bluuebunny/crossref_metadata_2025 huggingface dataset:
Machine Learning Approximations to Predict Epigenetic Age Acceleration in Stroke Patients
Authors: Fernández-Pérez Isabel , Jiménez-Balado Joan , Lazcano Uxue , Giralt-Steinhauer Eva , Rey Álvarez Lucía , Cuadrado-Godia Elisa , Rodríguez-Campello Ana , Macias-Gómez Adrià , Suárez-Pérez Antoni , Revert-Barberá Anna , Estragués-Gázquez Isabel , Soriano-Tarraga Carolina , Roquer Jaume , Ois Angel , Jiménez-Conde Jordi
Published: February 2023

Age acceleration (Age-A) is a useful tool that is able to predict a broad range of health outcomes. It is necessary to determine DNA methylation levels to estimate it, and it is known that Age-A is influenced by environmental, lifestyle, and vascular risk factors (VRF). The aim of this study is to estimate the contribution of these easily measurable factors to Age-A in patients with cerebrovascular disease (CVD), using different machine learning (ML) approximations, and try to find a more accessible model able to predict Age-A. We studied a CVD cohort of 952 patients with information about VRF, lifestyle habits, and target organ damage. We estimated Age-A using Hannum’s epigenetic clock, and trained six different models to predict Age-A: a conventional linear regression model, four ML models (elastic net regression (EN), K-Nearest neighbors, random forest, and support vector machine models), and one deep learning approximation (multilayer perceptron (MLP) model). The best-performing models were EN and MLP; although, the predictive capability was modest (R2 0.358 and 0.378, respectively). In conclusion, our results support the influence of these factors on Age-A; although, they were not enough to explain most of its variability.
DNA Damage Response Mechanisms in Head and Neck Cancer: Significant Implications for Therapy and Survival
Authors: Papalouka Chara , Adamaki Maria , Batsaki Panagiota , Zoumpourlis Panagiotis , Tsintarakis Antonis , Goulielmaki Maria , Fortis Sotirios P. , Baxevanis Constantin N. , Zoumpourlis Vassilis
Published: February 2023

Head and neck cancer (HNC) is a term collectively used to describe a heterogeneous group of tumors that arise in the oral cavity, larynx, nasopharynx, oropharynx, and hypopharynx, and represents the sixth most common type of malignancy worldwide. Despite advances in multimodality treatment, the disease has a recurrence rate of around 50%, and the prognosis of metastatic patients remains poor. HNCs are characterized by a high degree of genomic instability, which involves a vicious circle of accumulating DNA damage, defective DNA damage repair (DDR), and replication stress. Nonetheless, the damage that is induced on tumor cells by chemo and radiotherapy relies on defective DDR processes for a successful response to treatment, and may play an important role in the development of novel and more effective therapies. This review summarizes the current knowledge on the genes and proteins that appear to be deregulated in DDR pathways, their implication in HNC pathogenesis, and the rationale behind targeting these genes and pathways for the development of new therapies. We give particular emphasis on the therapeutic targets that have shown promising results at the pre-clinical stage and on those that have so far been associated with a therapeutic advantage in the clinical setting.
Safety and Immunogenicity of a Chimeric Subunit Vaccine against Shiga Toxin-Producing Escherichia coli in Pregnant Cows
Authors: Vidal Roberto M. , Montero David A. , Del Canto Felipe , Salazar Juan C. , Arellano Carolina , Alvarez Alhejandra , Padola Nora L. , Moscuzza Hernán , Etcheverría Analía , Fernández Daniel , Velez Victoria , García Mauro , Colello Rocío , Sanz Marcelo , Oñate Angel
Published: February 2023

Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathogen that causes gastroenteritis and Hemolytic Uremic Syndrome. Cattle are the main animal reservoir, excreting the bacteria in their feces and contaminating the environment. In addition, meat can be contaminated by releasing the intestinal content during slaughtering. Here, we evaluated the safety and immunogenicity of a vaccine candidate against STEC that was formulated with two chimeric proteins (Chi1 and Chi2), which contain epitopes of the OmpT, Cah and Hes proteins. Thirty pregnant cows in their third trimester of gestation were included and distributed into six groups (n = 5 per group): four groups were administered intramuscularly with three doses of the formulation containing 40 µg or 100 µg of each protein plus the Quil-A or Montanide™ Gel adjuvants, while two control groups were administered with placebos. No local or systemic adverse effects were observed during the study, and hematological parameters and values of blood biochemical indicators were similar among all groups. Furthermore, all vaccine formulations triggered systemic anti-Chi1/Chi2 IgG antibody levels that were significantly higher than the control groups. However, specific IgA levels were generally low and without significant differences among groups. Notably, anti-Chi1/Chi2 IgG antibody levels in the serum of newborn calves fed with colostrum from their immunized dams were significantly higher compared to newborn calves fed with colostrum from control cows, suggesting a passive immunization through colostrum. These results demonstrate that this vaccine is safe and immunogenic when applied to pregnant cows during the third trimester of gestation.
Disintegration of the NuRD Complex in Primary Human Muscle Stem Cells in Critical Illness Myopathy
Authors: Schneider Joanna , Sundaravinayagam Devakumar , Blume Alexander , Marg Andreas , Grunwald Stefanie , Metzler Eric , Escobar Helena , Müthel Stefanie , Wang Haicui , Wollersheim Tobias , Weber-Carstens Steffen , Akalin Altuna , Di Virgilio Michela , Tursun Baris , Spuler Simone
Published: February 2023

