bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of Highly Effective Treatment in Pediatric-Onset Multiple Sclerosis: A Case Series
Authors: Immovilli Paolo , De Mitri Paola , Bazzurri Veronica , Vollaro Stefano , Morelli Nicola , Biasucci Giacomo , Magnifico Fabiola , Marchesi Elena , Lombardelli Maria Lara , Gelati Lorenza , Guidetti Donata
Published: November 2022

Introduction: Pediatric-onset multiple sclerosis (POMS) is characterized by high inflammatory disease activity. Our aim was to describe the treatment sequencing and report the impact highly effective disease-modifying treatment (HET) had on disease activity. Materials and Methods: Five consecutive patients with POMS were administered HET following lower efficacy drug or as initial therapy. Data on treatment sequencing, relapses and MRIs were collected during the follow-up. Results: Our patients had an average age of 13.8 years (range 9–17) at diagnosis and 13.4 years (range 9–16) at disease onset, and 2/5 (40%) POMS were female. The pre-treatment average annualized relapse rate was 1.6 (range 0.8–2.8), and the average follow-up length was 5 years (range 3–7). A total of 2/5 (40%) patients were stable on HET at initial therapy, and 3/5 (60%) required an escalation to more aggressive treatment, even if two of them had been put on HET as initial treatment. Four out of five patients (80%) had No Evidence of Disease Activity-3 status (NEDA-3) at an average follow-up of 3 years (range 2–5). Conclusion: It has been observed that in a recent time period all the cases had prompt diagnosis, early HET or escalation to HET with a good outcome in 80% of the cases.
The Role of WRAP53 in Cell Homeostasis and Carcinogenesis Onset
Authors: Gadelha Renan Brito , Machado Caio Bezerra , Pessoa Flávia Melo Cunha de Pinho , Pantoja Laudreísa da Costa , Barreto Igor Valentim , Ribeiro Rodrigo Monteiro , de Moraes Filho Manoel Odorico , de Moraes Maria Elisabete Amaral , Khayat André Salim , Moreira-Nunes Caroline Aquino
Published: November 2022

The WD repeat containing antisense to TP53 (WRAP53) gene codifies an antisense transcript for tumor protein p53 (TP53), stabilization (WRAP53α), and a functional protein (WRAP53β, WDR79, or TCAB1). The WRAP53β protein functions as a scaffolding protein that is important for telomerase localization, telomere assembly, Cajal body integrity, and DNA double-strand break repair. WRAP53β is one of many proteins known for containing WD40 domains, which are responsible for mediating a variety of cell interactions. Currently, WRAP53 overexpression is considered a biomarker for a diverse subset of cancer types, and in this study, we describe what is known about WRAP53β’s multiple interactions in cell protein trafficking, Cajal body formation, and DNA double-strand break repair and its current perspectives as a biomarker for cancer.
Genome-Based Taxa Delimitation (GBTD): A New Approach
Authors: Bolbat Alexander , Bukin Yurij , Kaygorodova Irina
Published: November 2022

Proper taxonomic identification is essential for biological research. Unfortunately, there are no clear guidelines for taxonomic assignment above the species level. Here, we present a novel approach—GBTD—to the use of genetic divergence to evaluate the taxonomic position of certain samples with simultaneous estimation of the current systematics correctness. This approach includes measuring the raw and model-adjusted distances between DNA sequences and attributing them to the lowest taxonomic levels that are common in sample pairs to reveal distance distributions matching different taxonomic levels (species, genus, family etc.). GBTD facilitated the reassessment of the taxonomic position of the samples, whose genetic distances relative to other samples in the dataset did not match their taxonomic divergence. A data set of complete mitochondrial genome sequences of segmented worms was chosen to test this approach. As a result, numerous inconsistencies in the systematics of samples from GenBank were pointed out. These inconsistencies included both the oversplitting and overlumping of individuals into taxa of different levels and clear cases of misidentification. Our approach sparks re-evaluation of the current systematics where traditional methods fail to provide sufficient resolution.
Physical Activity, Well-Being, and the Needs of Canadians with Disabilities during the COVID-19 Pandemic
Authors: Gee Cameron M. , Hoekstra Femke , Úbeda-Colomer Joan , Knibbe Tara Joy , DaSilva Pinder , Ginis Kathleen A. Martin
Published: November 2022

Background: This study examined self-reported physical activity (PA) participation, well-being, and perceived needs of Canadians with disabilities during the COVID-19 pandemic. In addition, we assessed physical and mental health and the extent to which pre-identified needs were being met or unmet. Methods: Two iterations of the COVID-19 Disability Survey were conducted during two pandemic timeframes: June–December 2020 (iteration 1, n = 599) and December 2020–September 2021 (iteration 2, n = 528). PA participation was assessed with the International Physical Activity Questionnaire. Physical and mental health were assessed with the PROMIS Global-10 questionnaire. A needs assessment was conducted on 11 needs pre-identified in partnership with community organizations. Results: Approximately 50% of respondents to both iterations reported that they did not do any moderate-vigorous intensity PA. While physical health was not different between timeframes, mental health was worse during iteration 2 than iteration 1 (p = 0.028). During both timeframes, access to recreation and leisure facilities was the greatest unmet need. Conclusion: These data highlight the low levels of PA and the perceived changes in PA, mental health, and recreational needs of Canadians with disabilities during the pandemic. The findings of the Survey were used to support policy change to remove barriers to PA participation for people with disabilities in Ontario.
Determinants of Default Probability for Audited and Unaudited SMEs under Stressed Conditions in Zimbabwe
Authors: Matenda Frank Ranganai , Sibanda Mabutho
Published: November 2022

