Laboratory Simulation Research Articles

Effect of Ladle Washing Operation on Non-metallic Inclusions in Tire Cord Steel: Laboratory Simulation

Effect of Ladle Washing Operation on Non-metallic Inclusions in Tire Cord Steel: Laboratory Simulation

Effect of barnacle on the cathodic protection of high-strength steel and its potential risk related to hydrogen permeation

The cathodic protection efficiency and hydrogen permeation behaviour of high-strength steel with barnacle adhesion in the tidal zone were studied using field exposure and laboratory simulation tests for 2 years. Because of the shielding effect, barnacles can lead to an uneven calcareous deposition, a flatter morphology and a higher protection efficiency of steel. By contrast, because of the higher hydrogen permeation current at the edge of the barnacle adhesion area (caused by a higher hydrogen evolution rate), barnacle adhesion can promote hydrogen permeation. A mechanism was proposed to explain the observed phenomenon, and its effect on service safety was analysed.

Ionizing radiation exposure on Arrokoth shapes a sugar world

The Kuiper Belt object (KBO) Arrokoth, the farthest object in the Solar System ever visited by a spacecraft, possesses a distinctive reddish surface and is characterized by pronounced spectroscopic features associated with methanol. However, the fundamental processes by which methanol ices are converted into reddish, complex organic molecules on Arrokoth's surface have remained elusive. Here, we combine laboratory simulation experiments with a spectroscopic characterization of methanol ices exposed to proxies of galactic cosmic rays (GCRs). Our findings reveal that the surface exposure of methanol ices at 40 K can replicate the color slopes of Arrokoth. Sugars and their derivatives (acids, alcohols) with up to six carbon atoms, including glucose and ribose-fundamental building block of RNA-were ubiquitously identified. In addition, polycyclic aromatic hydrocarbons (PAHs) with up to six ring units (13C22H12) were also observed. These sugars and their derivatives along with PAHs connected by unsaturated linkers represent key molecules rationalizing the reddish appearance of Arrokoth. The formation of abundant sugar-related molecules dubs Arrokoth as a sugar world and provides a plausible abiotic preparation route for a key class of biorelevant molecules on the surface of KBOs prior to their delivery to prebiotic Earth.

Laboratory-accelerated simulation and calibration method for ultraviolet aging of asphalt binders based on radiation equivalent conversion

Ultraviolet (UV) radiation is a significant environmental factor that accelerates the aging of asphalt pavements. To address the gap in the equivalence conversion relationship between laboratory simulation parameters and field environmental factors for asphalt pavement aging in the Tibet area of China, this study investigates the relationship between laboratory simulations and field service for asphalt aging. The results indicate that using macroscopic rheological parameters (rutting factor (G*/sin δ), average recovery rate (R), and average non-recoverable creep compliance (Jnr)) and microscopic parameters (sulfoxide index (SI) and glass transition temperature (Tg)) as quantitative indicators can evaluate the equivalent degrees of laboratory and field aging. Furthermore, this study introduces a correction coefficient for laboratory-accelerated simulated aging to improve the accuracy of the equivalent radiation conversion formula. The correction coefficient range for 90# matrix asphalt is 1.36–2.05, while the range for SBS modified asphalt is 0.82–1.64. This study provides a valuable database for establishing the relationship between laboratory simulations and field service for asphalt aging and offers a parameter basis and technical support for designing durable asphalt pavements in areas with intense UV radiation.

Using construction and demolition waste materials to alleviate the negative effect of pavements on the urban heat island: A laboratory, field, and numerical study

