the magnitude of applied voltage and the pore length, that can help optimize their diode-like behavior. We further illustrate that while the hourglass-shaped nanopores yield the more efficient mechanical suppressors of ion transport, their cylindrical analogs are the superior rectifiers and mechanical amplifiers of ion conduction. Therefore, this article provides a blueprint for the strategic design of nanofluidic circuits to attain a robust, modular, and tunable control of ion transport under external electrical and mechanical stimuli.
Thermodynamic dissipation does not bound replicator growth and decay rates
Authors: Kolchinsky Artemy
Published: September 2024

In a well-known paper, Jeremy England derived a bound on the free energy dissipated by a self-replicating system [J. L. England, “Statistical physics of self-replication,” J. Chem. Phys. 139, 121923 (2013)]. This bound is usually interpreted as a universal relationship that connects thermodynamic dissipation to replicator per-capita decay and growth rates. We argue from basic thermodynamic principles against this interpretation. In fact, we suggest that such a relationship cannot exist in principle, because it is impossible for a thermodynamically consistent replicator to undergo both per-capita growth and per-capita decay back into reactants. Instead, replicator may decay into separate waste products, but in that case, replication and decay are two independent physical processes, and there is no universal relationship that connects their thermodynamic and dynamical properties.
Simultaneous high-throughput particle-bacteria separation and solution exchange via in-plane and out-of-plane parallelization of microfluidic centrifuges
Authors: Norouzy Nima , Zabihihesari Alireza , Rezai Pouya
Published: September 2024

Inertial microfluidic devices have gained attention for point-of-need (PoN) sample preparation. Yet, devices capable of simultaneous particle-bacteria solution exchange and separation are low in throughput, hindering their applicability to PoN settings. This paper introduces a microfluidic centrifuge for high-throughput solution exchange and separation of microparticles, addressing the need for processing large sample volumes at elevated flow rates. The device integrates Dean flow recirculation and inertial focusing of microparticles within 24 curved microchannels assembled in a three-layer configuration via in-plane and out-of-plane parallelization. We studied solution exchange and particle migration using singleplex and duplex samples across devices with varying curve numbers (2-curve, 8-curve, and 24-curve). Processing 5 and 10 μm microparticles at flow rates up to 16.8 ml/min achieved a solution exchange efficiency of 96.69%. In singleplex solutions, 10 and 5 μm particles selectively migrated to inner and outer outlets, demonstrating separation efficiencies of 99.7% and 90.3%, respectively. With duplex samples, sample purity was measured to be 93.4% and 98.6% for 10 and 5 μm particles collected from the inner and the outer outlets, respectively. Application of our device in biological assays was shown by performing duplex experiments where 10 μm particles were isolated from Salmonella bacterial suspension with purity of 97.8% while increasing the state-of-the-art particle solution exchange and separation throughput by 16 folds. This parallelization enabled desirable combinations of high throughput, low-cost, and scalability, without compromising efficiency and purity, paving the way for sample preparation at the PoN in the future.
Koopman analysis of the singularly perturbed van der Pol oscillator
Authors: Katayama Natsuki , Susuki Yoshihiko
Published: September 2024

The Koopman operator framework holds promise for spectral analysis of nonlinear dynamical systems based on linear operators. Eigenvalues and eigenfunctions of the Koopman operator, the so-called Koopman eigenvalues and Koopman eigenfunctions, respectively, mirror global properties of the system’s flow. In this paper, we perform the Koopman analysis of the singularly perturbed van der Pol system. First, we show the spectral signature depending on singular perturbation: how two Koopman principal eigenvalues are ordered and what distinct shapes emerge in their associated Koopman eigenfunctions. Second, we discuss the singular limit of the Koopman operator, which is derived through the concatenation of Koopman operators for the fast and slow subsystems. From the spectral properties of the Koopman operator for the singularly perturbed system and the singular limit, we suggest that the Koopman eigenfunctions inherit geometric properties of the singularly perturbed system. These results are applicable to general planar singularly perturbed systems with stable limit cycles.
Size and velocity of jet drops produced by bursting bubbles at the interface of a water jet
Authors: Succar Antonella , Prévost Michèle , Bédard Emilie , Robert Etienne
Published: September 2024