Critical illness myopathy (CIM) is an acquired, devastating, multifactorial muscle-wasting disease with incomplete recovery. The impact on hospital costs and permanent loss of quality of life is enormous. Incomplete recovery might imply that the function of muscle stem cells (MuSC) is impaired. We tested whether epigenetic alterations could be in part responsible. We characterized human muscle stem cells (MuSC) isolated from early CIM and analyzed epigenetic alterations (CIM n = 15, controls n = 21) by RNA-Seq, immunofluorescence, analysis of DNA repair, and ATAC-Seq. CIM-MuSC were transplanted into immunodeficient NOG mice to assess their regenerative potential. CIM-MuSC exhibited significant growth deficits, reduced ability to differentiate into myotubes, and impaired DNA repair. The chromatin structure was damaged, as characterized by alterations in mRNA of histone 1, depletion or dislocation of core proteins of nucleosome remodeling and deacetylase complex, and loosening of multiple nucleosome-spanning sites. Functionally, CIM-MuSC had a defect in building new muscle fibers. Further, MuSC obtained from the electrically stimulated muscle of CIM patients was very similar to control MuSC, indicating the impact of muscle contraction in the onset of CIM. CIM not only affects working skeletal muscle but has a lasting and severe epigenetic impact on MuSC.
A Notional Understanding of the Relationship between Code Readability and Software Complexity
Authors: Tashtoush Yahya , Abu-El-Rub Noor , Darwish Omar , Al-Eidi Shorouq , Darweesh Dirar , Karajeh Ola
Published: February 2023

Code readability and software complexity are considered essential components of software quality. They significantly impact software metrics, such as reusability and maintenance. The maintainability process consumes a high percentage of the software lifecycle cost, which is considered a very costly phase and should be given more focus and attention. For this reason, the importance of code readability and software complexity is addressed by considering the most time-consuming component in all software maintenance activities. This paper empirically studies the relationship between code readability and software complexity using various readability and complexity metrics and machine learning algorithms. The results are derived from an analysis dataset containing roughly 12,180 Java files, 25 readability features, and several complexity metric variables. Our study empirically shows how these two attributes affect each other. The code readability affects software complexity with 90.15% effectiveness using a decision tree classifier. In addition, the impact of software complexity on the readability of code using the decision tree classifier has a 90.01% prediction accuracy.
Deep Learning-Based Real-Time Traffic Sign Recognition System for Urban Environments
Authors: Kim Chang-il , Park Jinuk , Park Yongju , Jung Woojin , Lim Yong-seok
Published: February 2023

A traffic sign recognition system is crucial for safely operating an autonomous driving car and efficiently managing road facilities. Recent studies on traffic sign recognition tasks show significant advances in terms of accuracy on several benchmarks. However, they lack performance evaluation in driving cars in diverse road environments. In this study, we develop a traffic sign recognition framework for a vehicle to evaluate and compare deep learning-based object detection and tracking models for practical validation. We collect a large-scale highway image set using a camera-installed vehicle for training models, and evaluate the model inference during a test drive in terms of accuracy and processing time. In addition, we propose a novel categorization method for urban road scenes with possible scenarios. The experimental results show that the YOLOv5 detector and strongSORT tracking model result in better performance than other models in terms of accuracy and processing time. Furthermore, we provide an extensive discussion on possible obstacles in traffic sign recognition tasks to facilitate future research through numerous experiments for each road condition.
Ectoparasitism of the Flightless Drosophila melanogaster and D. hydei by the Mite Blattisocius mali (Acari: Blattisociidae)
Authors: Michalska Katarzyna , Mrowińska Agnieszka , Studnicki Marcin
Published: February 2023

Predatory mites dispersing by means of insects are often ectoparasites and may use various tactics to get onto the host, counteract its defenses, and diminish its survival. Blattisocius mali is a promising biological control agent which has been reported as transported by several drosophilid species. Our goal was to determine the type of relationship between this mite and fruit flies. We used flightless females of Drosophila melanogaster and D. hydei, which were commercially raised as live pet food. The predatory females mostly attacked the tarsi of the flies and then preferentially moved to the cervix or close to coxa III, where they eventually drilled their chelicerae and started feeding. Although both fly species used similar defensive tactics, more B. mali females did not attack D. hydei or did so with a delay, and a higher percentage of mites fell off the D. hydei tarsi during the first hour of observation. After 24 h, we noted the increased mortality of flies exposed to the presence of mites. Our study indicates the ectoparasitic relationship of B. mali with drosophilids. However, further research is needed to confirm the transport of this mite on wild D. hydei and D. melanogaster, both in the laboratory and under natural conditions.
Comparative Study on Numerical Simulation of Wave-Current Nonlinear Interaction Based on Improved Mass Source Function
Authors: Li Haitao , Lian Jijian , Zhou Enxian , Wang Gang
Published: February 2023

