bluuebunny/crossref_metadata_2025 huggingface dataset:
Practical Prediction of the Boil-Off Rate of Independent-Type Storage Tanks
Authors: Lee Dong-Ha , Cha Seung-Joo , Kim Jeong-Dae , Kim Jeong-Hyeon , Kim Seul-Kee , Lee Jae-Myung
Published: January 2021

Because environmentally-friendly fuels such as natural gas and hydrogen are primarily stored in the form of cryogenic liquids to enable efficient transportation, the demand for cryogenic fuel (LNG, LH) ships has been increasing as the primary carriers of environmentally-friendly fuels. In such ships, insulation systems must be used to prevent heat inflow to the tank to suppress the generation of boil-off gas (BOG). The presence of BOG can lead to an increased internal pressure, and thus, its control and prediction are key aspects in the design of fuel tanks. In this regard, although the thermal analysis of the phase change through a finite element analysis requires less computational time than that implemented through computational fluid dynamics, the former is relatively more error-prone. Therefore, in this study, a cryogenic fuel tank to be incorporated in ships was established, and the boil-off rate (BOR), measured considering liquid nitrogen, was compared with that obtained using the finite element method. Insulation material with a cubic structure was applied to the cylindrical tank to increase the insulation performance and space efficiency. To predict the BOR through finite element analysis, the effective thermal conductivity was calculated through an empirical correlation and applied to the designed fuel tank. The calculation was predicted to within 1% of the minimum error, and the internal fluid behavior was evaluated by analyzing the vertical temperature profile according to the filling ratio.
Observed Changes of a Mega Feeder Nourishment in a Coastal Cell: Five Years of Sand Engine Morphodynamics
Authors: Roest Bart , de Vries Sierd , de Schipper Matthieu , Aarninkhof Stefan
Published: January 2021

Recently, mega feeder nourishments have been proposed as a new strategy to nourish sediment-starving beaches. This strategy involves the placement of a large, concentrated sediment volume at a single location along the coast. Wind, waves and currents act as the natural agents to spread the sediment alongshore over the course of years to decades. This article presents the morphological development of the first full-scale implementation of this strategy, examining the 20 × 106 m3“Sand Engine” feeder nourishment and its impact on adjacent coastal sections. The analysis is based on 37 high-resolution topographical surveys, executed in a 17 km coastal cell. These unique data describe the alongshore spreading in the first five years and the response at different elevations of the coastal profile. The analysis shows rapid transformation of the nourishment’s planform shape, changing rapidly into a smooth (Gaussian-like) shape which is gradually extending alongshore over time. Within five years, sediment has been distributed to a 5.8 km stretch of coast from the initial 2.2 km peninsula footprint. Changes in cross-shore and alongshore extent varied strongly over depth, with the strongest morphological response at the mean sea level (MSL) isobath and limited morphodynamic activity at deeper water, below −8 m MSL. This depth-dependent response has resulted in decreasing subtidal slopes in eroding areas, accretive areas contrastingly show a slope increment. These results yield important insights in nourished sediment mobility at different depths near the coast and distribution over a larger coastal cell. However, this single-design assessment cannot address the wide range of mega nourishment design parameters essential for morphological development of its coastal cell. This work suggests limiting cross-shore extent, since it is uncertain whether nourished sediment at deeper water will become active in the coastal system. A continuation of the current monitoring and future research might shed more light on this.
Interacting with Hemoglobin: Paracoccidioides spp. Recruits hsp30 on Its Cell Surface for Enhanced Ability to Use This Iron Source
Authors: de Souza Aparecido Ferreira , Tomazett Mariana Vieira , Freitas e Silva Kleber Santiago , de Curcio Juliana Santana , Pereira Christie Ataides , Baeza Lilian Cristiane , Paccez Juliano Domiraci , Gonçales Relber Aguiar , Rodrigues Fernando , Pereira Maristela , de Almeida Soares Célia Maria
Published: January 2021

Paracoccidioides spp. are thermally dimorphic fungi that cause paracoccidioidomycosis and can affect both immunocompetent and immunocompromised individuals. The infection can lead to moderate or severe illness and death. Paracoccidioides spp. undergo micronutrients deprivation within the host, including iron. To overcome such cellular stress, this genus of fungi responds in multiple ways, such as the utilization of hemoglobin. A glycosylphosphatidylinositol (GPI)-anchored fungal receptor, Rbt5, has the primary role of acquiring the essential nutrient iron from hemoglobin. Conversely, it is not clear if additional proteins participate in the process of using hemoglobin by the fungus. Therefore, in order to investigate changes in the proteomic level of P. lutzii cell wall, we deprived the fungus of iron and then treated those cells with hemoglobin. Deprived iron cells were used as control. Next, we performed cell wall fractionation and the obtained proteins were submitted to nanoUPLC-MSE. Protein expression levels of the cell wall F1 fraction of cells exposed to hemoglobin were compared with the protein expression of the cell wall F1 fraction of iron-deprived cells. Our results showed that P. lutzii exposure to hemoglobin increased the level of adhesins expression by the fungus, according to the proteomic data. We confirmed that the exposure of the fungus to hemoglobin increased its ability to adhere to macrophages by flow cytometry. In addition, we found that HSP30 of P. lutzii is a novel hemoglobin-binding protein and a possible heme oxygenase. In order to investigate the importance of HSP30 in the Paracoccidioides genus, we developed a Paracoccidioides brasiliensis knockdown strain of HSP30 via Agrobacterium tumefaciens-mediated transformation and demonstrated that silencing this gene decreases the ability of P. brasiliensis to use hemoglobin as a nutrient source. Additional studies are needed to establish HSP30 as a virulence factor, which can support the development of new therapeutic and/or diagnostic approaches.
Italexit and the Impact of Immigrants from Italy on the Italian Labor Market
Authors: Simionescu Mihaela
Published: January 2021

