bluuebunny/crossref_metadata_2025 huggingface dataset:
Intensive Care Patients from the First COVID-19 Wave: One-Year Survival after Tocilizumab Treatment
Authors: Melegari Gabriele , Giuliani Enrico , Dallai Chiara , Veronesi Lucia , Bertellini Elisabetta , Osmenaj Suela , Barbieri Alberto
Published: November 2021

Introduction: An infection by COVID-19 triggers a dangerous cytokine storm, so tocilizumab has been introduced in Italy as an agent blocking the cytokine storm. This paper aims to describe the one-year survival of ICU patients treated with tocilizumab. Methods: This observational study enrolled all patients confirmed to be infected by COVID-19 who were admitted to the ICU in our center. We offered tocilizumab to all non-septic patients if they did not present any contraindications. Results: We enrolled 68 ICU patients in our center on 72 occasions during the enrollment period; we excluded four patients due to study criteria. The one-year mortality hazard ratio of treated patients was 0.64, with a confidence interval of 0.31 to 1.19, with p = 0.169. Among the survivors, 32 of 35 patients answered the phone interview (14 patients in the treated group and 18 in the untreated group); overall, the effect of COVID-19 on quality of life was 58.14%. These effects were lower in the tocilizumab group, with p = 0.016 *. Conclusions: Our observational data follow the most relevant largest trial. Patients treated with tocilizumab had lower rates of new-onset symptoms later COVID-19 ICU hospitalizations. As reported by recent medical literature, the presence of these symptoms suggests that a follow-up program for these types of patients could be useful.
Community Perceptions about Participating in Urban Park Establishment in Ulaanbaatar City, Mongolia
Authors: Enkhbold Bayarmaa , Matsui Kenichi
Published: November 2021

Urban parks are essential for communities to maintain and improve health, culture, and quality of life. However, Ulaanbaatar, the capital of Mongolia, faces a shortage of urban parks due to overpopulation and unplanned land use. A good community-based strategy can help urban park planners and decision-makers understand residents’ needs. It can also improve livability and the urban environmental conditions at large. This paper attempts to understand residents’ perceptions about participating in urban park establishment and maintenance. As the past studies showed a lack of community participation in urban planning in Ulaanbaatar, it attempts to determine the extent to which residents perceive urban park benefits, the importance of community participation, preferred types of contribution, and willingness to contribution land in establishing urban parks in their neighborhood. In doing so, it identifies socio-demographic factors that influence their willingness to participate and contribute. A total of 600 paper-based questionnaires were randomly distributed among ger and apartment residents, and only 535 were analyzed. The result shows that approximately 73% of the respondents considered community participation very important for establishing urban parks in their neighborhood. Most respondents perceived urban park benefits as playgrounds for children, and relaxation and recreation. Respondents’ education and housing type were found significant in overall willingness to participate in park establishment and maintenance, whereas marital status and land size were observed statistically significant in the willingness of sharing some portions of their lands for park establishment in the ger area.
Challenges for European Tourist-City-Ports: Strategies for a Sustainable Coexistence in the Cruise Post-COVID Context
Authors: Andrade María J. , Costa João Pedro , Jiménez-Morales Eduardo
Published: November 2021

In recent years, cruise tourism has increased the negative effects caused by touristification in many European port cities. Despite this, these cities are in a great competition to be a destination, a tourist-port. Cruise tourism has come to stay, and a steady growth can be expected in a post-COVID-19 scenario, but at what cost? The tourist-port demands highly effective planning answers occurring simultaneously, and the global pandemic crisis provides a buffer of time to seek best practices, combining the expected economical (re)development with social, environmental, and cultural sustainability. This paper proposes five different strategies that contribute to finding a sustainable coexistence between tourist ports and their cities. To this end, trans-scalar strategies developed in previous research from different disciplines have been studied and categorized in a port-city context, in order to provide a holistic viewpoint on the measures carried out to maximize the benefits and limit the negative impacts of cruise tourism on cities.
Agrivoltaics: A Climate-Smart Agriculture Approach for Indian Farmers
Authors: Mahto Rakeshkumar , Sharma Deepak , John Reshma , Putcha Chandrasekhar
Published: November 2021