In coastal waters, wave propagation is often affected by rivers and tides. The wave current interaction increases the complexity of the wave propagation. In this study, we consider the Boussinesq type equation with an improved dispersion term as the governing equation and establish a numerical model of wave propagation in the coexistence of wave current environment. Firstly, we use the MIKE 21 BW model to simulate the propagation of dual-frequency waves. The Navier–Stokes equation wave model is used to verify the results and the Fourier transform is used to analyze and discuss the dual-frequency waves. Our findings show that the numerical model established by the Boussinesq equation can better describe the nonlinear interaction between waves more accurately at a much higher computational efficiency compared with the Navier–Stokes equation wave model. In addition, we set the constant current source point in the wave numerical model and conduct the numerical simulation of waves in the current environment, by improving the mass source wave generation method. The numerical simulation of wave-current interactions between uniform and variable water depths is performed, thus demonstrating its capability to describe accurately the influence of water flow on wave propagation.
The Impacts of Dietary Curcumin on Innate Immune Responses and Antioxidant Status in Greater Amberjack (Seriola dumerili) under Ammonia Stress
Authors: Zhou Chuanpeng , Huang Zhong , Zhou Shengjie , Hu Jing , Yang Rui , Wang Jun , Wang Yun , Yu Wei , Lin Heizhao , Ma Zhenhua
Published: February 2023

In this study, we investigated the effect of dietary curcumin on non-specific immune responses and antioxidative ability in Seriola dumerili under ammonia stress and post-recovery. Three diets were prepared to contain 0, 75, and 150 mg/kg of curcumin. A total of 225 greater amberjack (initial weight: 100.90 ± 0.03 g) were distributed into nine cylindrical tanks, constituting an experimental design with three treatments and three replicates. After 56 days of feeding, plasma, intestinal, and hepatic enzyme activities were evaluated. Then, an acute ammonia challenge experiment was conducted. Ten fish per tank were subjected to acute ammonia stress (total ammonia-N: 1000 mg/L) for eight minutes followed by six minutes of recovery. The results indicated that dietary curcumin significantly promoted intestinal and hepatic alkaline phosphatase (ALP) and acid phosphatase (ACP) levels as well as hepatic antioxidative enzymes such as superoxide dismutase (SOD), total antioxidant capacity (T-AOC), reduced glutathione (GSH), and glutathione peroxidase (GSH-Px) of greater amberjack. In addition, curcumin addition improved the activities of antioxidant enzymes, such as SOD, T-AOC, GSH, GSH-Px, and catalase (CAT), and reduced malondialdehyde (MDA) content in liver, spleen, head kidney, and brain tissues after post-recovery. The indexes related to immunity and antioxidant enzymes in the liver, gill, and spleen rose again to some extent, but they showed the worst recovery ability in the head kidney and brain tissue samples. These results indicate that dietary curcumin supplementation could increase non-specific immune responses, antioxidant ability, and enhance resistance to high ammonia stress in juvenile S. dumerili.
Numerical Investigation on the Residual Ultimate Strength of Central-Cracked Stiffened Plates under Tensile and Bending Loads Using XFEM
Authors: Liu Guangzhong , Chen Zhenting , Zhou Jiahao
Published: February 2023

The present paper aims to study the crack propagating behavior of a stiffened plate under tensile and bending displacement load loads. The extended finite element method (XFEM) is used to analyze the residual ultimate strength of stiffened plates with a central crack. The quasi-static crack growth process is simulated by software ABAQUS. The validity of the grid is validated by the plate with a central crack. The numerical method is validated by comparing the fatigue crack growth rate of the round compact tension specimen (RCT) results of the extended finite element with experiment values. Influential parameters, including the size of the stiffened plates, heights of the stiffeners is varied, and uniaxial tensile and four-point bending models are analyzed. The results show that ultimate strength is reduced by the action of tensile and bending loads. The bottom plate and stiffener are destroyed with crack propagation, successively. With the increase in stiffener height, the crack resistance will also increase, thus restraining the central crack growth of stiffened plates.
“Anti-Riot” or “Anti-Protest” Legislation? Black Lives Matter, News Framing, and the Protest Paradigm
Authors: Culver Kathleen Bartzen , McLeod Douglas M.
Published: February 2023

The murder of George Floyd by a Minneapolis police officer on 25 May 2020, sparked widespread protests led by the Black Lives Matter movement throughout the summer of 2020. Subsequent news coverage of these protests prominently featured acts of civil disobedience even though almost all protests were peaceful. In turn, protest “violence” was picked up by conservative political elites as evidence to promote legislation to control protests and keep communities safe. Since summer 2020, eight states have passed such legislation with additional bills pending in 21 states, raising concerns that the legislation suppresses political expression. This paper brings together literature on free expression, the protest paradigm, and news framing to provide the basis for a quantitative and qualitative analysis of 379 news stories and editorials covering Florida’s HB1 protest legislation. Results reveal that the most frequent news frame was fighting crime, with relatively less attention to free expression, political strategy, and race frames. In addition, very little attention was paid to the legislation’s potential chilling effects suppressing constitutionally protected speech and assembly. These results indicate news media were deficient in providing the public with a sufficient assessment of the implications of protest legislation.
Managers’ Perception and Attitude toward Financial Risks Associated with SMEs: Analytic Hierarchy Process Approach
Authors: Alrawad Mahmaod , Lutfi Abdalwali , Almaiah Mohammed Amin , Alsyouf Adi , Al-Khasawneh Akif Lutfi , Arafa Hussin Mostafa , Ahmed Nazar Ali , AboAlkhair Ahmad M. , Tork Magdy
Published: February 2023