Considering the recent debates regarding Brexit and the potential negative effects of immigrants on Italian labor market, the main aim of this paper is to assess the impact of immigrants from Italy on the labor market of this country using econometric techniques. Based on these results, one answer regarding the potential exit of Italy from the EU (Italexit) because of the immigration issue is provided. According to a Johansen co-integration test, there was not any long-run relationship between the number of EU immigrants from Italy and the variation of unemployment rate in the period from 1990 to 2019. The estimations based on Bayesian ridge regressions indicated that the number of EU immigrants did not affect labor cost index in business economy, manufacturing or industry, construction and services in the period 2001–2019. The variation in employed immigrants from Italy in the period 2008–2019 depends on changes in risk of poverty or social exclusion, housing cost overburden rate, exports of goods and services, inflation and tax rate on low wage earners and adult participation in learning.
Infrastructural and Social Aspects of ICT Dissemination in Rural Areas in Ukraine in Juxtaposition with Other Post-Transition Countries—State of Play and Prospects for Rural Development
Authors: Synowiec Aleksandra
Published: January 2021

The objective of this study is to identify the current state of, and the prospects for, information and communication technologies (ICT) dissemination in rural areas in Ukraine in juxtaposition with other post-transition countries. The spread of ICT is discussed within the frame of economic, infrastructural, and social factors affecting rural areas in Ukraine since the post-communist transition period. Information and communication technologies may support the socio-economic development of peripheral areas in many ways—including rural ones. Dissemination of ICT contributes to the emergence of sources of income, equalizes education opportunities, and increases the attractiveness of rural areas. However, the rural—urban divide in the countries of Central and Eastern Europe and other former USSR countries is still remarkable and, as a type of structural inequality, should be better recognized. The source material is based on secondary data, which consists of selected literature on the subject of rural development in Central and Eastern European Countries, strategic documents, available reports and studies of international institutions, research from agencies, state documents and statistics, and research conducted by international and domestic NGOs. In reference to the paper’s objective, the method of content analysis was employed. Dissemination of ICT in rural areas in Ukraine is influenced by two groups of factors. The infrastructural divide concerning Internet access between rural and urban populations in Ukraine has been diminishing, but the issue of structural exclusion due to place of residence has still not been solved. As far as the social aspects of ICT dissemination in rural areas in Ukraine are concerned, the level of digital literacy among rural dwellers is significantly lower in comparison to urban residents. Rural areas are more exposed to the consequences of various aspects of digital exclusion.
Monitoring Invasive Plant Species Using Hyperspectral Remote Sensing Data
Authors: Papp Levente , van Leeuwen Boudewijn , Szilassi Péter , Tobak Zalán , Szatmári József , Árvai Mátyás , Mészáros János , Pásztor László
Published: January 2021

The species richness and biodiversity of vegetation in Hungary are increasingly threatened by invasive plant species brought in from other continents and foreign ecosystems. These invasive plant species have spread aggressively in the natural and semi-natural habitats of Europe. Common milkweed (Asclepias syriaca) is one of the species that pose the greatest ecological menace. Therefore, the primary purpose of the present study is to map and monitor the spread of common milkweed, the most common invasive plant species in Europe. Furthermore, the possibilities to detect and validate this special invasive plant by analyzing hyperspectral remote sensing data were investigated. In combination with field reference data, high-resolution hyperspectral aerial images acquired by an unmanned aerial vehicle (UAV) platform in 138 spectral bands in areas infected by common milkweed were examined. Then, support vector machine (SVM) and artificial neural network (ANN) classification algorithms were applied to the highly accurate field reference data. As a result, common milkweed individuals were distinguished in hyperspectral images, achieving an overall accuracy of 92.95% in the case of supervised SVM classification. Using the ANN model, an overall accuracy of 99.61% was achieved. To evaluate the proposed approach, two experimental tests were conducted, and in both cases, we managed to distinguish the individual specimens within the large variety of spreading invasive species in a study area of 2 ha, based on centimeter spatial resolution hyperspectral UAV imagery.
Soil Degradation and Socioeconomic Systems’ Complexity: Uncovering the Latent Nexus
Authors: Gambella Filippo , Quaranta Giovanni , Morrow Nathan , Vcelakova Renata , Salvati Luca , Gimenez Morera Antonio , Rodrigo-Comino Jesús
Published: January 2021