India is a leader when it comes to agriculture. A significant part of the country’s population depends on agriculture for livelihood. However, many of them face challenges due to using unreliable farming techniques. Sometimes the challenges increase to the extent that they commit suicide. Besides, India is highly populated, and its population is steadily increasing, requiring its government to grow its GDP and increase its energy supply proportionately. This paper reviews integrating solar farming with agriculture, known as Agrivoltaics, as a Climate-Smart Agriculture (CSA) option for Indian farmers. This study is further supported by the Strength, Weaknesses, Opportunities, and Threats (SWOT) analysis of agrivoltaics. Using the SWOT analysis, this article presents how agrivoltaics can make agriculture sustainable and reliable. This paper identifies rural electrification, water conservation, yield improvement, sustainable income generation, and reduction in the usage of pesticides as the strengths of agrivoltaics. Similarly, the paper presents weaknesses, opportunities, and threats to agrivoltaics in India. The research concludes with the findings that agrivoltaics have the potential of meeting multiple objectives such as meeting global commitments, offering employment, providing economic stability, increasing clean energy production capacity, conserving natural resources, and succeeding in several others. The paper also includes a discussion about the findings, suggestions, and implications of adopting agrivoltaics on a large scale in India.
Association of Contemporary Statin Pretreatment Intensity and LDL-C Levels on the Incidence of STEMI Presentation
Authors: Dadon Ziv , Moriel Mady , Iakobishvili Zaza , Asher Elad , Samuel Tal Y. , Gavish Dov , Glikson Michael , Gottlieb Shmuel
Published: November 2021

Constituting hypolipidemic and pleiotropic effects, statins stabilize coronary artery plaque and may prevent STEMI events. This study investigated the association between contemporary statin pretreatment intensity, low-density lipoprotein cholesterol (LDL-C) levels, and the type of acute coronary syndrome (ACS) presentation: STEMI vs. NSTE-ACS. Data were drawn from the ACS Israeli Survey (ACSIS), a biennial prospective national survey that took place in 2008–2018. The rate of STEMI vs. NSTE-ACS was calculated by statin use, including statin intensity (high-intensity statin therapy (HIST) and low-intensity statin therapy (LIST) prior to the index ACS event. Among 5103 patients, 2839 (56%) were statin-naive, 1389 (27%) used LIST and 875 (17%) used HIST. Statin pretreated patients were older and had a higher rates of co-morbidities, cardiovascular disease history and pretreatment with evidence-based medications. STEMI vs. NSTE-ACS was lower among HIST vs. LIST vs. statin-naive patients (31.0%, 37.8%, and 54.0%, respectively, p for trend < 0.001). Multivariate analysis revealed that HIST was independently associated with lower STEMI presentation (ORadj 0.70; 95% CI 0.57–0.86), while LIST (ORadj 0.92; 95% CI 0.77–1.10) and LDL-C < 70 mg/dL (ORadj 0.96; 95% CI 0.82–1.14) were not. In conclusion, among patients admitted with ACS, pretreatment with HIST was independently associated with a lower probability of STEMI presentation, while LIST and LDL-C < 70 mg/dL were not.
Oxidative Stress, Mitochondrial Function and Adaptation to Exercise: New Perspectives in Nutrition
Authors: Vargas-Mendoza Nancy , Angeles-Valencia Marcelo , Morales-González Ángel , Madrigal-Santillán Eduardo Osiris , Morales-Martínez Mauricio , Madrigal-Bujaidar Eduardo , Álvarez-González Isela , Gutiérrez-Salinas José , Esquivel-Chirino César , Chamorro-Cevallos Germán , Cristóbal-Luna José Melesio , Morales-González José A.
Published: November 2021

Cells have the ability to adapt to stressful environments as a part of their evolution. Physical exercise induces an increase of a demand for energy that must be met by mitochondria as the main (ATP) provider. However, this process leads to the increase of free radicals and the so-called reactive oxygen species (ROS), which are necessary for the maintenance of cell signaling and homeostasis. In addition, mitochondrial biogenesis is influenced by exercise in continuous crosstalk between the mitochondria and the nuclear genome. Excessive workloads may induce severe mitochondrial stress, resulting in oxidative damage. In this regard, the objective of this work was to provide a general overview of the molecular mechanisms involved in mitochondrial adaptation during exercise and to understand if some nutrients such as antioxidants may be implicated in blunt adaptation and/or an impact on the performance of exercise by different means.
Ovarian Malignancies Frequency in the Female Population from the Bryansk Region Living in Conditions of Radioactive, Chemical and Combine Contamination (2000–2020)
Authors: Korsakov Anton V. , Golovleva Alexandra A. , Troshin Vladislav P. , Lagerev Dmitry G. , Pugach Leonid I.
Published: November 2021