This study aimed to identify financial and cash flow risks associated with SMEs and investigated how managers perceived these risks using the analytical hierarchical process (AHP). Accordingly, a three-level decision model was structured using two criteria, probability and consequences, and a list of six different types of risks as decision alternatives. Data were collected by a survey questionnaire from SME managers/owners and analyzed in accordance with the AHP method. The results show that the priority weight for risk criteria was 52% for probability and 48% for consequences. Further, with an average weight of 18.8%, the risk of an increase in bank charges ranked as the highest type of risk faced by SMEs. However, the risk of low or no profits was ranked as the lowest with an average weight of 13.4%. This study is one of the few, if not the first, to investigate SME managers’ perceptions using an AHP method and to provide insightful information on how SME managers/owners perceived various financial and cash flow risks. The study results may support the use of the AHP method in understanding managers’ perceptions and attitudes toward various types of risks associated with SMEs.
A Will and a Way: Making Displaced Children’s Right to Education Enforceable
Authors: Van Esveld Bill
Published: February 2023

All children have the right to education without discrimination, but half of refugee children are out of school, far worse than global averages. Obstacles to education for refugee and migrant children include poverty and overstretched resources in host countries, and humanitarian donors and agencies have important roles and should ensure the right to education. However, policy barriers to education are key drivers of the education crisis facing displaced children. These policy barriers are internationally unlawful, but the children affected often lack standing under domestic law to demand a remedy. Countries with laws enshrining migrant, asylum-seeking, and refugee children’s rights to education and the European Union’s response to Ukrainian refugee learners provide examples that advocates can use to help raise the global floor for displaced children’s right to education. Advocates should press all countries to grant all children, including migrants and refugees, the enforceable right to education in domestic law.
Supply Chain 4.0: New Generation of Supply Chain Management
Authors: Yuan Xue-Ming , Xue Anrong
Published: February 2023

Industry 4 [...]
Optimization of Hexagonal Structure for Enhancing Heat Transfer in Storage System
Authors: Raźny Natalia , Dmitruk Anna , Nemś Artur , Nemś Magdalena , Naplocha Krzysztof
Published: February 2023

Thermal performance was tested during cycling work for latent heat storage systems based on KNO3 and NaNO3 (weight ratio 54:46). For heat transfer improvement, cast aluminum honeycomb-shaped structures were produced via 3D printing of polymer model and investment casting. Different wall thicknesses were tested at 1.2 mm and 1.6 mm. The obtained results were compared to working cycles of pure PCM bed. The use of enhancers is reported to improve the rate of charging and discharging of the deposit. In the next step, the structures were examined with numerical simulation performed with ANSYS Fluent software. The wall thicknesses taken into consideration were the following: 0.8, 1.2, 1.6, and 2.0 mm. An insert with a greater wall thickness allows for smaller dT/dt and better heat distribution in the vessel. The investment casting process enables the manufacturing of complex structures of custom shapes without porosity and contamination.
Freeze Drying of Polymer Nanoparticles and Liposomes Exploiting Different Saccharide-Based Approaches
Authors: Andreana Ilaria , Bincoletto Valeria , Manzoli Maela , Rodà Francesca , Giarraputo Vita , Milla Paola , Arpicco Silvia , Stella Barbara
Published: February 2023

Biodegradable nanocarriers represent promising tools for controlled drug delivery. However, one major drawback related to their use is the long-term stability, which is largely influenced by the presence of water in the formulations, so to solve this problem, freeze-drying with cryoprotectants has been proposed. In the present study, the influence of the freeze-drying procedure on the storage stability of poly(lactide-co-glycolide) (PLGA) nanoparticles and liposomes was evaluated. In particular, conventional cryoprotectants were added to PLGA nanoparticle and liposome formulations in various conditions. Additionally, hyaluronic acid (HA), known for its ability to target the CD44 receptor, was assessed as a cryoprotective excipient: it was added to the nanocarriers as either a free molecule or conjugated to a phospholipid to increase the interaction with the polymer or lipid matrix while exposing HA on the nanocarrier surface. The formulations were resuspended and characterized for size, polydispersity index, zeta potential and morphology. It was demonstrated that only the highest percentages of cryoprotectants allowed the resuspension of stable nanocarriers. Moreover, unlike free HA, HA-phospholipid conjugates were able to maintain the particle mean size after the reconstitution of lyophilized nanoparticles and liposomes. This study paves the way for the use of HA-phospholipids to achieve, at the same time, nanocarrier cryoprotection and active targeting.
Shungite (Mineralized Carbon) as a Promising Electrode Material for Electroanalysis
Authors: Sýs Milan , Bártová Michaela , Bartoš Martin , Švancara Ivan , Mikysek Tomáš
Published: February 2023