Understanding Soil Degradation Processes (SDPs) is a fundamental issue for humankind. Soil degradation involves complex processes that are influenced by a multifaceted ensemble of socioeconomic and ecological factors at vastly different spatial scales. Desertification risk (the ultimate outcome of soil degradation, seen as an irreversible process of natural resource destruction) and socioeconomic trends have been recently analyzed assuming “resilience thinking” as an appropriate interpretative paradigm. In a purely socioeconomic dimension, resilience is defined as the ability of a local system to react to external signals and to promote future development. This ability is intrinsically bonded with the socio-ecological dynamics characteristic of environmentally homogeneous districts. However, an evaluation of the relationship between SDPs and socioeconomic resilience in local systems is missing in mainstream literature. Our commentary formulates an exploratory framework for the assessment of soil degradation, intended as a dynamic process of natural resource depletion, and the level of socioeconomic resilience in local systems. Such a framework is intended to provide a suitable background to sustainability science and regional policies at the base of truly resilient local systems.
Quantifying the Land Use and Land Cover Changes in the Yellow River Basin while Accounting for Data Errors Based on GlobeLand30 Maps
Authors: Sun Xiaofang , Li Guicai , Wang Junbang , Wang Meng
Published: January 2021

Land use and land cover (LULC) change influences many issues such as the climate, ecological environment, and economy. In this study, the LULC transitions in the Yellow River Basin (YRB) were analyzed based on the GlobeLand30 land use data in 2000, 2010, and 2020. The intensity analysis method with hypothetical errors calculation was used, which could explain the deviations from uniform land changes. The strength of the evidence for the deviation was revealed even though the confusion matrixes of the LULC data at each time point for the YRB were unavailable. The results showed that at the interval scale, the land transition rate increased from the first to the second period for all of the upper, middle, and lower reaches. The exchange component was larger than the quantity and shift component, and the gross change was 4.1 times larger than the net change. The size of cultivated land decreased during both intervals. The artificial surfaces gains were active for all three reaches and had strong evidence. A hypothetical error in 93% of the 2000 data and 58% of the 2010 data can explain deviations from uniform transition given woodland gain during 2000–2010 and 2010–2020. Ecological restoration projects such as Grain for Green implemented in 2000 in the upper reaches resulted in the woodland increase.
A Review on AA 6061 Metal Matrix Composites Produced by Stir Casting
Authors: Kareem Ansar , Qudeiri Jaber Abu , Abdudeen Asarudheen , Ahammed Thanveer , Ziout Aiman
Published: January 2021

In recent years, many alloys as well as composites of aluminium were developed for enhanced material performance. AA 6061 is an aluminium alloy that has extensive applications due to its superior material characteristics. It is a popular choice of matrix for aluminium matrix composite (AMC) fabrication. This study provides a review on AA 6061 aluminium alloy matrix composites produced through the stir-casting process. It focusses on conventional stir-casting fabrication, process parameters, various reinforcements used, and the mechanical properties of the AA 6061 composites. Several research studies indicated that the stir-casting method is widely used and suitable for fabricating AA 6061 composites with reinforcements such as SiC, B4C, Al2O3, TiC, as well as other inorganic, organic, hybrid, and nanomaterials. The majority of the studies showed that an increase in the reinforcement content enhanced the mechanical and tribological properties of the composites. Furthermore, hybrid composites showed better material properties than single reinforcement composites. The usage of industrial and agricultural residues in hybrid composites is also reported. Future studies could focus on the fabrication of AA 6061 nanocomposites through stir casting and their material characterisation, since they have great potential as advanced materials.
Fatigue Crack Growth and Fracture of Internal Fixation Materials in In Vivo Environments—A Review
Authors: Wu Kailun , Li Bin , Guo Jiong
Published: January 2021

The development of crack patterns is a serious problem affecting the durability of orthopedic implants and the prognosis of patients. This issue has gained considerable attention in the medical community in recent years. This literature focuses on the five primary aspects relevant to the evaluation of the surface cracking patterns, i.e., inappropriate use, design flaws, inconsistent elastic modulus, allergic reaction, poor compatibility, and anti-corrosiveness. The hope is that increased understanding will open doors to optimize fabrication for biomedical applications. The latest technological issues and potential capabilities of implants that combine absorbable materials and shape memory alloys are also discussed. This article will act as a roadmap to be employed in the realm of orthopedic. Fatigue crack growth and the challenges associated with materials must be recognized to help make new implant technologies viable for wider clinical adoption. This review presents a summary of recent findings on the fatigue mechanisms and fracture of implant in the initial period after surgery. We propose solutions to common problems. The recognition of essential complications and technical problems related to various approaches and material choices while satisfying clinical requirements is crucial. Additional investigation will be needed to surmount these challenges and reduce the likelihood of fatigue crack growth after implantation.
The Bad and the Good—Microorganisms in Cultural Heritage Environments—An Update on Biodeterioration and Biotreatment Approaches
Authors: Pyzik Adam , Ciuchcinski Karol , Dziurzynski Mikolaj , Dziewit Lukasz
Published: January 2021