Using stepwise logistic regression models, the study aims to separately detect and explain the determinants of default probability for unaudited and audited small-to-medium enterprises (SMEs) under stressed conditions in Zimbabwe. For effectiveness purposes, we use two separate datasets for unaudited and audited SMEs from an anonymous Zimbabwean commercial bank. The results of the paper indicate that the determinants of default probability for unaudited and audited SMEs are not identical. These determinants include financial ratios, firm and loan characteristics, and macroeconomic variables. Furthermore, we discover that the classification rates of SME default prediction models are enhanced by fusing financial ratios and firm and loan features with macroeconomic factors. The study highlights the vital contribution of macroeconomic factors in the prediction of SME default probability. We recommend that financial institutions model separately the default probability for audited and unaudited SMEs. Further, it is recommended that financial institutions should combine financial ratios and firm and loan characteristics with macroeconomic variables when designing default probability models for SMEs in order to augment their classification rates.
Measuring the Level of the Youth Informal Economy in Lithuania in 2004–2020
Authors: Morkunas Mangirdas
Published: November 2022

This paper investigates the development of the youth informal economy in Lithuania in 2004–2020. Specific youth-tailored multiple indicators multiple causes (MIMIC) model has been derived in order to estimate the level of the youth informal economy. In total, 173 direct phone interviews with company managers were conducted in order to acquire information for the MIMIC model calibration. It was revealed that during the investigated period, the youth informal economy fluctuated between 38.7% and 46.1% and was significantly higher compared with the overall informal economy in Lithuania. Although showing a strong correlation level (0.742) the overall informal economy within the country and the youth informal economy show slightly different developmental paths, the latter being more prone to higher increases during a crisis period.
Understanding the Relationship between Culturally Engaging Campus Environments and College Students’ Academic Motivation
Authors: Museus Samuel D. , Shiroma Kiana
Published: November 2022

Low rates of college completion are a major national dilemma, and one way in which college campuses can increase degree attainment rates is by fostering higher levels of academic motivation among students. This study analyzed the relationship between culturally engaging campus environments and growth in college students’ academic motivation. The survey data from a sample of 704 undergraduates enrolled at a public four-year university on the East Coast were analyzed. Bivariate correlations indicate that all nine indicators of culturally engaging campus environments were correlated with stronger academic motivation. When controlling for demographic and high school variables, cultural validation and humanized environments were directly and positively associated with growth in academic motivation. However, post hoc analysis reveals that cultural familiarity, culturally relevant knowledge, cross-cultural engagement, and collectivist orientation were all indirectly associated with motivation gains through cultural validation. The implications of this study for research include the need for research that analyzes these relationships with larger samples from more diverse institutions and utilizes methods that support stronger causal claims. Implications for practice include the importance of maximizing students’ access to culturally engaging environments and ensuring that they are designed with anti-deficit approaches that validate students’ backgrounds and identities to enhance academic motivation.
The Relationship between Executive Functions and Dance Classes in Preschool Age Children
Authors: Chichinina Elena , Bukhalenkova Daria , Tvardovskaya Alla , Semyonov Yury , Gavrilova Margarita , Almazova Olga
Published: November 2022

The development of executive functions is of the utmost importance for academic success at school and the social adaptation of children. Dance class attendance is one of the factors promoting the development of these functions in children. This study was aimed to explore the relationship between extra dance class attendance and executive functions in preschool age children. The executive function level was assessed using NEPSY-II subtests “Sentences Repetition”, “Memory for Designs”, “Inhibition”, “Statue”, and “Dimensional Change Card Sort”. The data on extra dance classes were collected by means of a questionnaire for parents. In the study, 86 typically developing 5–6-year-old children participated. No statistically significant differences in executive functions’ levels were discovered in children taking only extra dance classes for at least 6 months and children taking no extra classes. The obtained data plays an important role for the design of further investigations of the topic.
The Mediating Effects of Specific Types of Self-Efficacy on the Relationship between Math Anxiety and Performance
Authors: Jameson Molly M. , Dierenfeld Celeste , Ybarra Julia
Published: November 2022