In this study, two different types of amorphous carbonaceous Precambrian rock, classified as noble elite shungite and black raw shungite, were tested as possible electrode materials of natural origin. Both types were machined into cylindrical shapes to form the corresponding solid electrodes and their physicochemical and electrochemical properties were compared with the standard glassy carbon electrode (GCE). The raw stones were first subjected to microscopic imaging by using scanning electron microscopy and energy-dispersive X-ray spectroscopy, both of which indicated significant differences in their morphology and in the content of impurities. An electrode prototype manufactured from noble elite shungite (EShE) with a carbon content of about 94% (w/w) has offered a very satisfactory electrochemical performance with a nearly identical heterogeneous electron-transfer rate constant of 7.8 × 10−3 cm s−1 for ferro/ferricyanide redox couple, a slightly narrower potential range (~2.1 V) and a relatively low double-layer capacitance (of ca. 50 μF), resulting in low background currents comparable to those at the GCE. In contrast, the second electrode based on black raw shungite (BShE) with a carbon content of ca. 63% (w/w) exhibited markedly worse electrochemical properties and more than four times higher double-layer capacitance, both of which were probably due to the presence of poorly conductive impurities. The whole study has been completed with three different examples of electroanalytical applications, revealing that the first type, EShE, is a more suitable material for the preparation of electrodes and may represent a cheap alternative to commercially marketed products.
Drop Weight Testing of Samples Made of Different Building Materials Designed for the Protection of Classified Information
Authors: Durica Jakub , Velas Andrej , Boros Martin , Sovjak Radoslav , Konrad Petr , Kheml Premysl
Published: February 2023

Classified information is information of vital importance to the State, which must be protected against disclosure, misuse, damage, unauthorized reproduction, destruction, loss or theft in the interest of the State. At present, there are four levels of classification. For each classification level, precise requirements are laid down for the material of the walls, partitions and ceilings of the rooms in which classified information is stored. Several types of materials are defined for each classification level. The objective of this study was to test and determine whether the different types of materials proposed for the Confidential level meet the same level of resistance. A drop weight test via pendulum was used to determine the resistance. A 50 kg weight was used to break through a 60 × 100 cm sample. The impact of the weight was on the exact center of the sample. The result of the tests was that to break through samples of different materials, large differences in the drop height of the weight were required. The most resistant was the specimen made of reinforced concrete, which required 3 impacts from a height of 80 cm to break through. On the contrary, the least resistant were the specimens made of masonry of autoclaved aerated concrete, where after 2 falls from a height of 5 cm, the sample broke into 2 parts.
Synthesis of Metakaolin Based Alkali Activated Materials as an Adsorbent at Different Na2SiO3/NaOH Ratios and Exposing Temperatures for Cu2+ Removal
Authors: Ibrahim Masdiyana , Wan Ibrahim Wan Mastura , Abdullah Mohd Mustafa Al Bakri , Nabialek Marcin , Putra Jaya Ramadhansyah , Setkit Monthian , Ahmad Romisuhani , Jeż Bartłomiej
Published: February 2023

Water contamination is a major issue due to industrial releases of hazardous heavy metals. Copper ions are among the most dangerous heavy metals owing to their carcinogenicity and harmful effects on the environment and human health. Adsorption of copper ions using alkali activated materials synthesized through the polycondensation reaction of an alkali source and aluminosilicates is the most promising technique, and has a high adsorption capability owing to a large surface area and pore volume. This research focuses on the effect of the alkaline activator ratio, which is a sodium silicate to sodium hydroxide ratio. Various exposing temperatures on metakaolin based alkali activated materials on a surface structure with excellent functional properties can be used as adsorbent materials for the removal of copper ions. A variety of mix designs were created with varying sodium silicate to sodium hydroxide ratios, with a fixed sodium hydroxide molarity, metakaolin to alkali activator ratio, hydrogen peroxide, and surfactant content of 10 M, 0.8, 1.00 wt%, and 3.0 wt%, respectively. Most wastewater adsorbents need high sintering temperatures, requiring an energy-intensive and time-consuming manufacturing process. In this way, metakaolin-based alkali activated materials are adsorbent and may be produced easily by solidifying the sample at 60 °C without using much energy. The specific surface area, water absorption, microstructure, phase analysis, functional group analysis, and adsorption capability of copper ions by metakaolin based alkali activated materials as adsorbents were evaluated. The water absorption test on the samples revealed that the sodium silicate to sodium hydroxide 0.5 ratio had the highest water absorption percentage of 36.24%, superior pore size distribution, and homogeneous porosity at 60 °C, with a surface area of 24.6076 m2/g and the highest copper ion uptake of 63.726 mg/g with 95.59% copper ion removal efficiency at adsorption condition of pH = 5, a dosage of 0.15 g, 100 mg/L of the initial copper solution, the temperature of 25 °C, and contact time of 60 min. It is concluded that self-supported metakaolin based alkali activated material adsorbents synthesized at low temperatures effectively remove copper ions in aqueous solutions, making them an excellent alternative for wastewater treatment applications.
Tribological Behaviour of Enamel Coatings Created by a Prototype Device for Local Repair of Inorganic Surfaces
Authors: Müller Miroslav , Hromasová Monika , Valášek Petr , Nováková Iva , Moravec Jaromír , Jelínek Milan
Published: February 2023