Cultural heritage objects constitute a very diverse environment, inhabited by various bacteria and fungi. The impact of these microorganisms on the degradation of artworks is undeniable, but at the same time, some of them may be applied for the efficient biotreatment of cultural heritage assets. Interventions with microorganisms have been proven to be useful in restoration of artworks, when classical chemical and mechanical methods fail or produce poor or short-term effects. The path to understanding the impact of microbes on historical objects relies mostly on multidisciplinary approaches, combining novel meta-omic technologies with classical cultivation experiments, and physico-chemical characterization of artworks. In particular, the development of metabolomic- and metatranscriptomic-based analyses associated with metagenomic studies may significantly increase our understanding of the microbial processes occurring on different materials and under various environmental conditions. Moreover, the progress in environmental microbiology and biotechnology may enable more effective application of microorganisms in the biotreatment of historical objects, creating an alternative to highly invasive chemical and mechanical methods.
CAD-Based 3D-FE Modelling of AISI-D3 Turning with Ceramic Tooling
Authors: Kyratsis Panagiotis , Tzotzis Anastasios , Markopoulos Angelos , Tapoglou Nikolaos
Published: January 2021

In this study, the development of a 3D Finite Element (FE) model for the turning of AISI-D3 with ceramic tooling is presented, with respect to four levels of cutting speed, feed, and depth of cut. The Taguchi method was employed in order to create the orthogonal array according to the variables involved in the study, reducing this way the number of the required simulation runs. Moreover, the possibility of developing a prediction model based on well-established statistical tools such as the Response Surface Methodology (RSM) and the Analysis of Variance (ANOVA) was examined, in order to further investigate the relationship between the cutting speed, feed, and depth of cut, as well as their influence on the produced force components. The findings of this study point out an increased correlation between the experimental results and the simulated ones, with a relative error below 10% for most tests. Similarly, the values derived from the developed statistical model indicate a strong agreement with the equivalent numerical values due to the verified adequacy of the statistical model.
The Microstructural Model of the Ferromagnetic Material Behavior in an External Magnetic Field
Authors: Rogovoy Anatoli A. , Stolbov Oleg V. , Stolbova Olga S.
Published: January 2021

In this paper, the behavior of a ferromagnetic material is considered in the framework of microstructural modeling. The equations describing the behavior of such material in the magnetic field, are constructed based on minimization of total magnetic energy with account of limitations imposed on the spontaneous magnetization vector and scalar magnetic potential. This conditional extremum problem is reduced to the unconditional extremum problem using the Lagrange multiplier. A variational (weak) formulation is written down and linearization of the obtained equations is carried out. Based on the derived relations a solution of a two-dimensional problem of magnetization of a unit cell (a grain of a polycrystal or a single crystal of a ferromagnetic material) is developed using the finite element method. The appearance of domain walls is demonstrated, their thickness is determined, and the history of their movement and collision is described. The graphs of distributions of the magnetization vector in domains and in domain walls in the external magnetic field directed at different angles to the anisotropy axis are constructed and the magnetization curves for a macrospecimen are plotted. The results obtained in the present paper (the thickness of the domain wall, the formation of a 360-degree wall) are in agreement with the ones available in the current literature.
A Picard-Type Iterative Scheme for Fredholm Integral Equations of the Second Kind
Authors: Gutiérrez José M. , Hernández-Verón Miguel Á.
Published: January 2021

In this work, we present an application of Newton’s method for solving nonlinear equations in Banach spaces to a particular problem: the approximation of the inverse operators that appear in the solution of Fredholm integral equations. Therefore, we construct an iterative method with quadratic convergence that does not use either derivatives or inverse operators. Consequently, this new procedure is especially useful for solving non-homogeneous Fredholm integral equations of the first kind. We combine this method with a technique to find the solution of Fredholm integral equations with separable kernels to obtain a procedure that allows us to approach the solution when the kernel is non-separable.
The Relationship between PID-5 Personality Traits and Mental States. A Study on a Group of Young Adults at Risk of Psychotic Onset
Authors: Meliante Maria , Rossi Chiara , Malvini Lara , Niccoli Clara , Oasi Osmano , Barbera Simona , Percudani Mauro
Published: January 2021

Background and Objectives: The diagnosis of psychosis is a challenge for the scientific community, both in terms of its definition and treatment. Some recent studies have investigated the relationship between personality and psychosis onset to prevent or intervene early. Materials and Methods: Sixty young adults were recruited during their first access in 2019 near the Community Mental Health Service of Niguarda Hospital, Milan, Italy. The assessment included the Social and Occupational Functioning Assessment Scale (SOFAS), the Global Assessment of Functioning (GAF) (clinician scales), the 16-item Version of the Prodromal Questionnaire (PQ-16), the Personality Inventory for DSM-5 (PID-5) (self-report), and a clinical session. Statistical analysis was performed by SPSS. Results: The results show a negative correlation between the Detachment domain and the GAF scores. Correlational analysis also highlights that all PID-5 domains, except for Antagonism, have positive correlations with high scores in the PQ-16. The multivariate analysis of variance showed that patients diagnosed with versus without a psychotic disorder significantly differed on Detachment, Antagonism and Psychoticism PID-5 domains. Conclusions: The involvement of the personality construct in psychopathological development is displayed. In particular, higher levels of Detachment and Psychoticism can distinguish people who are more vulnerable to psychosis or who already have overt psychosis from those who do not have a psychotic predisposition. The study highlights the fundamental role of personality traits, emerging from PID-5, to distinguish young adults at risk of onset.
Power Generation Performance of a Pilot-Scale Reverse Electrodialysis Using Monovalent Selective Ion-Exchange Membranes
Authors: Mehdizadeh Soroush , Kakihana Yuriko , Abo Takakazu , Yuan Qingchun , Higa Mitsuru
Published: January 2021