In this study, construction and demolition waste (CDW) materials, including waste clay bricks, concrete, and glass, were used as aggregates of chip seal layers to enhance the reflectivity and reduce the temperature of asphalt pavements as an urban heat island (UHI) mitigation policy. UHI is an urban area that has a higher temperature in comparison to its suburbs. As considerable parts of cities are covered with asphalt pavements, their heat absorption and heat release can directly affect the UHI. Four types of chip seal layers, containing CDW aggregates were prepared in this study. The reflectivity and cooling effects of asphalt pavement coated with the developed chip seals were then evaluated with laboratory, field experiments, and computational fluid dynamics (CFD) simulation. Regarding the laboratory methods, UV-Visible-NIR spectrometer reflectance, a trident thermal properties measurement, and solar simulation cooling effect were used. Besides, the albedo and cooling effects of the developed chip seals were evaluated with a pyranometer and thermocouples through a field experiment. The indoor reflectance test showed yellow and red brick chip seals reflected almost 136 % higher than the aged asphalt pavement, followed by concrete chip seals with 80 % higher solar reflectance. Besides, the surface temperatures of yellow brick, red brick, and concrete chip seals were 23 %, 18 %, and 15 % cooler than the hot mix asphalt (HMA) specimens. More importantly, clay brick chip seals had the lowest nighttime heat release, followed by the concrete chip seal. The field test indicated that the albedo of yellow brick was 2 and 6 times higher than the aged and new HMA, causing 17 % and 27 % lower surface temperatures. The numerical models also revealed that using the yellow brick and concrete chip seals decreased the surrounding air temperature at least by 18 % and 14 % respectively. Overall, the numerical modeling, laboratory, and field tests showed similar results, indicating the benefits of using clay bricks and concrete aggregates for chip seal development, which can mitigate the UHI effectively.

Laboratory simulations of ice growth in space: An expected nonuniform ice mantle composition

Context. In dense, cold molecular regions, gas-phase chemical species freeze out onto grain surfaces. These icy condensates become an important reservoir of volatile elements and feedstock for molecular diversity. Aims. While there is a fairly general agreement on the chemical composition of icy mantles, there are differences in how the various molecular components are perceived to be present. Should the materials composing the ice be mixed or are they segregated into distinct chemical zones? Methods. To answer such a question, we performed a few exploratory experiments that allowed the adsorbing surface (mimic dust grains) to slowly relax to very low temperatures while gas-phase mixtures of H2O, NH3, and CO embed onto it. Results. We find that mantles are far from being uniform, and they could evolve into completely mixed ices only if the ambient temperature undergoes a catastrophic collapse. Conclusions. Under the typical conditions of an interstellar dense cloud, ices present a high degree of molecular segregation, with possible consequences on the ice chemistry and the desorption mechanisms.

Degradation, transformation and cytotoxicity of triphenyl phosphate on surface of different transition metal salts in atmospheric environment

Triphenyl phosphate (TPhP) and transition metal elements have been ubiquitously detected in the atmosphere, which can participate in atmospheric chemical reactions and induce damage to human health. Currently the understanding of TPhP degradation, transformation and cytotoxicity on atmospheric particles surface are still limited. Therefore, this study used laboratory simulation methods to investigate the influence of irradiation time, transition metal salts, relative humidity (RH) to TPhP degradation, transformation and relative cytotoxicity. TPhP was coated on particle surfaces of four transition metal salts (MnSO4, CuSO4, FeSO4 and Fe2(SO4)3) in the experiment. Within 12 h irradiation, the significant TPhP photodegradation can be observed on all particles surface. Among these influence factors, the irradiation and RH were the crucial aspects to TPhP degradation, which primarily affect the OH concentration in the atmosphere. The transition metal elements only exhibited slightly catalytic effect to TPhP degradation. The mechanism study indicated that the major degradation products of TPhP are diphenyl hydrogen phosphate (DPhP) and OH-DPhP, which originated from the phenoxy bond cleavage and hydroxylation of TPhP induced by OH. As for the cytotoxicity to A549 cells, all the transition metal particles coated with TPhP can cause cellular injury, which was chiefly induced by the transition metal salt. The possible cytotoxicity mechanism of these particles to A549 cells can be attributed to the excessive reactive oxygen species (ROS) production. This study may provide a further understanding of TPhP degradation and related cytotoxicity with the coexistent transition metal salts in the atmosphere.