Background: Radioactive contamination and chemical pollution of the environment can affect the processes of carcinogenesis, including the formation of malignant neoplasms of the ovaries in women. We used the data of official state statistics for 2000–2020 to test the hypothesis about the effect of radioactive contamination (following the Chernobyl disaster) and chemical pollutants on the incidence of ovarian malignancies in the female population of the Bryansk region. Methods: A variety of statistical approaches were used to estimate the incidence of ovarian malignancies, including the Shapiro–Wilk test, Mann–Whitney U test, Spearman’s rank correlation test and linear regression. Results: We did not establish statistically significant differences in the frequency of primary morbidity of women with malignant neoplasms of the ovaries, regardless of the environmental conditions of living. Furthermore, no significant correlations were found between the frequency of primary morbidity of ovarian malignancies, both with the level of contamination by Cesium-137 and Strontium-90, and air pollution with volatile organic compounds, carbon monoxide, sulfur dioxide and nitrogen oxides. A statistically significant increase in the long-term trend in the frequency of ovarian malignant neoplasms was revealed in the areas of chemical pollution (p = 0.02), however, in other territories, no statistically significant regularities were established. The forecast of the frequency of newly diagnosed malignant neoplasms of the ovaries on average in the Bryansk region shows an increase of 12.4% in 2020 in comparison with the real data for 2020, while the largest increase in predicted values is recorded in the territories of radioactive contamination (by 79.6%), and the least in the combined territories (by 6.9%). Conclusions: The results obtained indicate the need for further work to understand the trends in the presence/absence of independent and combined effects of pollutants and the growth of oncogynecological pathology from the perspective of assessing the distant and regional metastasis, histological and immunohistochemical profile of a specific malignant ovarian neoplasm with levels of environmental contamination.
A Potential Serum Biomarker for Screening Lung Cancer Risk in High Level Environmental Radon Areas: A Pilot Study
Authors: Autsavapromporn Narongchai , Klunklin Pitchayaponne , Chitapanarux Imjai , Jaikang Churdsak , Chewaskulyong Busyamas , Sripan Patumrat , Hosoda Masahiro , Tokonami Shinji
Published: November 2021

Radon is a major cause of lung cancer (LC) deaths among non-smokers worldwide. However, no serum biomarker for screening of LC risk in high residential radon (HRR) areas is available. Therefore, the aim of this study was to determine diagnostic values of serum carcinoembryonic antigen (CEA), cytokeratin 19 fragment (Cyfra21-1), human epididymis protein 4 (HE4), interleukin 8 (IL-8), migration inhibitory factor (MIF), tumor nuclear factor-alpha (TNF-α) and vascular endothelial growth factors (VEGF) occurring in high radon areas. Seventy-five LC non-smoker patients and seventy-five healthy controls (HC) were enrolled in this study. Among the HC groups, twenty-five HC were low residential radon (LRR) and fifty HC were HRR. Significantly higher (p < 0.0004) serum levels of CEA, Cyfra21-1, IL-8 and VEGF were found in the LC compared with the LRR and HRR groups. More importantly, significantly higher levels (p < 0.009) of serum CEA, Cyfra21-1 and IL-8 were observed in HRR compared with the LRR group. Likewise, a ROC curve demonstrated that serum CEA and Cyfra21-1 could better distinguish LC risk from HRR groups than IL-8. These results indicated that serum CEA and Cyfra21-1 were significantly increased in the HRR group and may be considered as potential biomarkers for individuals at high-risk to develop LC.
Special Issue “Reproductive Health Concerns for Women”
Authors: Yang Szu-Ting , Lee Wen-Ling , Wang Peng-Hui
Published: November 2021

There are specific health issues concerning the reproductive age of women, including inflammatory disease, fertility, and childbearing [...]
The Interplay of Nutriepigenomics, Personalized Nutrition and Clinical Practice in Managing Food Allergy
Authors: Ali Adli , Hamzaid Nur Hana , Ismail Noor Akmal Shareela
Published: November 2021

Food allergy in children has been a common issue due to the challenges of prescribing personalized nutrition with a lack of nutriepigenomics data. This has indeed further influenced clinical practice for appropriate management. While allergen avoidance is still the main principle in food allergy management, we require more information to advance the science behind nutrition, genes, and the immune system. Many researchers have highlighted the importance of personalized nutrition but there is a lack of data on how the decision is made. Thus, this review highlights the relationship among these key players in identifying the solution to the clinical management of food allergy with current nutriepigenomics data. The discussion integrates various inputs, including clinical assessments, biomarkers, and epigenetic information pertaining to food allergy, to curate a holistic and personalized approach to food allergy management in particular.
The Influence of Loop Heat Pipe Evaporator Porous Structure Parameters and Charge on Its Effectiveness for Ethanol and Water as Working Fluids
Authors: Blauciak Krzysztof , Szymanski Pawel , Mikielewicz Dariusz
Published: November 2021