The negative relationship between math anxiety and math performance is well-supported in the literature. The important role of students’ math self-efficacy (i.e., their confidence in their ability to successfully complete specific math tasks) in this relationship is also established. Self-efficacy is extremely specific, however, and it is possible that additional types of self-efficacy can play a role in the relationship between anxiety and performance. This study surveyed 118 undergraduate students on their math anxiety, math performance, math self-efficacy, emotional self-efficacy, and emotional self-efficacy specifically in math to determine the mediating effects of these specific types of self-efficacy. Hierarchical linear regression shows that math self-efficacy continues to fully mediate the relationship between anxiety and performance; in the current study, emotional self-efficacy partially mediated the relationship while emotional self-efficacy specifically in math did not. The role of emotional self-efficacy should be further explored, as these findings are contrary to previous work. Educational interventions should continue to emphasize building students’ math confidence to improve the math performance of math-anxious students.
Factors Affecting Early Literacy Learning Spaces of Young Children: The Context of Home Literacy in Saudi Arabia
Authors: Alsubaie Merfat Ayesh
Published: November 2022

This study explores the factors affecting the early literacy learning spaces of young children in home environments in Saudi Arabia from mothers’ perspectives. A qualitative research methodology was used. In-depth and semi-structured interviews with 15 mothers of young children (2–5 years old) were conducted. A coding approach was used to analyze the qualitative data, which revealed three themes: (1) direct factors that influence the early literacy learning space at home, (2) indirect factors that influence the early literacy learning space at home, and (3) challenges in creating early literacy learning spaces at home. Several pedagogical implications are suggested at the end of this study that could be useful to parents and caregivers who want to support and improve their children’s early literacy learning spaces.
Reducing Choice-Blindness? An Experimental Study Comparing Experienced Meditators to Non-Meditators
Authors: Lachaud Léa , Jacquet Baptiste , Baratgin Jean
Published: November 2022

The mindfulness trait is an intrinsic characteristic of one’s disposition that facilitates awareness of the present moment. Meditation has proven to enhance situational awareness. In this study, we compared the performance of participants that were split into two groups depending on their experience in mindfulness meditation (a control group naive to mindfulness meditation and a group of experienced mindfulness meditators). Choice-blindness happens when people fail to notice mismatches between their intentions and the consequences of decisions. Our task consisted of decisions where participants chose one preferred female facial image from a pair of images for a total of 15 decisions. By reversing the decisions, unbeknownst to the participants, three discrepancies were introduced in an online experimental design. Our results indicate that the likelihood of detecting one or more manipulations was higher in the mindful group compared to the control group. The higher FMI scores of the mindful group did not contribute to this observation; only the practice of mindfulness meditation itself did. Thus, this could be explained by better introspective access and control of reasoning processes acquired during practice and not by the latent characteristics that are attributed to the mindfulness trait.
The Relationship between Work, Health and Job Performance for a Sustainable Working Life: A Case Study on Older Manual Employees in an Italian Steel Factory
Authors: Previtali Federica , Picco Eleonora , Gragnano Andrea , Miglioretti Massimo
Published: November 2022

Background: Supporting and retaining older workers has become a strategic management goal for companies, considering the ageing of the workforce and the prolongation of working lives. The relationship between health and work is especially crucial for older workers with manual tasks, considering the impact of long-standing health impairments in older age. Although different studies investigated the relationship between work ability and job performance, few studies have analysed the impact of workers’ capability to balance between health and work demands, including managerial and organisational support (work-health balance). Considering health as a dynamic balance between work and health demands influenced by both individual and environmental factors, we assess the mediator role of work-health balance in the relation between work ability and job performance, both self-reported and assessed by the supervisor. Methods: The study utilises data from a case study of 156 manual workers, who were 50 years old or older and employed in a steel company in Italy. Data were collected inside the company as an organiational initiative to support age diversity. Results: The findings show that work-health balance partially mediates the relationship between work ability and self-rated job performance, while it does not mediate the relationship with job performance as rated by the supervisor. Supervisor-rated job performance is positively associated with work ability, while it decreases with the increasing perceived incompatibility between work and health. Conclusion: A perceived balance between health and work is a strategic factor in increasing manual older workers’ job performance. For older workers, not only the perceived capability to work is important but also the organisational health climate and supervisor’s support. More studies are needed to verify if managers overlook the importance of health climate and support, as strategic elements that can foster performance for older employees.
Effect of Temperature and Sliding Velocity on the Dry Sliding Wear Mechanisms of Boron Modified Ti-6Al-4V Alloys
Authors: Dixit Tulika , Prasad K. Eswar
Published: November 2022

The dry sliding wear behavior of as-cast pristine and boron-modified Ti-6Al-4V (Ti64) alloys (having 0.3 and 0.55 wt% B) is investigated using pin-on-disc experiments with the pin being Ti64 alloy and the EN31 steel disc. Experiments are performed at sliding speeds (s) of 1, 2, and 4 m/s and temperatures 300 and 573 K. A mixed response in wear behavior is observed. At the lowest sliding speed, all three alloys (except 0.55B alloy at 300 K) exhibit similar wear rates, with abrasive wear being the dominant wear mechanism. At 2 m/s, temperature and s increase, and adhesive wear takes over along with delamination wear. Here, the 0.55B sample shows the highest wear rate due to the debonding of more TiB particles, which increases three body abrasion wear. With further increase in s to 4 m/s, delamination and oxidation wear are observed for all the samples. XRD evaluation shows traces of TiO2 and Fe2O3, which imply the formation of MML in samples tested at s = 4 m/s, which is also validated through subsurface microstructure analysis. It is found that MML having more TiB particles has more stability, because of which 0.3B samples show higher wear rate.
A Gaussian to Vector Vortex Beam Generator with a Programmable State of Polarization
Authors: Piłka Jacek , Kwaśny Michał , Filipkowski Adam , Buczyński Ryszard , Karpierz Mirosław A. , Laudyn Urszula A.
Published: November 2022