The survival, gene expression, and DNA methylation of Paralichthys olivaceus impacted by the decay of green tide and bacterial infection in both laboratory and field simulation experiments

The recurring appearance of Ulva prolifera green tides has become a pressing environmental issue, especially for marine transportation, tourism, and aquaculture in the stage of decomposition. An abundance of decaying U. prolifera leads to water acidification, hypoxia and pathogenic microorganism proliferation, threatening marine germplasm resources, particularly benthic organisms with weak escape ability. Epigenetic modification is considered to be one of the molecular mechanisms involved in the plastic adaptive response to environmental changes. However, few studies concerning the specific impact of decaying green tide on benthic animals at the epigenetic level. In this study, decomposing algal effluents of U. prolifera, sediments containing uncorrupted U. prolifera, pathogenic microorganism were considered as impact factors, to reveal the effect of decaying U. prolifera on marine economic benthic species, Paralichthys olivaceus, using both field and laboratory simulation experiments. Field simulation experiment showed higher mortality rates and serious histopathological damage than the laboratory simulation experiment. And both the decaying U. prolifera and the sediment containing U. prolifera were harmful to P. olivaceus. Genome-wide DNA methylation and transcription correlation analyses showed that the response of P. olivaceus to green tide stress and bacterial infection was mainly mediated by immune signaling pathways such as PI3K-Akt signaling pathway. DNA methylation regulates the expression of immune-related genes involved in the PI3K-Akt signaling pathway, which enables P. olivaceus to adapt to the adverse environmental stresses by resisting apoptosis. In summary, this research analyzed the potential role of P. olivaceus in decaying U. prolifera, which is of great significance for understanding the impact of decaying green tide on marine commercial fish and also provides some theoretical guidance for the proliferation and release of fish seedlings.

Ship Bridge OOW Activity Status Detection Using Wi-Fi Beamforming Feedback Information

Officers on Watch (OOWs) of the ship’s bridge play a vital role in maritime navigation safety, monitoring the ship’s navigational status, and ensuring maritime safety. The status of inactive watch officers, such as fatigued driving and negligence on lookout, is one of the main causes of accidents. Intelligent technology for real-time perception and state evaluation of ship OOWs significantly reduces accidents caused by human factors. The traditional computer vision method is difficult to adapt to the complex environment of a ship bridge, and carries strong privacy risks. With the development of Internet of Things technology, sensing technology based on ubiquitous Wi-Fi devices provides a new way to accurately monitor the status of ship OOWs. In this paper, we use commercial off-the-shelf (COTS) Wi-Fi devices to propose a ship driving activity state detection method based on beamforming feedback information (BFI). Using wireless sensing data to sense the number of OOWs and their driving behavior realizes low-cost and high-precision detection of the behavioral status of the ship’s bridge watchkeeper. Experiments were conducted in a ship-driving simulation laboratory and on a real-world Yangtze River cruise ship. The experimental results demonstrate that our proposed method achieves 92.4% and 98.1% accuracy for tracking active status and estimating the number of OOWs, respectively.

Abiotic formation of alkylsulfonic acids in interstellar analog ices and implications for their detection on Ryugu

For the last century, the source of sulfur in Earth’s very first organisms has remained a fundamental, unsolved enigma. While sulfates and their organic derivatives with sulfur in the S(+VI) oxidation state represent core nutrients in contemporary biochemistry, the limited bioavailability of sulfates during Earth’s early Archean period proposed that more soluble S(+IV) compounds served as the initial source of sulfur for the first terrestrial microorganisms. Here, we reveal via laboratory simulation experiments that the three simplest alkylsulfonic acids—water soluble organic S(+IV) compounds—can be efficiently produced in interstellar, sulfur-doped ices through interaction with galactic cosmic rays. This discovery opens a previously elusive path into the synthesis of vital astrobiological significance and untangles fundamental mechanisms of a facile preparation of sulfur-containing, biorelevant organics in extraterrestrial ices; these molecules can be eventually incorporated into comets and asteroids before their delivery and detection on Earth such as in the Murchison, Tagish Lake, and Allende meteorites along with the carbonaceous asteroid Ryugu.

Soil erodibility by simulated rainfall in Latosols

Determining a soil's resistance to disaggregation and particle transport is a complex factor that depends on the interaction of multiple attributes. Therefore, this study aimed to determine the indirect and direct erodibility of Latosols in the suborders Red, Yellow and Red-Yellow in the state of Alagoas. The soils were identified through the modal profile of the Agroecological Zoning of the State of Alagoas and through surveys of own classification of companies in the sugar and alcohol sector that have identification of areas of occurrence. They were submitted to chemical and physical analysis, by direct methods (aggregate stability and erodibility determination) and indirect (simulated rain) through mathematical models. The soil erodibility factor in interfurrows presented values that varied from 6.01 x 10-6 Kg s-1 m-4 for Yellow Latosol, to 16.65 x 10-6 Kg s-1 m-4 for Red-Yellow Latosol. This variation was also significant within the suborders, with more homogeneous values observed in the Red Latosols suborder. Thus, it is concluded that for the soil erodibility factor for Latosols, it is recommended to use the simulated rainfall methodology, in field or laboratory conditions through the Water Erosion Prediction Project model.