This paper presents the results of experiments carried out on a specially designed experimental rig designed for the study of capillary pressure generated in the Loop Heat Pipe (LHP) evaporator. The commercially available porous structure made of sintered stainless steel constitutes the wick. Three different geometries of the porous wicks were tested, featuring the pore radius of 1, 3 and 7 µm. Ethanol and water as two different working fluids were tested at three different evaporator temperatures and three different installation charges. The paper firstly presents distributions of generated pressure in the LHP, indicating that the capillary pressure difference is generated in the porous structure. When installing with a wick that has a pore size of 1 μm and water as a working fluid, the pressure difference can reach up to 2.5 kPa at the installation charge of 65 mL. When installing with a wick that has a pore size of 1 μm and ethanol as a working fluid, the pressure difference can reach up to 2.1 kPa at the installation charge of 65 mL. The integral characteristics of the LHP were developed, namely, the mass flow rate vs. applied heat flux for both fluids. The results show that water offers larger pressure differences for developing the capillary pressure effect in the installation in comparison to ethanol. Additionally, this research presents the feasibility of manufacturing inexpensive LHPs with filter medium as a wick material and its influence on the LHP’s thermal performance.
Notes on the Abrasive Water Jet (AWJ) Machining
Authors: Gembalová Lucie , Hlaváč Libor M. , Spadło Sławomir , Geryk Vladan , Oros Luka
Published: November 2021

The aim of the research was to investigate changes of abrasive grains on metals observing the kerf walls produced by the Abrasive Water Jet (AWJ). The microscopy observations of the sidewalls of kerfs cut by the AWJ in several metal materials with an identical thickness of 10 mm are presented. The observed sizes of abrasive grains were compared with the results of research aimed at the disintegration of the abrasive grains during the mixing process in the cutting head during the injection AWJ creation. Some correlations were discovered and verified. The kerf walls observations show the size of material disintegration caused by the individual abrasive grains and also indicate the size of these grains. One part of this short communication is devoted to a critical look at some of the conclusions of the older published studies, namely regarding the correlation of the number of interacting particles with the acoustic emissions measured on cut materials. The discussion is aimed at the abrasive grain size after the mixing process and changes of this size in the interaction with the target material.
Quartz Tuning Fork Sensor-Based Dosimetry for Sensitive Detection of Gamma Radiation
Authors: Alanazi Nadyah , Alodhayb Abdullah N. , Almutairi Atheer , Alshehri Hanan , AlYemni Sarah , Alsowygh Ghadah , Abdulmawla Sabaa , Shamma Khaled , Albrithen Hamad , Muthuramamoorthy Muthumareeswaran , Almuqrin Aljawhara H.
Published: November 2021

This study generally relates to nuclear sensors and specifically to detecting nuclear and electromagnetic radiation using an ultrasensitive quartz tuning fork (QTF) sensor. We aim to detect low doses of gamma radiation with fast response time using QTF. Three different types of QTFs (uncoated and gold coated) were used in this study in order to investigate their sensitivity to gamma radiations. Our results show that a thick gold coating on QTF can enhance the quality factor and increase the resonance frequency from 32.7 to 32.9 kHz as compared to uncoated QTF. The results also show that increasing the surface area of the gold coating on the QTF can significantly enhance the sensitivity of the QTF to radiation. We investigated the properties of gold-coated and uncoated QTFs before and after irradiation by scanning electron microscopy. We further investigated the optical properties of SiO2 wafers (quartz) by spectroscopic ellipsometry (SE). The SE studies revealed that even a small change in the microstructure of the material caused by gamma radiation would have an impact on mechanical properties of QTF, resulting in a shift in resonance frequency. Overall, the results of the experiments demonstrated the feasibility of using QTF sensors as an easy to use, low-cost, and sensitive radiation detector.
Removal of Heavy Metal Ions from One- and Two-Component Solutions via Adsorption on N-Doped Activated Carbon
Authors: Kazmierczak-Razna Justyna , Zioła-Frankowska Anetta , Nowicki Piotr , Frankowski Marcin , Wolski Robert , Pietrzak Robert
Published: November 2021

This paper deals with the adsorption of heavy metal ions (Cu2+ and Zn2+) on the carbonaceous materials obtained by chemical activation and ammoxidation of Polish brown coal. The effects of phase contact time, initial metal ion concentration, solution pH, and temperature, as well as the presence of competitive ions in solution, on the adsorption capacity of activated carbons were examined. It has been shown that the sample modified by introduction of nitrogen functional groups into carbon structure exhibits a greater ability to uptake heavy metals than unmodified activated carbon. It has also been found that the adsorption capacity increases with the increasing initial concentration of the solution and the phase contact time. The maximum adsorption was found at pH = 8.0 for Cu(II) and pH = 6.0 for Zn(II). For all samples, better fit to the experimental data was obtained with a Langmuir isotherm than a Freundlich one. A better fit of the kinetic data was achieved using the pseudo-second order model.
Wear Behavior of a Heat-Treatable Al-3.5Cu-1.5Mg-1Si Alloy Manufactured by Selective Laser Melting
Authors: Wang Pei , Lei Yang , Qi Jun-Fang , Yu Si-Jie , Setchi Rossitza , Wu Ming-Wei , Eckert Jürgen , Li Hai-Chao , Scudino Sergio
Published: November 2021