Bursting bubbles at the free surface of aerated faucet water jets may spread pathogens through the released droplets. Many studies focused on the production of jet drops from bursting bubbles at a planar interface, particularly for the first jet drop. The extent to which previous findings apply to bubbles in aerated jets remains unknown. In this study, we produce a wide range of bubble size distributions within different jet diameters and characterize the diameter and velocity of jet drops released from individually bursting bubbles. Several similarities with the planar case are recovered, such as the overall dependence of the jet drop diameter and bursting dynamics on the bubble diameters and the formation of secondary jet drops. However, we observe asymmetries in the ejection of the droplets, and droplets ejected horizontally appear to have the highest ejection velocity among all jet drops. By modeling the evolution of the ejected drops for the different bubble size distributions, we find that for a mean Laplace number Labub=ρwσwRbubμw2≲6×104, a fraction of the drops ejected can become airborne. Droplets deposit within 9 cm for a mean Labub≲2.1×104 and within 33 cm for a mean 2.1×104≲Labub≲1.8×105 from a faucet jet, assuming a countertop situated 20 cm below the faucet outlet. A bubble size distribution with a mean Labub of 6×104 would minimize both the risk of airborne pathogen transmission and that resulting from surface contamination.
Growth of [001]-oriented polycrystalline Heusler alloy thin films using [001]-textured Ag buffer layer on thermally oxidized Si substrate for spintronics applications
Authors: Taparia Dolly , Sasaki Taisuke T. , Nakatani Tomoya , Suto Hirofumi , Mitani Seiji , Sakuraba Yuya
Published: September 2024

To utilize highly spin-polarized Heusler alloys in practical spintronic devices, the realization of highly textured and structurally ordered polycrystalline thin films under limited annealing temperatures (TA) is critical. Compared to the natural [110]-texture of Heusler alloys, the [001]-texture is considered to be favorable for current-perpendicular-to-plane giant magnetoresistance devices due to the reduced lattice misfit with the face-centered-cubic Ag spacer layers. In this study, we fabricated [001]-oriented polycrystalline Co2FeGa0.5Ge0.5 (CFGG) Heusler alloy films epitaxially grown on a [001]-oriented polycrystalline Ag buffer layer on a thermally oxidized Si substrate, and the microstructure of the [001]-oriented Ag/CFGG bilayer film was investigated in detail. The [001]-oriented Ag films were obtained by introducing N2 into Ar during the sputtering process. The [001]-oriented CFGG films exhibited smooth interfaces, B2 ordering, and a high saturation magnetization close to the theoretical value under relatively low annealing at TA = 300 °C, which are critical for industrial applications such as read heads of hard disk drives.
Modulation instability and rogue waves for two and three dimensional nonlinear Klein–Gordon equation
Authors: Yang Zhiqiang , Mu Gui , Qin Zhenyun
Published: September 2024

We perform the modulation instability analysis of the 2D and 3D nonlinear Klein–Gordon equation. The instability region depends on dispersion and wavenumbers of the plane wave. The N-breathers of the nonlinear Klein–Gordon equation are constructed directly from its 2N-solitons obtained in history. The regularity conditions of breathers are established. The dynamic behaviors of breathers of the 2D nonlinear Klein–Gordon equation are consistent with modulation instability analysis. Furthermore, by means of the bilinear method together with improved long-wave limit technique, we obtain general high order rogue waves of the 2D and 3D nonlinear Klein–Gordon equation. In particular, the first- and second-order rogue waves and lumps of the 2D nonlinear Klein–Gordon equation are investigated by using their explicit expressions. We find that their dynamic behaviors are similar to the nonlinear Schrödinger equation. Finally, the first-order rational solutions are illustrated for the 3D nonlinear Klein–Gordon equation. It is demonstrated that the rogue waves of the 2D and 3D nonlinear Klein–Gordon equation always exist by choosing dispersion and wavenumber of plane waves.
Modulational instability of a pair of collinear wave trains
Authors: Chakrabortty Sabyasachi , Debsarma Suma
Published: September 2024