The ability of materials to withstand environmental influences is a frequent necessity in many industries. Special requirements are imposed by such industries where surfaces are affected by acidity during the processing or storage of products. In such cases, when the basic surface is exposed to chemical influences, it is possible to use enamel coatings, which, with their properties, guarantee the protection of the surface and achieve the required service life of the material. This article deals mainly with the interaction between the base material and the enamel and its resistance to wear between the original and the renovated surface caused by local heating. The article presents a methodical procedure for the preparation of test specimens with an enamel layer prepared by AWJ cutting, eliminating its damage. There are minimal differences in the microstructure between the original and the renovated surface due to the production technique. The renovated enamel surface had more bubbles of a larger size than the original surface. Good adhesion between the base metal material (substrate) and the ground coat was demonstrated. The tested surfaces demonstrated high resistance to intensive abrasion conditions with low linear wear increments.
Fatigue of an Aluminum Foam Sandwich Formed by Powder Metallurgy
Authors: Liu Sitian , Huang Peng , Sun Xi , Zeng Wenqi , Zhang Jiatong , Zu Guoyin
Published: February 2023

In this paper, an aluminum foam sandwich (AFS) was prepared by the rolling composite-powder metallurgy method, and its fatigue properties were studied. It was compared with an AFS made by the adhesive method to study its fatigue properties more directly. In this experiment, the fatigue performance was investigated by studying the microscopic interface, fatigue life, deflection curve, and failure mode. The results show that the fatigue life of an AFS with the rolling composite-powder metallurgy method is much longer than that with the adhesive method. The failure mode of an AFS made by the rolling composite-powder metallurgy method is shear failure, and that of an AFS made by the adhesive method is shear failure and interface debonding. An AFS with the rolling composite-powder metallurgy method has better fatigue properties. This paper also explored the fatigue damage model using the fatigue modulus method, and the polynomial fitting method has a higher fitting degree.
Effect of the Sorption Layer on the Protection Time Provided by Anti-Smog Half-Masks
Authors: Brochocka Agnieszka , Owczarek Oliwia , Wojtkiewicz Mateusz
Published: February 2023

This paper presents the results of a study examining the protection time of half-masks containing different types and quantities of carbon sorbents. The protection time afforded by the half-masks was determined by analyzing the adsorption of three substances harmful to human health at their maximum allowable concentrations. Two of the tested half-masks showed comprehensive protection against pollutants contained in smog. Among the tested half-masks, the one with the best protective properties was identified. The longest protection time (over 8 h) was recorded for toluene, followed by over 7 h for sulfur dioxide, and only 2 h for cyclohexane. The morphological structure of nonwovens incorporating the carbon sorbents was examined under a microscope. The study showed that protection time depends on the size of activated carbon particles incorporated in the nonwoven structure as well as on their distribution. Based on these results, we identified the most effective morphological structure of the sorbent in the nonwovens.
Degradation Mechanism of Coal Gangue Concrete Suffering from Sulfate Attack in the Mine Environment
Authors: Yu Linli , Xia Junwu , Gu Jixin , Zhang Shuai , Zhou Yu
Published: February 2023

Recycling coal gangue as aggregate to produce concrete in situ is the most effective way to solve the problem of deposited coal gangue in mines. Nevertheless, the mine environment underground is rich in sulfate ions, posing a threat to the durability of coal gangue concrete (CGC). Hence, the degradation process of sulfate-attacked CGC is investigated. A series of tests is performed to evaluate its variation law of mass, dynamic elastic modulus, compressive strength and sulfate ion distribution. Meanwhile, the microstructure and phases of sulfate-attacked CGC are identified by scanning electron microscopy, X-ray diffraction and thermogravimetric analysis. The results indicate that the residual compressive strength ratio of CGC is higher than that of normal concrete after a 240 d sulfate attack, implying a superior sulfate resistance for CGC. Additionally, the higher the sulfate concentration, the more severe the degradation. Except for the secondary hydration of CGC itself, the diffused sulfate ions also react with Ca(OH)2, forming gypsum and ettringite; this plays a positive role in filling the pores at the early stage, whereas, at the later stage, the generated micro-cracks are detrimental to the performance of CGC. In particular, the proposed sulfate corrosion model elucidates the degradation mechanism of CGC exposed to a sulfate-rich environment.
Effects of Thermal Treatment on the Mechanical Properties of Bamboo Fiber Bundles
Authors: Cui Jie , Fu Daixin , Mi Lin , Li Lang , Liu Yongjie , Wang Chong , He Chao , Zhang Hong , Chen Yao , Wang Qingyuan
Published: February 2023

Bamboo is known as a typical kind of functional gradient natural composite. In this paper, fiber bundles were extracted manually from various parts of the stem in the radial direction, namely the outer, middle, and inner parts. After heat treatment, the mechanical properties of the fiber bundles were studied, including the tensile strength, elastic modulus, and fracture modes. The micromechanical properties of the fiber cell walls were also analyzed. The results showed that the mean tensile strength of the bamboo fiber bundles decreased from 423.29 to 191.61 MPa and the modulus of elasticity increased from 21.29 GPa to 27.43 GPa with the increase in temperature. The elastic modulus and hardness of the fiber cell walls showed a positive correlation with temperature, with the modulus of elasticity and the hardness increasing from 15.96 to 18.70 GPa and 0.36 to 0.47 GPa, respectively. From the outside to the inside of the bamboo stems, the tensile strength and elastic modulus showed a slight decrease. The fracture behavior of the fiber bundles near the outside approximates ductile fracture, while that of the bundles near to the inside tend to be a brittle fracture. The fracture surfaces of the bamboo bundles and the single fibers became smoother after heat treatment. The results show that bamboo fiber bundles distributed near the outside are most suitable for industrial development under heat treatment at 180 °C. Therefore, this study can provide a reasonable scientific basis for the selective utilization, functional optimization, and bionic utilization of bamboo materials, which has very important theoretical and practical significance.
OLED Structure Optimization for Pure and Efficient NIR Electroluminescence of Nd3+ Complexes Bearing Fluorinated 1,3-Diketones
Authors: Metlina Daria A. , Goryachii Dmitry O. , Metlin Mikhail T. , Mikhalchenko Lyudmila V. , Korshunov Vladislav M. , Taydakov Ilya V.
Published: February 2023