In this study, the wear behavior of a heat-treatable Al-7Si-0.5Mg-0.5Cu alloy fabricated by selective laser melting was investigated systematically. Compared with the commercial homogenized AA2024 alloy, the fine secondary phase of the SLM Al-Cu-Mg-Si alloy leads to a low specific wear rate (1.8 ± 0.11 × 10−4 mm3(Nm)−1) and a low average coefficient of friction (0.40 ± 0.01). After the T6 heat treatment, the SLM Al-Cu-Mg-Si alloy exhibits a lower specific wear rate (1.48 ± 0.02 × 10−4 mm3(Nm)−1), but a similar average coefficient of friction (0.34 ± 0.01) as the heat-treated AA2024 alloy. Altogether, the SLM Al-3.5Cu-1.5Mg-1Si alloy is suitable for the achievement of not only superior mechanical performance, but also improved tribological properties.
Analysis of Selected Properties of Injection Moulded Sustainable Biocomposites from Poly(butylene succinate) and Wheat Bran
Authors: Sasimowski Emil , Majewski Łukasz , Grochowicz Marta
Published: November 2021

The paper presents a procedure of the manufacturing and complex analysis of the properties of injection mouldings made of polymeric composites based on the poly(butylene succinate) (PBS) matrix with the addition of a natural filler in the form of wheat bran (WB). The scope of the research included measurements of processing shrinkage and density, analysis of the chemical structure, measurements of the thermal and thermo-mechanical properties (Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TG), Heat Deflection Temperature (HDT), and Vicat Softening Temperature (VST)), and measurements of the mechanical properties (hardness, impact strength, and static tensile test). The measurements were performed using design of experiment (DOE) methods, which made it possible to determine the investigated relationships in the form of polynomials and response surfaces. The mass content of the filler and the extruder screw speed during the production of the biocomposite granulate, which was used for the injection moulding of the test samples, constituted the variable factors adopted in the DOE. The study showed significant differences in the processing, thermal, and mechanical properties studied for individual systems of the DOE.
Carbonized Solid Fuel Production from Polylactic Acid and Paper Waste Due to Torrefaction
Authors: Świechowski Kacper , Zafiu Christian , Białowiec Andrzej
Published: November 2021

The quantity of biodegradable plastics is increasing steadily and taking a larger share in the residual waste stream. As the calorific value of biodegradable plastic is almost two-fold lower than that of conventional ones, its increasing quantity decreases the overall calorific value of municipal solid waste and refuse-derived fuel which is used as feedstock for cement and incineration plants. For that reason, in this work, the torrefaction of biodegradable waste, polylactic acid (PLA), and paper was performed for carbonized solid fuel (CSF) production. In this work, we determined the process yields, fuel properties, process kinetics, theoretical energy, and mass balance. We show that the calorific value of PLA cannot be improved by torrefaction, and that the process cannot be self-sufficient, while the calorific value of paper can be improved up to 10% by the same process. Moreover, the thermogravimetric analysis revealed that PLA decomposes in one stage at ~290–400 °C with a maximum peak at 367 °C, following a 0.42 reaction order with the activation energy of 160.05 kJ·(mol·K)−1.
Grain Size Influence on the Magnetic Property Deterioration of Blanked Non-Oriented Electrical Steels
Authors: Boehm Lucas , Hartmann Christoph , Gilch Ines , Stoecker Anett , Kawalla Rudolf , Wei Xuefei , Hirt Gerhard , Heller Martin , Korte-Kerzel Sandra , Leuning Nora , Hameyer Kay , Volk Wolfram
Published: November 2021

Non-oriented electrical steel sheets are applied as a core material in rotors and stators of electric machines in order to guide and magnify their magnetic flux density. Their contouring is often realized in a blanking process step, which results in plastic deformation of the cut edges and thus deteriorates the magnetic properties of the base material. This work evaluates the influence of the material’s grain size on its iron losses after the blanking process. Samples for the single sheet test were blanked at different cutting clearances (15 µm–70 µm) from sheets with identical chemical composition (3.2 wt.% Si) but varying average grain size (28 µm–210 µm) and thickness (0.25 mm and 0.5 mm). Additionally, in situ measurements of blanking force and punch travel were carried out. Results show that blanking-related iron losses either increase for 0.25 mm thick sheets or decrease for 0.5 mm thick sheets with increasing grain size. Although this is partly in contradiction to previous research, it can be explained by the interplay of dislocation annihilation and transgranular fracturing. The paper thus contributes to a deeper understanding of the blanking process of coarse-grained, thin electrical steel sheets.
Synthesis of High-Performance CSA Cements as Low Carbon OPC Alternative
Authors: Marin Bogdan-Catalin , Voicu Georgeta , Stoleriu Stefania
Published: November 2021