A coupled system of three nonlinear evolution equations is derived for a pair of collinear wave packets over finite depth fluid. The wave packets are narrow banded having different carrier wave frequencies. The evolution equations are employed to perform stability analysis of a pair of collinear wave trains. It is observed that the region of instability as well as the growth rate of instability for counter-propagating waves is greater than that for co-propagating waves when everything else remains same. The region of instability increases with the increase in the depth of the medium. It is also found that the growth rate of instability of a wave train increases with the increase in wave-steepness of the second wave train.
Delineation of the impact on temporal behaviors of off-axis photoemission in an ultrafast electron microscope
Authors: Chen Jialiang , Willis Simon A. , Flannigan David J.
Published: September 2024

Efforts to push the spatiotemporal imaging-resolution limits of femtosecond laser-driven ultrafast electron microscopes (UEMs) to the combined angstrom–fs range will benefit from stable sources capable of generating high bunch charges. Recent demonstrations of unconventional off-axis photoemitting geometries are promising, but connections to the observed onset of structural dynamics are yet to be established. Here we use the in-situ photoexcitation of coherent phonons to quantify the relative time-of-flight (r-TOF) of photoelectron packets generated from the Ni Wehnelt aperture and from a Ta cathode set-back from the aperture plane. We further support the UEM experiments with particle-tracing simulations of the precise electron-gun architecture and photoemitting geometries. In this way, we measure discernible shifts in electron-packet TOF of tens of picoseconds for the two photoemitting surfaces. These shifts arise from the impact that the Wehnelt-aperture off-axis orientation has on the electron-momentum distribution, which modifies both the collection efficiency and the temporal-packet distribution relative to on-axis emission. Future needs are identified; we expect this and other developments in UEM electron-gun configuration to expand the range of material phenomena that can be directly imaged on scales commensurate with fundamental structural dynamics.
A hydrophilic porous graphene aerogel electrode with a large specific surface area for high-performance all-aqueous thermally regenerative batteries
Authors: Zhang Liang , An Yichao , Shi Yu , Li Jun , Zhu Xun , Liao Qiang
Published: September 2024

All-aqueous thermally regenerative batteries (ATRBs) have shown great potential in harvesting low-grade waste heat. In this study, a hydrophilic porous graphene aerogel (GA) electrode developed by an ice template was developed for ATRBs to enhance electricity generation. The physicochemical property of GA was analyzed by traditional characterization. The main functional group of GA was N–H, which offered ATRBs a high hydrophilic surface. As a result of the ice templates, the diameter of pores in GA was almost lower than 4 nm, which provided a high specific area and good wettability. In addition, density functional theory calculations were carried out to verify the superiority of good electrical conductivity and strong adsorption on the cupric ions. Therefore, ATRB with GA achieved a competitive performance (a peak power density of 432 W/m2), illustrating great potential in the future thermoelectricity conversion application.
Microscopic characteristics of SF6 partial discharge induced by a floating linear metal particle
Authors: Feng Zihao , Jiang Yuanyuan , Zhang Liyang , Liu Zhigang , Wang Kai , Wang Xinxin , Zou Xiaobing , Luo Haiyun , Fu Yangyang
Published: September 2024

Direct current (DC) gas insulated transmission lines (GILs) have been widely used in power transmission but might be threatened by partial discharge due to the presence of floating impurities (e.g., dust and metal particles) inside the sealed chamber. In this Letter, by using a 2D fluid model, we characterize the microscopic properties of the partial discharge induced by a floating linear metal particle in SF6 (both the discharge propagation and interaction between space charge and metal particle) under negative high voltage direct current conditions. Due to the strong electronegativity of SF6, the spatiotemporal distributions of the charged species (electrons, positive ions, and negative ions), space charge, and reduced electric field are rather different from those in air. Notably, a negative ion region is observed around the top tip of the metal particle, and it plays an important role in the generation and propagation of primary and secondary streamers in SF6, which may lead to severe motion characteristics of the particle and aliasing of partial discharge signals. Additionally, we analyze the charging process and electric force reversal phenomenon, which may provide a more precise understanding of the underlying mechanisms of the firefly motion previously reported for DC GILs.
Stimulated Raman scattering of a broadband chirped Ti:sapphire laser pulse in calcite seeded by a narrowband nanosecond Nd:YAG laser pulse
Authors: Kinyaevskiy Igor O. , Kovalev Valeri I. , Koribut Andrew V. , Grudtsyn Yakov V.
Published: September 2024