We study an optical device designed for converting the polarized Gaussian beam into an optical vortex of tunable polarization. The proposed device comprised a set of three specially prepared nematic liquid crystal cells and a nano-spherical phase plate fabricated from two types of glass nanotubes. This device generates a high-quality optical vortex possessing one of the multiple polarization states from the uniformly polarized input Gaussian beam. Its small size, simplicity of operation, and electrical steering can be easily integrated into the laboratory and industrial systems, making it a promising alternative to passive vortex retarders and spatial light modulators.
Analysis of Filler Metals Influence on Quality of Hard-Faced Surfaces of Gears Based on Tests in Experimental and Operating Conditions
Authors: Marković Svetislav , Lazić Vukić , Arsić Dušan , Nikolić Ružica R. , Ivković Djordje , Ulewicz Robert , Bokuvka Otakar
Published: November 2022

Hard-facing as a type of the coating depositing is increasingly used today. Physical-chemical-metallurgical characteristics of contact layers in tribo-mechanical systems depend on the operating conditions and the conditions under which the work surfaces were created. That is the reason the influence of the processing procedures and regime, used in the contact surfaces formation, on development of the wear process of contact elements, is being considered ever more. To determine the influence of the hard-facing technology on characteristics of the gears’ working surfaces, the experimental investigations were performed on samples hard-faced on the steel for cementation, by varying the filler metals (FM) and the hard-facing regimes. The samples tested were hard-faced by five “hard” and three “soft” filler metals. Experimental investigations included measuring the hard-faced layers’ hardness and determination of their microstructure, as well as the wear resistance in the laboratory conditions, on tribometer and on a specially designed device for tests in the real operating conditions of gears. The wear intensity was monitored by the wear trace’s width in the laboratory conditions and by the share of the teeth surfaces affected by the destructive pitting in the operating conditions. The results obtained were compared to results of the base metal (BM) tests, which provided the certain conclusions on which filler metal and which welding procedure are the optimal ones for regeneration of the worn teeth surfaces.
Application of Biomineralization Technology to Self-Healing of Fiber-Reinforced Lightweight Concrete after Exposure to High Temperatures
Authors: Chen How-Ji , Chang Hsien-Liang , Tang Chao-Wei , Yang Ting-Yi
Published: November 2022

In the field of civil engineering, concrete self-healing technology plays an important role. Concrete self-healing should be able to effectively heal cracks, not only improving the internal structure, but also improving the mechanical properties and durability of the concrete structure. The biomineralization-repair method is characterized by its potential for long-lasting, rapid, and active crack repair potential. Biomineralization repair has an effective bond ability, is compatible with concrete components, and is also environmentally friendly. This study used biomineralization to explore the self-healing of fiber-reinforced lightweight concrete after its exposure to high temperatures. Concrete specimens of a control group (using lightweight aggregate without bacterial spores and a nutrient source) and an experimental group (using lightweight aggregate containing bacterial spores and a nutrient source) were prepared. The repair effect of the microbial self-healing concrete after the exposure to high temperature was observed by a crack-width gauge, field-emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). According to the EDS and XRD analyses, the precipitate formed at the crack was calcium carbonate. After 28 days of self-healing, the water absorption rate of the experimental group was lower than that of the control group. This is because the specimens of the penetration test were taken from the middle of the concrete cylinder after high temperature, and their bacterial survival rate was higher, which made the mineralization more significant. However, the mechanical test results of the control and experimental groups after the self-healing in the water were not substantially different, which indicated that the bacterial mineralization in the experimental group was slow in the absence of an adequate source of nutrients.
Genetic Algorithm-Assisted Design of Sandwiched One-Dimensional Photonic Crystals for Efficient Fluorescence Enhancement of 3.18-μm-Thick Layer of the Fluorescent Solution
Authors: Song Jiantong , Feng Guang , Liu Xiao , Hou Haoqiang , Chen Zhihui
Published: November 2022

One-dimensional photonic crystal structures have been widely used to enhance fluorescence. However, its fluorescence enhancement is low-fold because of a weak excitation field region. In this paper, we used a genetic algorithm to assist in the design of two photonic crystals based on Al2O3 and TiO2 materials. One of them has a defect consisting of SiO2. The Fabry-Perot cavity (FP cavity) formed by the sandwiched photonic crystal achieves up to 14-fold enhancement of the excitation electric field. We modulate the electric field radiation distribution of the fluorescent material by using photonic forbidden bands. For a 3.18 μm thick layer of the fluorescent solution, the structure achieves up to 60-fold fluorescence enhancement. We also discussed that the reason for the different enhancement abilities in different places is the phase change caused by the optical path difference. This design is expected to have applications in display, imaging, etc.
Impact of Various Catalysts on Transesterification of Used Cooking Oil and Foaming Processes of Polyurethane Systems
Authors: Malewska Elżbieta , Polaczek Krzysztof , Kurańska Maria
Published: November 2022