Preparation of Acetylenediol (HOCCOH) and Glyoxal (HCOCHO) in Interstellar Analog Ices of Carbon Monoxide and Water

Enols—tautomers of ketones or aldehydes—are considered key intermediates in the formation of prebiotic sugars and sugar acids. Although laboratory simulation experiments suggest that enols should be ubiquitous in the interstellar medium, the underlying formation mechanisms of enols in interstellar environments are largely elusive. Here, we present the laboratory experiments on the formation of glyoxal (HCOCHO) along with its ynol tautomer acetylenediol (HOCCOH) in interstellar ice analogs composed of carbon monoxide (CO) and water (H2O) upon exposure to energetic electrons as a proxy for secondary electrons generated from Galactic cosmic rays. Utilizing tunable vacuum ultraviolet photoionization reflectron time-of-flight mass spectrometry, glyoxal and acetylenediol were detected in the gas phase during temperature-programmed desorption. Our results reveal the formation pathways of glyoxal via radical–radical recombination of two formyl (HĊO) radicals, and that of acetylenediol via keto-enol-ynol tautomerization. Due to the abundance of carbon monoxide and water in interstellar ices, glyoxal and acetylenediol are suitable candidates for future astronomical searches. Furthermore, the detection of acetylenediol in astrophysically relevant ices advances our understanding for the formation pathways of high-energy tautomers such as enols in deep space.

Study on mechanism of particle aggregation and pore formation during loess air-fall deposition based on discrete element method

The pore structure of aeolian deposits is essential for predicting their mechanical properties and the climatic conditions during their deposition. The discrete element method (DEM) is a practical approach for analysing the formation and evolution mechanisms of aeolian deposits’ pore structure. However, the effect of particle shape and non-contact van der Waals force on deposits’ pore structure with different particle sizes needs further exploration to enhance the efficiency and accuracy of DEM simulations. We developed a VdwForce model for DEM that accounts for the van der Waals force’s long-tail effect, and we conducted loess air-fall numerical tests that matched laboratory simulation tests. DEM simulations and laboratory tests show that the deposits’ porosity increased as the median particle size decreased, whether using spherical or actual shape particles in simulations. When deposits formed by particles with actual shapes have dense packing structures, simulations utilising spherical particles of the same size produce larger porosities. The primary reason of the alteration in the pore structure of the loess air-fall deposits is the shift in the quantity and pattern of particle agglomerates caused by van der Waals attractive force. So, the aggregation process during air-fall was essential for forming overhead pore structures.

How a project design becomes a macro-actor: laboratory simulations in trials of strength between competing bridge designs, project budgets and sustainability

PurposeThis paper shows how Bruno Latour’s novel work and methodological approach can enrich management and organization studies, accounting and science and technology studies on what it takes to redesign sustainable societal infrastructures. Latour’s notions of trials of strength, macro-actor and design as redesign are used in a case study to describe and analyse how the laboratory becomes decisive in negotiating the bridge design and project budget to the benefit of a more sustainable transport infrastructure.Design/methodology/approachLatour’s notion of the detective-author is used to research and write a longitudinal qualitative case study that reconstructs the project processes and chain of related events by following the actors/actants.FindingsThe case analysis shows how a project design becomes an emerging powerful macro-actor through the mobilization of laboratory simulations and calculations. The role of the project budget changes; from a strong supporting role as input to a decision option in favour of a cheaper stayed bridge to a weak role as an output from a process of redesign supporting a much larger, costlier and more sustainable suspension bridge.Originality/valueWe use Latour’s methodological approach to engage primarily in detailed process descriptions to go beyond the often-pointless call for further theory development and to rather account for what is at work in specific situations. Latour’s notions of redesign as an outcome from trials of strength, we consider a useful approach to further our understanding since it also takes account of the distributed knowledge production that is integral to the actors’ cognitions and recognitions. Relatedly, the specific Latourian notion of redesign opens up new avenues for researching the more or less powerful role accounting devices such as a project budget can play in valuing, supporting and/or undermining the design of sustainable societal infrastructures.