Stimulated Raman Scattering (SRS), pumped by a broadband (i.e., compared to the bandwidth of the material excitation) chirped 50-ps pulse, with Stokes seeding by a 20-ns narrowband pulse, is experimentally and theoretically investigated. In the experiments, a femtosecond-class 0.95 μm Ti:sapphire laser system and a Q-switched 1.064 μm Nd:YAG laser were used for pumping and seeding SRS in a calcite (CaCO3) crystal. This material was chosen because its Raman resonance frequency (∼1089 cm−1) is near to the frequency difference between the pump and seed radiation. It is shown that, despite a narrowband seed, the generated Stokes pulse spectrum mimics the pump pulse spectral width. The observed SRS conversion efficiency saturates at 40%, with a weak dependence on the seed pulse energy and on the detuning of the pump-seed frequency from the Raman resonance. Theoretical modeling confirms the observed effects and permits prediction of the characteristics of the investigated system as its parameters are varied.
Large/small eddy simulations: A high-fidelity method for studying high-Reynolds number turbulent flows
Authors: Moitro Arnab , Dammati Sai Sandeep , Poludnenko Alexei Y.
Published: September 2024

Direct numerical simulations (DNS) are one of the main ab initio tools to study turbulent flows. However, due to their considerable computational cost, DNS are primarily restricted to canonical flows at moderate Reynolds numbers, in which turbulence is isolated from the realistic, large-scale flow dynamics. In contrast, lower fidelity techniques, such as large eddy simulations (LES), are employed for modeling real-life systems. Such approaches rely on closure models that make multiple assumptions, including turbulent equilibrium, small-scale universality, etc., which require prior knowledge of the flow and can be violated. We propose a method, which couples a lower-fidelity, unresolved, time-dependent calculation of an entire system (LES) with an embedded small eddy simulation (SES) that provides a high-fidelity, fully resolved solution in a sub-region of interest of the LES. Such coupling is achieved by continuous replacement of the large SES scales with a low-pass filtered LES velocity field. The method is formulated in physical space, with no assumptions of equilibrium, small-scale structure, and boundary conditions. A priori tests of both steady and unsteady homogeneous, isotropic turbulences are used to demonstrate the method's accuracy in recovering turbulence properties, including spectra, probability density functions of the intermittent quantities, and sub-grid dissipation. Finally, SES is compared with two alternative approaches: one embedding a high-resolution region through static mesh refinement and a generalization of the traditional volumetric spectral forcing. Unlike these methods, SES is shown to achieve DNS-level accuracy at a fraction of the cost of the full DNS, thus opening the possibility to study high-Re flows.
Environment-mediated long-ranged correlations in many-body system
Authors: Xu Meng , Stockburger J. T. , Ankerhold J.
Published: September 2024

Quantum states in complex aggregates are unavoidably affected by environmental effects, which typically cannot be accurately modeled by simple Markovian processes. As system sizes scale up, nonperturbative simulation becomes thus unavoidable, but they are extremely challenging due to the intimate interplay of intrinsic many-body interaction and time-retarded feedback from environmental degrees of freedom. In this work, we utilize the recently developed quantum dissipation with minimally extended state space approach to address reservoir induced long-ranged temporal correlations in finite size Ising-type spin chains. For thermal reservoirs with ohmic and subohmic spectral density, we simulate the quantum time evolution from finite to zero temperature. The competition between thermal fluctuations, quantum fluctuations, and anti-/ferromagnetic interactions reveals a rich pattern of dynamical phases, including dissipative induced phase transitions and spatiotemporal correlations.