The search for new sources of raw materials that can be used in the synthesis of polyurethanes and other polymer groups is extremely important. Currently, according to the principles of green chemistry and a circular economy, waste materials with a high reuse potential are being sought. This article presents a way of obtaining used-cooking-oil-based compounds capable of participating in the reaction of polyurethane creation. The transesterification reaction can be carried out using a variety of homo- and heterogeneous acid or base catalysts. Here, we looked at the impact of selected catalysts on the course of transesterification reactions, the composition of the post-reaction mixture and the possibility of using the products in polyurethane foam synthesis. The raw materials and the products were analyzed by means of gel permeation chromatography, FTIR spectroscopy and 1H NMR. The polyurethane foam formation process was analyzed using a FOAMAT® apparatus.
Silane Coatings for Corrosion and Microbiologically Influenced Corrosion Resistance of Mild Steel: A Review
Authors: Al-Saadi Saad , Singh Raman R. K.
Published: November 2022

Mild steel continues to be the most extensively used construction material in several industries and constructions. However, corrosion of mild steel in aggressive environments is a major concern. Under the tremendously increasing demand for improving the coatings strategies because of the environmental concerns due to some of the traditional coatings, silane pre-treatments have been emerging as one of the effective solutions, among other strategies. Different approaches, such as adding particles of metal oxide (such as SiO2, ZrO2, Al2O3, TiO2 and CeO2), incorporating plant extracts and impregnating 2D materials into the coatings, have been employed for durable corrosion resistance, including for mitigating enhanced corrosion due to the presence of bacteria. This review discusses the critical mechanistic features of silane coatings such as the role of hydrolysis and condensation in the bonding of silanes with metal surfaces. The factors that influence the performance of the silane coatings for corrosion resistance of mild steel are discussed. In particular, this review provides insight into silane coatings for mitigating microbiologically influenced corrosion (MIC) of mild steel.
A Magneto-Viscoelasticity Problem with Aging
Authors: Carillo Sandra , Giorgi Claudio
Published: November 2022

This study addresses a magneto-viscoelasticity problem, considering the one-dimensional case. The system under investigation is given by the coupling a non-linear partial differential equation with a linear integro-differential equation. The system models a viscoelastic body whose mechanical behavior, described by the linear integro-differential equation, is also influenced by an external magnetic field. The model here investigated aims to consider the concomitance of three different effects: viscoelasticity, aging and magnetization. In particular, the viscoelastic behavior is represented via an integro-differential equation whose kernel characterizes the properties of the material. In a viscoelastic material subject to the effects of aging, all changes in the response to deformation are due not only to the intrinsic memory of the material but also to deterioration with the age of the material itself. Thus, the relaxation function is not assumed to depend on the two times, present and past, via their difference, but to depend on both the present and past times as two independent variables. The sensibility to an external magnetic field is modeled by a non-linear partial differential equation taking its origin in the Landau–Lifschitz magnetic model. This investigation is part of a long-term research project aiming to provide new insight in the study of materials with memory and, in particular, viscoelastic materials. Specifically, the classical model of viscoelastic body introduced by Boltzmann represents the fundamental base from which a variety of generalizations have been considered in the literature. In particular, the effects on the viscoelastic body due to interaction with an external magnetic field are studied. The new aspect under investigation is the combined presence of the external magnetic field with the effect of aging. Indeed, the coupling of viscoelasticity, which takes into account the deterioration of the material with time, with the presence of an external magnetic field, was never considered in previous research. An existence and uniqueness result is proved under suitable regularity assumptions.
Improved Osseointegration of Selective Laser Melting Titanium Implants with Unique Dual Micro/Nano-Scale Surface Topography
Authors: Sun Xuetong , Lin Huaishu , Zhang Chunyu , Huang Ruiran , Liu Ying , Zhang Gong , Di Si
Published: November 2022

Selective laser melting manufacture of patient specific Ti implants is serving as a promising approach for bone tissue engineering. The success of implantation is governed by effective osseointegration, which depends on the surface properties of implants. To improve the bioactivity and osteogenesis, the universal surface treatment for SLM-Ti implants is to remove the primitive roughness and then reengineer new roughness by various methods. In this study, the micro-sized partially melted Ti particles on the SLM-Ti surface were preserved for assembling mesoporous bioactive glass nanospheres to obtain a unique micro/nano- topography through combination of SLM manufacture and sol–gel processes. The results of simulated body fluid immersion test showed that bioactive ions (Ca, Si) can be continuously and stably released from the MBG nanospheres. The osseointegration properties of SLM-Ti samples, examined using pre-osteoblast cells, showed enhanced adhesion and osteogenic differentiation compared with commercial pure titanium commonly used as orthopedic implants. Overall, the developed approach of construction of the dual micro/nano topography generated on the SLM-Ti native surface could be critical to enhance musculoskeletal implant performance.
In-Situ Growth of Graphene Films to Improve Sensing Performances
Authors: Liu Xinghong , Wu Liang , Yu Xiang , Peng Haoran , Xu Shijue , Zhou Zilong
Published: November 2022