Reverse electrodialysis (RED) is a promising process for harvesting energy from the salinity gradient between two solutions without environmental impacts. Seawater (SW) and river water (RW) are considered the main RED feed solutions because of their good availability. In Okinawa Island (Japan), SW desalination via the reverse osmosis (RO) can be integrated with the RED process due to the production of a large amount of RO brine (concentrated SW, containing ~1 mol/dm3 of NaCl), which is usually discharged directly into the sea. In this study, a pilot-scale RED stack, with 299 cell pairs and 179.4 m2 of effective membrane area, was installed in the SW desalination plant. For the first time, asymmetric monovalent selective membranes with monovalent selective layer just at the side of the membranes were used as the ion exchange membranes (IEMs) inside the RED stack. Natural and model RO brines, as well as SW, were used as the high-concentrate feed solutions. RW, which was in fact surface water in this study and close to the desalination plant, was utilized as the low-concentrate feed solution. The power generation performance investigated by the current-voltage (I–V) test showed the maximum gross power density of 0.96 and 1.46 W/m2 respectively, when the natural and model RO brine/RW were used. These are a 50–60% improvement of the maximum gross power of 0.62 and 0.97 W/m2 generated from the natural and model SW, respectively. The approximate 50% more power generated from the model feed solutions can be assigned to the suppression of concentration polarization of the RED stack due to the absence of multivalent ions.
Quantifying Charge Effects on Fouling Layer Strength and (Ir)Removability during Cross-Flow Microfiltration
Authors: Jørgensen Mads Koustrup , Mattsson Tuve
Published: January 2021

Fouling of membranes is still an important limiting factor in the application of membrane technology. Therefore, there is still a need for an in-depth understanding of which parameters affect the (ir)removability of fouling layers, as well as the mechanisms behind fouling. In this study, fluid dynamic gauging (FDG) was used to investigate the influence of charge effects between negatively charged foulant particles and cations on cake cohesive strength. Fouling cakes’ thicknesses and cohesive strengths were estimated during membrane operations, where microfiltration (MF) membranes were fouled in a feed-and-bleed cross-flow filtration system with low and highly negatively charged polystyrene–polyacrylic acid core-shell particles. In addition, an added procedure to determine the irremovability of cakes using FDG was also proposed. Comparing layers formed in the presence and absence of calcium ions revealed that layers formed without calcium ions had significantly lower cohesive strength than layers formed in the presence of calcium ions, which is explained by the bridging effect between negatively charged particles and calcium ions. Results also confirmed more cohesive cakes formed by high negative charge particles in the presence of calcium compared to lower negative charge particles. Hence, it was demonstrated that FDG can be used to assess the cohesive strength ((ir)removability) of cake layers, and to study how cake cohesive strength depends on foulant surface charge and ionic composition of the solution.
On the Effect of Multiple Passes on Kerf Characteristics and Efficiency of Abrasive Waterjet Cutting
Authors: Karmiris-Obratański Panagiotis , Karkalos Nikolaos E. , Kudelski Rafał , Papazoglou Emmanouil L. , Markopoulos Angelos P.
Published: January 2021

Abrasive waterjet cutting is a well-established non-conventional technique for the processing of difficult-to-cut material and rendering of various complex geometries with high accuracy. However, as in every machining process, it is also required that high efficiency and productivity are achieved. For that reason, in the present study, the effect of performing the machining process by multiple passes is investigated, and the evaluation of this approach is performed in terms of total depth of penetration, kerf width, kerf taper angle, mean material removal rate, and cutting efficiency. In the case of multiple passes, the passes are performed in the same direction with the traverse speed adjusted accordingly in order to maintain the total machining time constant in each case. From the experimental results, it was found that the effect of multiple passes on the kerf characteristics, mean material removal rate, and cutting efficiency depends on the process conditions, especially regarding the depth of penetration, and it is possible to achieve significantly higher efficiency by the multi-pass cutting technique when the appropriate process conditions are selected.
Advanced Structural Materials for Gas-Cooled Fast Reactors—A Review
Authors: Čížek Jakub , Kalivodová Jana , Janeček Miloš , Stráský Josef , Srba Ondřej , Macková Anna
Published: January 2021