Starting from natural raw materials, cements based calcium sulphoaluminate (CSA) clinkers have been successfully obtained as an eco-friendly alternative to ordinary Portland cement. CSA-based cements with ye’elimite as the main phase have been produced over the years and are widely used today. In this regard, the present paper considers the study of hydration processes for CSA pastes prepared with a water/cement ratio of 0.5 according to the EN-197 standard and their characterization by thermal analysis (DTA-TG), X-ray diffraction analysis (XRD), and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX). A mechanical strength of 60.9 MPa was the greatest achieved for mortars hardened for 28 days.
Brewed Robusta Coffee Increases Nickel Ion Release from Dental Alloys: An In Vitro Study
Authors: Rachmawati Dessy , Cahyasari Devanti Ayu , Febiantama Ardin Tito , Hidayati Lusi , Kleverlaan Cornelis Johannes
Published: November 2021

Alloys in oral cavity always interact with dynamic oral environment, such as pH, temperature, salivary conditions, and dietary habits. Coffee can further decrease pH in the oral cavity. Thus, coffee may increase the release of metal ions that may lead to various health diseases. This study aimed to quantitively investigate the effect of brewed Robusta coffee on the nickel ion release and their morphological structures; Methods: 20 alloy specimens were divided into 4 groups and placed in solutions for 48 and 168 h: (1) distilled water, (2) artificial saliva, (3) Robusta coffee, and (4) mixture of artificial saliva and Robusta coffee. AAS, XRF, and SEM were used for examinations; Results: The release of Ni2+ was found in all groups and robust release were found in the coffee only and mixture of coffee + artificial saliva solution after 168 h. Likewise, SEM showed that internal oxidation was high after 168 h of immersion; Conclusions: The concentration of nickel increased in saliva of low pH due to brewed coffee. Though the release of these ions is still within the tolerable amount in human body, it should be realized that it usually lasts for months or years. Dentists should be cautious when using instructions for patients with a history of allergies especially for dietary with low acidity.
Thermal Deformations of Thermoplast during 3D Printing: Warping in the Case of ABS
Authors: Ramian Jakub , Ramian Jan , Dziob Daniel
Published: November 2021

This research focuses on thermal deformations of thermoplast during three-dimensional printing. A filament acrylonitrile butadiene styrene was used, and the main focus was put on warping. Twenty-seven cuboids divided in six categories by their length, height, surface area, color, nozzle temperature and bed temperature were printed by Fused Filament Fabrication 3D printer. The whole process was captured by a thermal camera and the movies were used to analyze the temperature distribution during printing. All printouts were measured and scanned with a 3D scanner in order to highlight any abbreviations from the original digital models. The obtained results were used to formulate some general conclusions on the influence of selected parameters on the warping process. Based on the outcomes of the study, a set of guidelines on how to minimalize warping was proposed.
Palm Oil Fuel Ash-Based Eco-Friendly Concrete Composite: A Critical Review of the Long-Term Properties
Authors: Amran Mugahed , Lee Yeong Huei , Fediuk Roman , Murali Gunasekaran , Mosaberpanah Mohammad Ali , Ozbakkaloglu Togay , Yong Lee Yee , Vatin Nikolai , Klyuev Sergey , Karelia Maria
Published: November 2021

Rapid global infrastructural developments and advanced material science, amongst other factors, have escalated the demand for concrete. Cement, which is an integral part of concrete, binds the various individual solid materials to form a cohesive mass. Its production to a large extent emits many tons of greenhouse gases, with nearly 10% of global carbon (IV) oxide (CO2) emanating from cement production. This, coupled with an increase in the advocacy for environmental sustainability, has led to the development of various innovative solutions and supplementary cementitious materials. These aims to substantially reduce the overall volume of cement required in concrete and to meet the consistently increasing demand for concrete, which is projected to increase as a result of rapid construction and infrastructural development trends. Palm oil fuel ash (POFA), an industrial byproduct that is a result of the incineration of palm oil wastes due to electrical generation in power plants has unique properties, as it is a very reactive materials with robust pozzolanic tendencies, and which exhibits adequate micro-filling capabilities. In this study, a review on the material sources, affecting factors, and durability characteristics of POFA are carefully appraised. Moreover, in this study, a review of correlated literature with a broad spectrum of insights into the likely utilization of POFA-based eco-friendly concrete composites as a green material for the present construction of modern buildings is presented.
An Approach to the Study of a 19th-Century Sugarcane Mill and Steam Engine through CAD Techniques and Mechanical Engineering
Authors: Rojas-Sola José Ignacio , Río-Cidoncha Gloria del , Ortíz-Marín Rafael , Trenas-Arbizu Justino
Published: November 2021