Graphene films made by chemical vapor deposition (CVD) are a popular method to modify sensors by virtue of large-scale and reproducibility, but suffer from various surface contamination and structural defects induced during transfer procedures. In-situ growth of graphene films is proposed in this review article to improve sensing performance. Root causes of the surface contamination and structural defects are revealed with several common transfer methods. In-situ approaches are introduced and compared, growing graphene films with clean surfaces and few defects. This allows graphene film to display superior sensing performance for sensor applications. This work may reasonably be expected to offer a good avenue for synthesis of graphene films applicable for sensing applications.
Performance of an Innovative Low-Cost Recycled Filling (LCRF) in Anaerobic Treatment of Dairy Effluent—A Pilot-Scale Study
Authors: Zieliński Marcin , Dębowski Marcin , Kazimierowicz Joanna
Published: November 2022

The rapid growth in dairy production leads to increasing outputs of high-load effluent, necessitating new methods of treating such waste. Anaerobic processes have been increasingly popular but are hamstrung by limited nutrient removal efficiency. The aim of the present study was to investigate whether low-cost recycled filling (LCRF) improves the anaerobic treatment of dairy effluent. The addition of LCRF was found to increase both COD removal (86.1 ± 2.6%–92.8 ± 1.6%) and Ptot. removal (22.1 ± 3.5% to 36.9 ± 4.6%) from the wastewater. The LCRF ensured near-neutral pH and stabilized the structure of the anaerobic microbe community (including Archaea) across all pollutant loads tested. This translated to efficient biogas production and high methane content in the LCRF reactors, peaking at 0.35 ± 0.01 m3/kg CODremoved and 68.2 ± 0.6% (respectively) in the best-performing variant.
Isotherm, Kinetic, and Selectivity Studies for the Removal of 133Ba and 137Cs from Aqueous Solution Using Turkish Perlite
Authors: İnan Süleyman , Kusumkar Vipul Vilas , Galamboš Michal , Viglašová Eva , Rosskopfová Oľga , Daňo Martin
Published: November 2022

The efficiency of 133Ba and  137Cs removal from aqueous solution is vital to mitigate ecological concerns over spreading these radionuclides in the environment. The present work focused on the use of Turkish perlite for the sorptive removal of  133Ba and  137Cs from aqueous solution by the radioindicator method. Perlite was characterized by XRF, XRD, FTIR, SEM–EDX, and BET analyses. The maximum percentage removals of 88.2% and 78.7% were obtained for  133Ba and  137Cs at pH 6 and pH 9, respectively. For both ions, the sorption equilibrium was attained relatively rapidly. Experimental kinetic data were well described with pseudo-second-order and intraparticle diffusion models. The uptake of both ions increased with the increase in metal concentration (1 × 10−5 to 5 × 10−2 mol/L) in solution. The maximum uptake capacities of  133Ba and  137Cs were found to be 1.96 and 2.11 mmol/g, respectively. The effect of competing ions decreased in the order of Ca2+>K+>Ni2+>Na+ for  133Ba sorption, whereas for  137Cs sorption, the order was determined as Ca2+>Ni2+>K+>Na+. Selectivity studies pointed out that sorption of  133Ba onto perlite is preferable to  137Cs. Therefore, Turkish perlite is a promising, cost-effective, and efficient natural material for the removal of  133Ba and  137Cs from relatively diluted aqueous solution.
Influence of Fabrication Method and Surface Modification of Alumina Ceramic on the Microstructure and Mechanical Properties of Ceramic–Elastomer Interpenetrating Phase Composites (IPCs)
Authors: Kozera Paulina , Boczkowska Anna , Perkowski Krzysztof , Małek Marcin , Kluczyński Janusz
Published: November 2022

The paper presents experimental results of the work conducted to improve the adhesion between alumina ceramics and urea-urethane elastomer in the interpenetrating phase composites (IPCs), in which these two phases are interpenetrating three-dimensionally and topologically throughout the microstructure. Measurements of the contact angle, surface roughness, and shear tests were used to evaluate the effectivity and select the quantity of a silane coupling agent and the ceramic fabrication method. The tests were conducted using samples of dense alumina ceramic obtained by three- or four-step methods. In the four-step process, hot isostatic pressing (HIP) was applied additionally. As a result of the coupling agent coat and HIP application, the ceramic substrate wettability by the elastomer was improved. The water contact angle was reduced from 80 to 60%. In the next step, porous ceramic preforms were fabricated using HIP sintering and a solution of silane coupling agent treated their surface. The composites were produced using vacuum-pressure infiltration of porous alumina ceramics by urea-urethane elastomer in liquid form. The influence of the coupling agent application on the microstructure and mechanical properties of the composites was estimated. The microstructure of the composites was identified using SEM microscopy and X-ray tomography. As a result of using the coupling agent, residual porosity decreased from 7 to 2%, and compressive strength, as well as stress at a plateau, increased by more than 20%, from 25 to 33 MPa and from 15 to 24 MPa, respectively, for the composites fabricated by infiltration ceramic preforms with 40% of porosity.
Efficient Up-Conversion ZnO Co-Doped (Er, Yb) Nanopowders Synthesized via the Sol-Gel Process for Photovoltaic Applications
Authors: Derouiche Marwa , Salhi Rached , Baklouti Samir
Published: November 2022