NIR emitting OLEDs (organic light-emitting diodes) with high photoluminescence quantum yields were developed on the basis of fluorinated 1,3-diketonate coordination compounds of the Nd3+ ion. Both thermal evaporation and spin-coating techniques were successfully employed for active layer deposition resulting in electroluminescence quantum yields up to 1.38·10−2%. Blueish-green emission from exciplex and electroplax formations was almost suppressed with the topology optimization of the cell.
The Influence of Annealing at 500 and 900 °C on the Structure and Mechanical Properties of AlxCoCrFeNi Alloys
Authors: Tokarewicz Marzena , Grądzka-Dahlke Małgorzata , Rećko Katarzyna , Łępicka Magdalena
Published: February 2023

The AlCoCrFeNi high-entropy alloy is sensitive to heat treatment. The aim of the present study was to test a similar correlation for AlxCoCrFeNi alloys with less than equimolar aluminum content. This paper presents a study of the annealing effect on the structure and mechanical properties of selected alloys. AlxCoCrFeNi alloys (x = 0, 0.5, 0.7) were fabricated by the induction melting method. The obtained specimens were annealed at 500 °C and 900 °C. A detailed study of the changes in crystalline structure due to annealing was conducted. Three-point bending and hardness tests were carried out for the as-cast and annealed specimens to determine selected mechanical properties. The study confirmed that increasing the aluminum content in the AlxCoCrFeNi alloy improves mechanical properties. For the alloy with aluminum content x = 0.7, hardness increased by 187% and yield strength by 252% compared to the alloy without aluminum. A significant effect of annealing on the crystalline structure of the Al0.7CoCrFeNi alloy was found, but this was not followed by changes in mechanical properties.
Effect of Al-5Ti-0.25C-0.25B and Al-5Ti-1B Master Alloys on the Microstructure and Mechanical Properties of Al-9.5Si-1.5Cu-0.8Mn-0.6Mg Alloy
Authors: Wen Yihan , Wu Yuying , Wu Yongjie , Gao Tong , Wei Zuoshan , Liu Xiangfa
Published: February 2023

The goal of this research was to determine how the master alloys Al-5Ti-0.25C-0.25B and Al-5Ti-1B affected the mechanical properties and structural characteristics of the alloy Al-9.5Si-1.5Cu-0.8Mn-0.6Mg. Field emission scanning electron microscopy (FE-SEM) was used to probe the microscopic composition, and the mechanical properties were evaluated using tensile testing. The results showed that, by adding 0.5% Al-5Ti-0.25C-0.25B master alloy and 0.5% Al-5Ti-1B master alloy, the α-Al dendrites can be significantly refined. In the extrusion state, the ultimate tensile strength and elongation with 0.5% Al-5Ti-0.25C-0.25B master alloy reached 380 MPa and 11.2%, which were 5.5% and 22.4% higher than no refinement, respectively. The elongation of the samples with the Al-5Ti-1B alloy addition increased from 9% to 11.9%, which is attributed to the fact that more pronounced complete recrystallization occurred during the extrusion heat treatment.
Extending the Protection Ability and Life Cycle of Medical Masks through the Washing Process
Authors: Volmajer Valh Julija , Pušić Tanja , Čurlin Mirjana , Knežević Ana
Published: February 2023

The reuse of decontaminated disposable medical face masks can contribute to reducing the environmental burden of discarded masks. This research is focused on the effect of household and laboratory washing at 50 °C on the quality and functionality of the nonwoven structure of polypropylene medical masks by varying the washing procedure, bath composition, disinfectant agent, and number of washing cycles as a basis for reusability. The barrier properties of the medical mask were analyzed before and after the first and fifth washing cycle indirectly by measuring the contact angle of the liquid droplets with the front and back surface of the mask, further by measuring air permeability and determining antimicrobial resistance. Additional analysis included FTIR, pH of the material surface and aqueous extract, as well as the determination of residual substances—surfactants—in the aqueous extract of washed versus unwashed medical masks, while their aesthetic aspect was examined by measuring their spectral characteristics. The results showed that household washing had a stronger impact on the change of some functional properties, primarily air permeability, than laboratory washing. The addition of the disinfectant agent, didecyldimethylammonium chloride, contributes to the protective ability and supports the idea that washing of medical masks under controlled conditions can preserve barrier properties and enable reusability.
Chemically Activated Carbon Based on Biomass for Adsorption of Fe(III) and Mn(II) Ions from Aqueous Solution
Authors: Elewa Amal M. , Amer Ahmed A. , Attallah Mohamed F. , Gad Hamdy A. , Al-Ahmed Zehbah Ali Mohamed , Ahmed Inas A.
Published: February 2023