This review summarizes the development of the Gas-Cooled Fast Reactor (GFR) concept from the early 1970s until now, focusing specifically on structural materials and advanced fuel cladding materials. Materials for future nuclear energy systems must operate under more extreme conditions than those in the current Gen II or Gen III systems. These conditions include higher temperatures, a higher displacement per atom, and more corrosive environments. This paper reviews previous GFR concepts in light of several promising candidate materials for the GFR system. It also reviews the recent development of nuclear power and its use in the peaceful exploration of space. The final section focuses on the development and testing of new advanced materials such as SiCf/SiC composites and high entropy alloys (HEA) for the construction and development of GFRs.
On the CFD Modelling of Slamming of the Metal Melt in High-Pressure Die Casting Involving Lost Cores
Authors: Kohlstädt Sebastian , Vynnycky Michael , Goeke Stephan
Published: January 2021

This paper uses computational fluid dynamics (CFD), in the form of the OpenFOAM software package, to investigate the forces on the salt core in high-pressure die casting (HPDC) when being exposed to the impact of the inflowing melt in the die filling stage, with particular respect to the moment of first impact—commonly known as slamming. The melt-air system is modelled via an Eulerian volume-of-fluid approach, treating the air as a compressible perfect gas. The turbulence is treated via a Reynolds-averaged Navier Stokes (RANS) approach. The RNG k-ε and the Menter SST k-ω models are both evaluated, with the use of the latter ultimately being adopted for batch computations. A study of the effect of the Courant number, with a view to establishing mesh independence, indicates that meshes which are finer, and time steps that are smaller, than those previously employed for HPDC simulations are required to capture the effect of slamming on the core properly, with respect to existing analytical models and empirical measurements. As a second step, it is then discussed what response should be expected when this force, with its spike-like morphology and small force-time integral, impacts the core. It is found that the displacement of the core due to the spike in the force is so small that, even though the force is high in value, the bending stress inside the core remains below the critical limit for fracture. It can therefore be concluded that, when assuming homogeneous crack-free material conditions, the spike in the force is not failure-critical.
Application of P(VDF-TrFE) Glass Coating for Robust Harmonic Nanoparticles Characterization
Authors: Ilchenko Svitlana G. , Multian Volodymyr V. , Lymarenko Ruslan A. , Taranenko Victor B. , Pullano Salvatore A. , Fiorillo Antonino S. , Gayvoronsky Volodymyr Ya.
Published: January 2021

Polyvinylidene fluoride and its copolymers are a well-known family of low-cost ferroelectric materials widely used for the fabrication of devices for a wide range of applications. A biocompatibility, high optical quality, chemical and mechanical durability of poly(vinylidene fluoride–trifluoroethylene), (P(VDF–TrFE)), makes it particularly attractive for designing of effective coating layers for different diagnostic techniques. In the present work, the nonlinear optical characterization of P(VDF-TrFE)-coating films deposited onto a glass substrate was done. Advantages of the coating application for cells/substrates in the field of multiphoton imaging the efficiency of such coating layer for long-duration characterization of so-called harmonic nanoparticles (HNPs) were shown. The influence of glass surface protection by P(VDF-TrFE) film from an effect of HNPs sticking to the walls of the flow-cell was analyzed for effective studying of the optical harmonics generation efficiency of HNPs making the analysis more robust.
High Permeability Photosintered Strontium Ferrite Flexible Thin Films
Authors: Ahmad Abid , Mishra Bhagyashree , Foley Andrew , Wood Leslie , Chen Maggie Yihong
Published: January 2021

The paper is focused on the development and optimization of strontium ferrite nanomaterial and photosintered flexible thin films. These magnetic thin films are characterized with direct current (DC) and high frequency measurements. For photosintered strontium ferrite samples, we achieved relative complex permeability of about 29.5-j1.8 and relative complex permittivity of about 12.9-j0.3 at a frequency of 5.9 GHz.
Fabrication of Three-Dimensional Microvalves of Internal Nested Structures Inside Fused Silica
Authors: Shan Chao , Yang Qing , Bian Hao , Hou Xun , Chen Feng
Published: January 2021

Nested structures inside the hard material play a pivotal role in the microfluidics systems, such as the microvalve and the micropump. In this article, we demonstrate a novel and facile method of fabricating nested structures inside the fused silica with a two-step process femtosecond laser wet etching (FLWE) process. Inside fused silica, a spherical structure was made with a diameter of nearly 80 µm in a square chamber. In addition, we designed a simple microvalve with this sphere controlling the current’s flow. The novel microvalve structure can be easily integrated into the functional microfluidics systems and will be widely applied in the Lab-on-chip (LOC) system.
Surface Wettability and Electrical Resistance Analysis of Droplets on Indium-Tin-Oxide Glass Fabricated Using an Ultraviolet Laser System
Authors: Tsai Hsin-Yi , Hsu Chih-Ning , Li Cheng-Ru , Lin Yu-Hsuan , Hsiao Wen-Tse , Huang Kuo-Cheng , Yeh J. Andrew
Published: January 2021