This article shows an approach to the three-dimensional modelling of a sugarcane mill and its associated steam engine, designed by the Robey and Co. engineering company in 1869. In order to obtain the 3D CAD model of said invention, CATIA V5 R20 software has been employed. Various sources of starting material, from the basis of this research and found in the process of searching for relevant information, provide information on the main elements, operating conditions, and mechanism of the machine. Thanks to the three-dimensional geometric modelling carried out, it has been possible to explain, in detail, both its operation and the final assembly of the invention through the assemblies of its different subsets, thereby obtaining a virtual recreation that shows its operation. Likewise, a study has been carried out, from a mechanical engineering viewpoint, of the gear train that transmitted the movement, in order to ascertain the compression force exerted on the sugar cane. This research, related to industrial archaeology, therefore, enables the reader to understand a machine that constituted a milestone in the sugarcane industry, while paying tribute to the English engineer, Robert Robey.
Assessment of Dynamic Bayesian Models for Gas Turbine Diagnostics, Part 1: Prior Probability Analysis
Authors: Zaccaria Valentina , Fentaye Amare Desalegn , Kyprianidis Konstantinos
Published: November 2021

The reliability and cost-effectiveness of energy conversion in gas turbine systems are strongly dependent on an accurate diagnosis of possible process and sensor anomalies. Because data collected from a gas turbine system for diagnosis are inherently uncertain due to measurement noise and errors, probabilistic methods offer a promising tool for this problem. In particular, dynamic Bayesian networks present numerous advantages. In this work, two Bayesian networks were developed for compressor fouling and turbine erosion diagnostics. Different prior probability distributions were compared to determine the benefits of a dynamic, first-order hierarchical Markov model over a static prior probability and one dependent only on time. The influence of data uncertainty and scatter was analyzed by testing the diagnostics models on simulated fleet data. It was shown that the condition-based hierarchical model resulted in the best accuracy, and the benefit was more significant for data with higher overlap between states (i.e., for compressor fouling). The improvement with the proposed dynamic Bayesian network was 8 percentage points (in classification accuracy) for compressor fouling and 5 points for turbine erosion compared with the static network.
Fast Hyperparameter Calibration of Sparsity Enforcing Penalties in Total Generalised Variation Penalised Reconstruction Methods for XCT Using a Planted Virtual Reference Image
Authors: Chrétien Stéphane , Giampiccolo Camille , Sun Wenjuan , Talbott Jessica
Published: November 2021

The reconstruction problem in X-ray computed tomography (XCT) is notoriously difficult in the case where only a small number of measurements are made. Based on the recently discovered Compressed Sensing paradigm, many methods have been proposed in order to address the reconstruction problem by leveraging inherent sparsity of the object’s decompositions in various appropriate bases or dictionaries. In practice, reconstruction is usually achieved by incorporating weighted sparsity enforcing penalisation functionals into the least-squares objective of the associated optimisation problem. One such penalisation functional is the Total Variation (TV) norm, which has been successfully employed since the early days of Compressed Sensing. Total Generalised Variation (TGV) is a recent improvement of this approach. One of the main advantages of such penalisation based approaches is that the resulting optimisation problem is convex and as such, cannot be affected by the possible existence of spurious solutions. Using the TGV penalisation nevertheless comes with the drawback of having to tune the two hyperparameters governing the TGV semi-norms. In this short note, we provide a simple and efficient recipe for fast hyperparameters tuning, based on the simple idea of virtually planting a mock image into the model. The proposed trick potentially applies to all linear inverse problems under the assumption that relevant prior information is available about the sought for solution, whilst being very different from the Bayesian method.
On the State Approach Representations of Convolutional Codes over Rings of Modular Integers
Authors: Muñoz Castañeda Ángel Luis , DeCastro-García Noemí , Carriegos Miguel V.
Published: November 2021