In this study, undoped and (Erbium, Ytterbium) co-doped ZnO nanopowders were prepared using the sol-gel method and the supercritical drying of ethyl alcohol. Doping ZnO nanopowders were elaborated with 5 mol% of Er (5 Er: ZnO), 5 mol% of Er and 5 mol% of Yb (5 Er, 5 Yb: ZnO), and 5 mol% of Er and 10 mol% of Yb (5 Er, 10 Yb: ZnO) concentrations. The effects of the Yb concentration on the structural, morphological, photoluminescent, and electrical properties of the ZnO nanopowders were investigated. The main findings of this work were the crystallinization of all of the nanopowders in a hexagonal Wurtzite structure with a spheroidal morphology and a size of 60 nm. Hence, the doping concentration would affect the crystallinity and the morphology of the ZnO nanopowder. The UC (Up-Conversion) emissions were investigated under a 980 nm excitation. It was observed that (Er, Yb: ZnO) exhibited green, ranging between 525 nm and 550 nm and red up-converted emissions of 655 nm, due to the efficient energy transfer process between Er3+ and Yb3+. The absolute quantum yield percentage (QY %) of the doped nanopowders was measured as a function of power density at each up-converted emission. This would prove that (5 Er, 5 Yb: ZnO) had the highest QY percentage value of 6.31 ± 0.2% at a power density of 15.7 W/cm2. Additionally, it had the highest excited state lifetime for green and red emissions. Moreover, the Hall effect measures showed that the resistivity decreased while the electron mobility increased after doping, suggesting that most of rare earth ions were located in the interstitial positions. The carrier concentration increased after doping until (5 Er, 5 Yb: ZnO), suggesting that the Zn2+ ions substituted the RE3+ ions. Then, the carrier concentration decreased, suggesting that doping with higher concentrations would cause grain boundary defects. These findings would suggest that (5 Er, 5 Yb: ZnO) would have the best electrical properties and the lowest band gap energy (3.24 eV). Therefore, the presented preparation of the (Er, Yb: ZnO) nanopowders elaborated, using the sol-gel process would be a potential interesting material for UC applications.
Influence of Circular through Hole in Pt–Rh Bushing on Temperature Propagation at High Temperature
Authors: Yang Nan , Gong Youping , He Peng , Zhou Chuanping , Zhou Rougang , Shao Huifeng , Chen Guojin , Lin Xiaowei , Bie Hongling
Published: November 2022

In the fiberglass industry, Pt–Rh bushings made of platinum and rhodium have very good characteristics, such as high temperature resistance, corrosion resistance, oxidation resistance, and creep resistance. In this paper, a semi-infinite lath structure model is constructed, and the expression of the surface temperature distribution of a Pt–Rh alloy plate with a circular through hole is obtained based on the non-Fourier heat conduction equation, complex function method and conformal mapping method. At the same time, the influence of the position of the circular through hole in the Pt–Rh bushing and the parameters of the incident light source (Non-diffusion incident wave number and relative thermal diffusion length) on the surface temperature distribution of the Pt–Rh bushing is studied by using this formula. It is found that: 1. heat concentration and fracture are occur easily at the through hole; 2. when the through hole is in the asymmetric center, the greater the asymmetry, the smaller the maximum temperature amplitude; 3. when the buried depth of the through hole increases, the maximum temperature amplitude decreases; 4. when the incident wave number and the relative thermal diffusion length of the incident light source are larger, the maximum temperature amplitude is smaller. The numerical results are almost consistent with those of ANSYS thermal simulation. The expression of the surface temperature distribution of the semi-infinite lath structure proposed in this paper can effectively reduce the loss of precious metal materials and the time of thermal simulation in the experimental process, as well as provide important significance for structural design, quality inspection, process optimization, and service life improvement of Pt–Rh bushings.
Welding Defect and Mechanical Properties of Nanosecond Laser Cleaning 6005A Aluminum Alloy
Authors: Zhang Yuelai , Yao Qi , Long Weifeng , Wang Chunming , Lin Ji , Liu Zehui
Published: November 2022