Indium tin oxide (ITO) is widely used as a substrate for fabricating chips because of its optical transparency, favorable chemical stability, and high electrical conductivity. However, the wettability of ITO surface is neutral (the contact angle was approximately 90°) or hydrophilic. For reagent transporting and manipulation in biochip application, the surface wettability of ITO-based chips was modified to the hydrophobic or nearly hydrophobic surface to enable their use with droplets. Due to the above demand, this study used a 355-nm ultraviolet laser to fabricate a comb microstructure on ITO glass to modify the surface wettability characteristics. All of the fabrication patterns with various line width and pitch, depth, and surface roughness were employed. Subsequently, the contact angle (CA) of droplets on the ITO glass was analyzed to examine wettability and electrical performance by using the different voltages applied to the electrode. The proposed approach can succeed in the fabrication of a biochip with suitable comb-microstructure by using the optimal operating voltage and time functions for the catch droplets on ITO glass for precision medicine application. The experiment results indicated that the CA of droplets under a volume of 20 μL on flat ITO substrate was approximately 92° ± 2°; furthermore, due to its lowest surface roughness, the pattern line width and pitch of 110 μm exhibited a smaller CA variation and more favorable spherical droplet morphology, with a side and front view CA of 83° ± 1° and 78.5° ± 2.5°, respectively, while a laser scanning speed of 750 mm/s was employed. Other line width and pitch, as well as scanning speed parameters, increased the surface roughness and resulted in the surface becoming hydrophilic. In addition, to prevent droplet morphology collapse, the droplet’s electric operation voltage and driving time did not exceed 5 V and 20 s, respectively. With this method, the surface modification process can be employed to control the droplet’s CA by adjusting the line width and pitch and the laser scanning speed, especially in the neutral or nearly hydrophobic surface for droplet transporting. This enables the production of a microfluidic chip with a surface that is both light transmittance and has favorable electrical conductivity. In addition, the shape of the microfluidic chip can be directly designed and fabricated using a laser direct writing system on ITO glass, obviating the use of a mask and complicated production processes in biosensing and biomanipulation applications.
Thermopneumatic Soft Micro Bellows Actuator for Standalone Operation
Authors: Ahn Seongbeom , Jung Woojun , Ko Kyungho , Lee Yeongchan , Lee Chanju , Hwang Yongha
Published: January 2021

Typical pneumatic soft micro actuators can be manufactured without using heavy driving components such as pumps and power supplies by adopting an independent battery-powered mechanism. In this study, a thermopneumatically operated soft micro bellows actuator was manufactured, and the standalone operation of the actuator was experimentally validated. Thermopneumatic actuation is based on heating a sealed cavity inside the elastomer of the actuator to raise the pressure, leading to deflection of the elastomer. The bellows actuator was fabricated by casting polydimethylsiloxane (PDMS) using the 3D-printed soluble mold technique to prevent leakage, which is inherent in conventional soft lithography due to the bonding of individual layers. The heater, manufactured separately using winding copper wire, was inserted into the cavity of the bellows actuator, which together formed the thermopneumatic actuator. The 3D coil heater and bellows allowed immediate heat transfer and free movement in the intended direction, which is unachievable for conventional microfabrication. The fabricated actuator produced a stroke of 2184 μm, equivalent to 62% of the body, and exerted a force of 90.2 mN at a voltage of 0.55 V. A system in which the thermopneumatic actuator was driven by alkaline batteries and a control circuit also demonstrated a repetitive standalone operation.
Effects of DNA Topology on Transcription from rRNA Promoters in Bacillus subtilis
Authors: Sudzinová Petra , Kambová Milada , Ramaniuk Olga , Benda Martin , Šanderová Hana , Krásný Libor
Published: January 2021

The expression of rRNA is one of the most energetically demanding cellular processes and, as such, it must be stringently controlled. Here, we report that DNA topology, i.e., the level of DNA supercoiling, plays a role in the regulation of Bacillus subtilis σA-dependent rRNA promoters in a growth phase-dependent manner. The more negative DNA supercoiling in exponential phase stimulates transcription from rRNA promoters, and DNA relaxation in stationary phase contributes to cessation of their activity. Novobiocin treatment of B. subtilis cells relaxes DNA and decreases rRNA promoter activity despite an increase in the GTP level, a known positive regulator of B. subtilis rRNA promoters. Comparative analyses of steps during transcription initiation then reveal differences between rRNA promoters and a control promoter, Pveg, whose activity is less affected by changes in supercoiling. Additional data then show that DNA relaxation decreases transcription also from promoters dependent on alternative sigma factors σB, σD, σE, σF, and σH with the exception of σN where the trend is the opposite. To summarize, this study identifies DNA topology as a factor important (i) for the expression of rRNA in B. subtilis in response to nutrient availability in the environment, and (ii) for transcription activities of B. subtilis RNAP holoenzymes containing alternative sigma factors.
A Methodology for Classifying Root Causes of Outbreaks of Legionnaires’ Disease: Deficiencies in Environmental Control and Water Management
Authors: Clopper Benjamin R. , Kunz Jasen M. , Salandy Simone W. , Smith Jessica C. , Hubbard Brian C. , Sarisky John P.
Published: January 2021