Rice husk was converted into activated carbon (AC) as a byproduct of agricultural waste in an electric furnace at 700 °C and chemically activated using three distinct processes: NaOH AC(C), acetic acid AC(C-1), phosphoric acid AC(C-2), and carbonization AC(C-3) without any chemical activation. To characterize the activated carbon and the removal efficiencies of Fe(III) and Mn(II) from aqueous solutions, various analytical tools were used. The results revealed that the capacities of the four adsorbents to adsorb Fe(III) or Mn(II) from an aqueous solution differ significantly. AC(C-3) was chosen for additional research. The impact of different operational factors, including pH, contact time, adsorbent dosage, starting metal ion concentration, interfering ions, and temperature, were investigated. The optimum pH values for Fe(III) and Mn(II) adsorption were found to be pH 3 and pH 6, respectively. The results obtained were utilized to assess the kinetics and thermodynamics of the adsorption process. The sorption of Fe(III) and Mn(II) ions was found to be a pseudo-second-order kinetic process, and the equilibrium data were fitted with the Langmuir isotherm. Additionally, the evidence suggests that an endothermic mechanism governs the adsorption process. The maximum adsorption capacities of Fe(III) and Mn(II) were 28.9 and 73.47 mg/g, respectively.
Analysis of Acoustic Emission Signals Processed with Wavelet Transform for Structural Damage Detection in Concrete Beams
Authors: Machorro-Lopez Jose M. , Hernandez-Figueroa Jorge A. , Carrion-Viramontes Francisco J. , Amezquita-Sanchez Juan P. , Valtierra-Rodriguez Martin , Crespo-Sanchez Saul E. , Yanez-Borjas Jesus J. , Quintana-Rodriguez Juan A. , Martinez-Trujano Luis A.
Published: February 2023

Concrete beams are elements used in many civil structures; unfortunately, they can contain cracks that lead to the collapse of the structures if those defects are not detected early enough. In this article, a new method to determine the structural condition of concrete beams subjected to bending is proposed. In general, it is based on the processing of the acoustic emissions (AE) signals, which are generated during the application of a load, by using the mathematical tool called wavelet transform (WT). The sound of the internal energy/crack is recorded as a hit or AE signal event; then, those signals acquired as waveforms are post-processed with the continuous WT (CWT); then, the wavelet energy (WE) is calculated for each hit by using an adequate scale range and the most convenient mother wavelet. Thus, with this method, it is possible to determine the structural condition (healthy or damaged) of concrete beams subjected to bending just by calculating the WE of any hit at any time and, even more, it is possible to define more precisely the stage of the structural condition as a healthy condition, micro-cracks appearance, the manifestation of a principal crack (hit with the highest WE), propagation of the principal crack, and final rupture. This method is experimentally validated in the laboratory, and additionally, ultrasonic pulse velocity tests (UPVT) are performed for some specimens to confirm the change between healthy and damaged conditions. The results are promising in order to apply this effective method in concrete beams of real-life structures.
Bisecting for Selecting: Using a Laplacian Eigenmaps Clustering Approach to Create the New European Football Super League
Authors: Bond Alexander John , Beggs Clive B.
Published: February 2023

Ranking sports teams generally relies on supervised techniques, requiring either prior knowledge or arbitrary metrics. In this paper, we offer a purely unsupervised technique. We apply this to operational decision-making, specifically, the controversial European Super League for association football, demonstrating how this approach can select dominant teams to form the new league. We first use random forest regression to select important variables predicting goal difference, which we use to calculate the Euclidian distances between teams. Creating a Laplacian eigenmap, we bisect the Fiedler vector to identify the natural clusters in five major European football leagues. Our results show how an unsupervised approach could identify four clusters based on five basic performance metrics: shots, shots on target, shots conceded, possession, and pass success. The top two clusters identify teams that dominate their respective leagues and are the best candidates to create the most competitive elite super league.
Attention Knowledge Network Combining Explicit and Implicit Information
Authors: Deng Shangju , Qin Jiwei , Wang Xiaole , Wang Ruijin
Published: February 2023

The existing knowledge graph embedding (KGE) method has achieved good performance in recommendation systems. However, the relevancy degree among entities reduces gradually along the spread in the knowledge graph. Focusing on the explicit and implicit relationships among entities, this paper proposes an attention knowledge network combining explicit and implicit information (AKNEI) to effectively capture and exactly describe the correlation between entities in the knowledge graph. First, we design an information-sharing layer (ISL) to realize information sharing between projects and entities through implicit interaction. We innovatively propose a cross-feature fusion module to extract high-order feature information in the model. At the same time, this paper uses the attention mechanism to solve the problem of the decline of information relevance in the process of knowledge graph propagation. Finally, the features of KGE and cross feature fusion module are integrated into the end-to-end learning framework, the item information in the recommendation task and the knowledge graph entity information are interacted implicitly and explicitly, and the characteristics between them are automatically learned. We performed extensive experiments on multiple public datasets that include movies, music, and books. According to the experimental results, our model has a great improvement in performance compared with the latest baseline.