Nanosecond laser cleaning effectively removes oxide film and dirt from the surface of aluminum body parts for rail transit, as well as improving surface properties. The effect of laser cleaning on the quality of weld was studied in detail for different scanning frequencies and cleaning speeds. The effect of post-weld laser cleaning on weld quality was investigated. After laser cleaning at different parameters, the surface oxygen content was decreased and the surface roughness and surface hardness were increased. Variation of surface oxygen content was related to energy density and spot density. The lowest oxygen content was obtained at 150 W, 100 Hz and 0.8 m/min. Laser-generated craters changed surface morphology and improved surface roughness. The mechanical properties of the welded joints were slightly improved, which relates to a decrease in porosity. The minimum porosity of the laser-cleaned weld was 0.021%. This work provides new ideas for the nanosecond laser cleaning of aluminum alloy and its welding properties.
Effect of Pro-Ecological Cooling and Lubrication Methods on the Sharpening Process of Planar Blades Used in Food Processing
Authors: Zieliński Bartosz , Nadolny Krzysztof , Zawadka Wojciech , Chaciński Tomasz , Stachurski Wojciech , Batalha Gilmar Ferreira
Published: November 2022

This work presents the results of an experimental study of the sharpening of planar technical blades used in the fish processing industry. Sharpening was carried out in the grinding process using several environmentally friendly methods of cooling and lubricating the machining zone (MQL method, CAG nozzle, hybrid method that is a combination of MQL and CAG methods, as well as WET flooding method as reference). The purpose of the research was to determine the possibility of reducing the negative environmental impact of the sharpening process of technical blades by minimizing the expenditure of coolant. The application of the MQL method and the hybrid MQL + CAG method provided a very good realization of the lubricating function so that the share of friction of dulled cutting vertices against the workpiece surface is reduced, which manifests itself in the reduction of the grinding force and the correlated grinding power. In the case of grinding under cooled compressed air delivery conditions, the average cutting force was as much as 91.6% higher (F = 22.63 N) compared to the result obtained for the most favorable flooding method, demonstrating the insufficient quality of the blade shaped under such conditions. A comprehensive comparison of test results on grinding power gain, cutting force and surface texture suggests that the most favorable sharpening results were obtained using the environmentally friendly MQL method of cooling and lubricating the grinding zone.
A Control Strategy of LCL-Type Grid-Connected Inverters for Improving the Stability and Harmonic Suppression Capability
Authors: Wang Xian , Wang Dazhi , Zhou Shuai
Published: November 2022

The conventional inverter-side current single-loop feedback control scheme is weak in suppressing the grid-side current harmonics, posing a challenge for an inverter to inject high-quality current under distorted grid voltage. With capacitor current compensation added, the control scheme achieves controllability of the grid-side current harmonics so that it can effectively suppress some specific harmonic components. However, due to the stability requirements, only a few low-order harmonic resonance controllers can be applied, which limits the mitigation of high-order harmonics. To tackle this problem, the grid-side current feedback control with inductor–capacitor–inductor (LCL) resonance damping is proposed in this paper. In this case, a higher LCL resonance frequency can be set compared to the inverter-side current single-loop feedback control scheme. Thereby, more resonance controllers can be applied to suppress high-order grid-side current harmonics. The active damping method of capacitor current proportional feedback plus capacitor voltage proportional feedback is adopted because of its high robustness to grid impedance variations. Furthermore, this paper reveals that the applied active damping method has a limitation in that it only considers a single inverter under inductive grid impedance, which cannot eliminate the risk of resonance caused by the interaction of multiple inverters and the grid. To address this issue, a phase lead compensator (PLC) is proposed, eliminating the resonance risk by removing the non-passive region of the inverter output admittance. To retain the advantage of the inverter-side current single-loop feedback control scheme, i.e., only a few measuring devices are required, a digital differentiator is used to calculate the capacitor current from the capacitor voltage. The difference between the measured inverter-side current and the calculated capacitor current is taken to approximate the grid-side current for the feedback control. The control performance is comparable to using the grid-side current for feedback. Simulation and experimental results demonstrate that the proposed control scheme endows the inverter with good stability and current quality without extra measurement devices.
Air Combat Maneuver Decision Method Based on A3C Deep Reinforcement Learning
Authors: Fan Zihao , Xu Yang , Kang Yuhang , Luo Delin
Published: November 2022

To solve the maneuvering decision problem in air combat of unmanned combat aircraft vehicles (UCAVs), in this paper, an autonomous maneuver decision method is proposed for a UCAV based on deep reinforcement learning. Firstly, the UCAV flight maneuver model and maneuver library of both opposing sides are established. Then, considering the different state transition effects of various actions when the pitch angles of the UCAVs are different, the 10 state variables including the pitch angle, are taken as the state space. Combined with the air combat situation threat assessment index model, a two-layer reward mechanism combining internal reward and sparse reward is designed as the evaluation basis of reinforcement learning. Then, the neural network model of the full connection layer is built according to an Asynchronous Advantage Actor–Critic (A3C) algorithm. In the way of multi-threading, our UCAV keeps interactively learning with the environment to train the model and gradually learns the optimal air combat maneuver countermeasure strategy, and guides our UCAV to conduct action selection. The algorithm reduces the correlation between samples through multi-threading asynchronous learning. Finally, the effectiveness and feasibility of the method are verified in three different air combat scenarios.