We piloted a methodology for collecting and interpreting root cause—or environmental deficiency (ED)—information from Legionnaires’ disease (LD) outbreak investigation reports. The methodology included a classification framework to assess common failures observed in the implementation of water management programs (WMPs). We reviewed reports from fourteen CDC-led investigations between 1 January 2015 and 21 June 2019 to identify EDs associated with outbreaks of LD. We developed an abstraction guide to standardize data collection from outbreak reports and define relevant parameters. We categorized each ED according to three criteria: ED type, WMP-deficiency type, and source of deficiency. We calculated the prevalence of EDs among facilities and explored differences between facilities with and without WMPs. A majority of EDs identified (81%) were classified as process failures. Facilities with WMPs (n = 8) had lower prevalence of EDs attributed to plumbed devices (9.1%) and infrastructure design (0%) than facilities without WMPs (n = 6; 33.3% and 24.2%, respectively). About three quarters (72%) of LD cases and 81% of the fatalities in our sample originated at facilities without a WMP. This report highlights the importance of WMPs in preventing and mitigating outbreaks of LD. Building water system process management is a primary obstacle toward limiting the root causes of LD outbreaks. Greater emphasis on the documentation, verification, validation, and continuous program review steps will be important in maximizing the effectiveness of WMPs.
Potential of Herbaspirillum and Azospirillum Consortium to Promote Growth of Perennial Ryegrass under Water Deficit
Authors: Cortés-Patiño Sandra , Vargas Christian , Álvarez-Flórez Fagua , Bonilla Ruth , Estrada-Bonilla German
Published: January 2021

Plant growth-promoting bacteria (PGPB) can mitigate the effect of abiotic stresses on plant growth and development; however, the degree of plant response is host-specific. The present study aimed to assess the growth-promoting effect of Herbaspirillum (AP21, AP02), Azospirillum (D7), and Pseudomonas (N7) strains (single and co-inoculated) in perennial ryegrass plants subjected to drought. The plants were grown under controlled conditions and subjected to water deficit for 10 days. A significant increase of approximately 30% in dry biomass production was observed using three co-inoculation combinations (p < 0.01). Genomic analysis enabled the detection of representative genes associated with plant colonization and growth promotion. In vitro tests revealed that all the strains could produce indolic compounds and exopolysaccharides and suggested that they could promote plant growth via volatile organic compounds. Co-inoculations mostly decreased the in vitro-tested growth-promoting traits; however, the co-inoculation of Herbaspirillum sp. AP21 and Azospirillum brasilense D7 resulted in the highest indolic compound production (p < 0.05). Although the Azospirillum strain showed the highest potential in the in vitro and in silico tests, the plants responded better when PGPB were co-inoculated, demonstrating the importance of integrating in silico, in vitro, and in vivo assessment results when selecting PGPB to mitigate drought stress.
Synthetic Studies on the Incorporation of N-Acetylallosamine in Hyaluronic Acid-Inspired Thiodisaccharides
Authors: Cristófalo Alejandro E. , Uhrig María Laura
Published: January 2021

Two approaches for the synthesis of the thiodisaccharide β-S-GlcA(1→3)β-S-AllNAc are described here. The target disaccharide was a C-3 epimer and thio-analogue of the hyaluronic acid repetitive unit, tuned with a thiopropargyl anomeric group for further click conjugation. Thus, we analysed and tested two convenient sequences, combining the two key steps required to introduce the thioglycosidic bonds and consequently reach the target molecule: the SN2 substitution of a good leaving group (triflate) present at C-3 of a GlcNAc derivative and the introduction of the anomeric thiopropargyl substituent. The use of a 2-azido precursor showed to be a convenient substrate for the SN2 step. Nevertheless, further protecting group manipulation and the introduction of the thiopropargyl anomeric residue were then required. This approach showed to provide access to a variety of thiodisaccharide derivatives as interesting building blocks for the construction of neoglycoconjugates.
Molecular Simulation and Statistical Learning Methods toward Predicting Drug–Polymer Amorphous Solid Dispersion Miscibility, Stability, and Formulation Design
Authors: Walden Daniel M. , Bundey Yogesh , Jagarapu Aditya , Antontsev Victor , Chakravarty Kaushik , Varshney Jyotika
Published: January 2021

Amorphous solid dispersions (ASDs) have emerged as widespread formulations for drug delivery of poorly soluble active pharmaceutical ingredients (APIs). Predicting the API solubility with various carriers in the API–carrier mixture and the principal API–carrier non-bonding interactions are critical factors for rational drug development and formulation decisions. Experimental determination of these interactions, solubility, and dissolution mechanisms is time-consuming, costly, and reliant on trial and error. To that end, molecular modeling has been applied to simulate ASD properties and mechanisms. Quantum mechanical methods elucidate the strength of API–carrier non-bonding interactions, while molecular dynamics simulations model and predict ASD physical stability, solubility, and dissolution mechanisms. Statistical learning models have been recently applied to the prediction of a variety of drug formulation properties and show immense potential for continued application in the understanding and prediction of ASD solubility. Continued theoretical progress and computational applications will accelerate lead compound development before clinical trials. This article reviews in silico research for the rational formulation design of low-solubility drugs. Pertinent theoretical groundwork is presented, modeling applications and limitations are discussed, and the prospective clinical benefits of accelerated ASD formulation are envisioned.
Photoactive Nanomaterials
Authors: Nuraje Nurxat
Published: January 2021

With the depletion of carbon-based energy resources and the consideration of global warming, renewable energy is considered a promising energy source for future energy [...]