Antifungal Potential of Secondary Metabolites Derived from Arcangelisia flava (L.) Merr.: An Analysis of In Silico Enzymatic Inhibition and In Vitro Efficacy against Candida Species

Considering the escalating resistance to conventional antifungal medications, it is critical to identify novel compounds that can efficiently counteract this challenge. The purpose of this research was to elucidate the fungicidal properties of secondary metabolites derived from Arcangelisia flava, with a specific focus on their efficacy against Candida species. This study utilized a combination approach comprising laboratory simulations and experiments to discern and evaluate the biologically active constituents present in the dichloromethane extract of A. flava. The in vitro experiments demonstrated that compounds 1 (palmatine) and 2 (fibraurin) exhibited antifungal properties. The compounds exhibited minimum inhibitory concentrations (MICs) ranging from 15.62 to 62.5 µg/mL against Candida sp. Moreover, compound 1 demonstrated a minimum fungicidal concentration (MFC) of 62.5 µg/mL against Candida glabrata and C. krusei. In contrast, compound 2 exhibited an MFC of 125 µg/mL against both Candida species. Based on a molecular docking study, it was shown that compounds 1 and 2 have a binding free energy of −6.6377 and −6.7075 kcal/mol, respectively, which indicates a strong affinity and specificity for fungal enzymatic targets. This study utilized pharmacophore modeling and Density Functional Theory (DFT) simulations to better understand the interaction dynamics and structural properties crucial for antifungal activity. The findings underscore the potential of secondary metabolites derived from A. flava to act as a foundation for creating novel and highly efficient antifungal treatments, specifically targeting fungal diseases resistant to existing treatment methods. Thus, the results regarding these compounds can provide references for the next stage in antifungal drug design. Further investigation is necessary to thoroughly evaluate these natural substances’ clinical feasibility and safety characteristics, which show great potential as antifungal agents.

Reducing Soil-Emitted Nitrous Acid as a Feasible Strategy for Tackling Ozone Pollution.

Severe ozone (O3) pollution has been a major air quality issue and affects environmental sustainability in China. Conventional mitigation strategies focusing on reducing volatile organic compounds and nitrogen oxides (NOx) remain complex and challenging. Here, through field flux measurements and laboratory simulations, we observe substantial nitrous acid (HONO) emissions (FHONO) enhanced by nitrogen fertilizer application at an agricultural site. The observed FHONO significantly improves model performance in predicting atmospheric HONO and leads to regional O3 increases by 37%. We also demonstrate the significant potential of nitrification inhibitors in reducing emissions of reactive nitrogen, including HONO and NOx, by as much as 90%, as well as greenhouse gases like nitrous oxide by up to 60%. Our findings introduce a feasible concept for mitigating O3 pollution: reducing soil HONO emissions. Hence, this study has important implications for policy decisions related to the control of O3 pollution and climate change.

Towards the Optimization of a Photovoltaic/Membrane Distillation System for the Production of Pure Water.

The production of pure water plays a pivotal role in enabling sustainable green hydrogen production through electrolysis. The current industrial approach for generating pure water relies on energy-intensive techniques such as reverse osmosis. This study unveils a straightforward method to produce pure water, employing real-world units derived from previously simulated and developed laboratory devices. This demonstrated system is cost-effective and boasts low energy consumption, utilizing membrane distillation (MD) driven by the waste heat harnessed from photovoltaic (PV) panels. In a previous study, modeling simulations were conducted to optimize the multi-layered MD system, serving as a blueprint for the construction of prototype devices with a suitable selection of materials, enabling the construction of field-testable units. The most efficient PV-MD device, featuring evaporation and condensation zones constructed from steel sheets and polytetrafluoroethylene (PTFE) membranes, is capable of yielding high-purity water with conductivity levels below 145 μS with high flux rates.

Laboratory characterization of hydrothermally processed oligopeptides in ice grains emitted by Enceladus and Europa.

The Cassini mission provided evidence for a global subsurface ocean and ongoing hydrothermal activity on Enceladus, based on results from Cassini's mass spectrometers. Laboratory simulations of hydrothermal conditions on icy moons are needed to further constrain the composition of ejected ice grains containing hydrothermally altered organic material. Here, we present results from our newly established facility to simulate the processing of ocean material within the temperature range 80-150°C and the pressure range 80-130 bar, representing conditions suggested for the water-rock interface on Enceladus. With this new facility, we investigate the hydrothermal processing of triglycine (GGG) peptide and, for the first time, analyse the extracted samples using laser-induced liquid beam ion desorption (LILBID) mass spectrometry, a laboratory analogue for impact ionization mass spectrometry of ice grains in space. We outline an approach to elucidate hydrothermally processed GGG in ice grains ejected from icy moons based on characteristic differences between GGG anion and cation mass spectra. These differences are linked to hydrothermal processing and thus provide a fingerprint of hydrothermal activity on extraterrestrial bodies. These results will serve as important guidelines for biosignatures potentially obtained by a future Enceladus mission and the SUrface Dust Analyzer (SUDA) instrument onboard Europa Clipper. This article is part of the theme issue 'Dust in the Solar System and beyond'.

The effect of aquathermolysis catalyst on the processing of Yarega oil

This study focuses on the synthesis of oil-soluble precursor catalysts using iron and nickel and evaluates their performance through laboratory simulations of aquathermolysis processes under varying temperature and duration conditions. The investigation highlights that the initial oil sample exhibits high resin content (27 %) and asphaltenes (∼4 %). Gas phase analysis reveals a significant increase in the levels of n-C1-C5 hydrocarbons and C4–C10 isomers (up to 3.5–4 times compared to control experiments), indicating substantial alterations in the oil's composition. After thermal steam treatment (TST), the viscosity of all samples decreases in comparison to the initial oil. For instance, when using an iron talate catalyst, the viscosity drops to 575 mPa s, which is approximately 10.5 times lower than the initial oil viscosity of 6027 mPa s. Additionally, experiments involving iron-based catalysts consistently exhibit reduced viscosity compared to control experiments, achieving a 2.2-fold decrease after a 72-h duration (from 1928 mPa s to 743 mPa s).Economic evaluations were conducted, demonstrating an additional oil production increase of 2855 tons. The net discounted income over a span of 4 years, resulting from the application of this catalytic aquathermolysis technology, totaled 40,652,750 russian rubles.

Assessment of the Midwifery Education Program at the University of British Columbia – A Survey of Graduates and Midwife Mentors

The Midwifery Program at the University of British Columbia is the only academic centre for midwifery education in British Columbia. The program consists of arts and science courses, midwifery theoretical and clinical courses, problem-based learning tutorials, laboratory simulations, clinical experiences in community midwifery, and a semester of interprofessional placements in a local or global setting. As university based midwifery education is new to British Columbia, critical evaluation of the curriculum is essential. Between 2005 and 2010, we examined the curriculum annually from the perspective of new graduates (n=34) and their mentors (n=21) to inform curriculum renewal and development. Overall graduates felt well prepared for clinical practice after graduating, and highly valued their clinical placements. Both graduates and midwife mentors reported competence with most clinical skills, and senior midwives noted the graduates’ fluency with both the hospital and home setting. Need for improvement was noted with respect to suturing and venipuncture. There were some discrepancies in the assessment of competencies. While all graduates felt well or adequately prepared to recognize and manage when a normal birth changes to abnormal, not all mentor midwives agreed. Conversely, midwife mentors felt that graduates were prepared in the area of client communication and counseling, yet graduates felt less confident in this area. Over the years, the Midwifery Education curriculum has evolved to address feedback received via the yearly curriculum evaluation. The academic calendar has been modified to allow students and faculty more time for preparation, integration and reflection during the introductory year, to facilitate the consolidation phase in the core clinical courses, and to facilitate senior research projects. Courses on counseling, pharmacology for midwives, lactation consultation, global maternity care, and anatomy labs have been added to the curriculum. The program continues its effort to enhance theoretical and clinical teaching by offering regular preceptor workshops.