In this study, we prove the existence of minimal first-order representations for convolutional codes with the predictable degree property over principal ideal artinian rings. Further, we prove that any such first-order representation leads to an input/state/output representation of the code provided the base ring is local. When the base ring is a finite field, we recover the classical construction, studied in depth by J. Rosenthal and E. V. York. This allows us to construct observable convolutional codes over such rings in the same way as is carried out in classical convolutional coding theory. Furthermore, we prove the minimality of the obtained representations. This completes the study of the existence of input/state/output representations of convolutional codes over rings of modular integers.
Rockburst Interpretation by a Data-Driven Approach: A Comparative Study
Authors: Sun Yuantian , Li Guichen , Yang Sen
Published: November 2021

Accurately evaluating rockburst intensity has attracted much attention in these recent years, as it can guide the design of engineering in deep underground conditions and avoid injury to people. In this study, a new ensemble classifier combining a random forest classifier (RF) and beetle antennae search algorithm (BAS) has been designed and applied to improve the accuracy of rockburst classification. A large dataset was collected from across the world to achieve a comprehensive representation, in which five key influencing factors were selected as the input variables, and the rockburst intensity was selected as the output. The proposed model BAS-RF was then validated by the dataset. The results show that BAS could tune the hyperparameters of RF efficiently, and the optimum model exhibited a high performance on an independent test set of rockburst data and new engineering projects. According to the ensemble RF-BAS model, the feature importance was calculated. Furthermore, the accuracy of the proposed model on rockburst prediction was higher than the conventional machine learning models and empirical models, which means that the proposed model is efficient and accurate.
Parallel Algorithms for Solving Inverse Gravimetry Problems: Application for Earth’s Crust Density Models Creation
Authors: Martyshko Petr , Ladovskii Igor , Byzov Denis
Published: November 2021

The paper describes a method of gravity data inversion, which is based on parallel algorithms. The choice of the density model of the initial approximation and the set on which the solution is sought guarantees the stability of the algorithms. We offer a new upward and downward continuation algorithm for separating the effects of shallow and deep sources. Using separated field of layers, the density distribution is restored in a form of 3D grid. We use the iterative parallel algorithms for the downward continuation and restoration of the density values (by solving the inverse linear gravity problem). The algorithms are based on the ideas of local minimization; they do not require a nonlinear minimization; they are easier to implement and have better stability. We also suggest an optimization of the gravity field calculation, which speeds up the inversion. A practical example of interpretation is presented for the gravity data of the Urals region, Russia.
Observer-Based Control for Nonlinear Time-Delayed Asynchronously Switching Systems: A New LMI Approach
Authors: Taghieh Amin , Mohammadzadeh Ardashir , Tavoosi Jafar , Mobayen Saleh , Rojsiraphisal Thaned , Asad Jihad H. , Zhilenkov Anton
Published: November 2021

This paper designs an observer-based controller for switched systems (SSs) with nonlinear dynamics, exogenous disturbances, parametric uncertainties, and time-delay. Based on the multiple Lyapunov–Krasovskii and average dwell time (DT) approaches, some conditions are presented to ensure the robustness and investigate the effect of time-delay, uncertainties, and lag issues between switching times. The control parameters are determined through solving the established linear matrix inequalities (LMIs) under asynchronous switching. A novel LMI-based conditions are suggested to guarantee the H∞ performance. Finally, the accuracy of the designed observer-based controller is examined by simulations on practical case-study plants.
Effect of Ferritic Morphology on Yield Strength of CGHAZ in a Low Carbon Mo-V-N-Ti-B Steel
Authors: Wang Leping , Fan Huibing , Shi Genhao , Wang Qiuming , Wang Qingfeng , Zhang Fucheng
Published: November 2021

For investigating the impact of ferritic morphology on yield strength (YS) of the high-heat-input welding induced coarse-grained heat-affected zone (CGHAZ) of a low carbon Mo-V-N-Ti-B steel, a group of particular welding heat inputs were designed to obtain different ferritic microstructures in CGHAZ. The tensile properties were estimated from typical samples with ferritic microstructures. The mixed microstructures dominated by the intragranular polygonal ferrite (IGPF), the intragranular acicular ferrite (IGAF), and the granular bainite (GB) were obtained at the heat inputs of 35, 65, 85 and 120 kJ/cm, respectively. When the main microstructure changed from IGPF to IGAF and GB, YS increased first and then decreased. The microstructure consisting mainly of IGAF possessed the maximum YS. As the main microstructure changed from IGPF to IGAF and GB, the contribution of grain refinement strengthening to YS was estimated to be elevated remarkably. This means the strength of CGHAZ in a low-carbon steel subjected to the high-heat-input welding could be enhanced by promoting the fine-grained AF and GB formation.
Error Uncertainty Analysis in Planar Closed-Loop Structure with Joint Clearances
Authors: Yu Yushu , Li Jinglin , Li Xin , Yang Yi
Published: November 2021

For planar closed-loop structures with clearances, the angular and positional error uncertainties are studied. By using the vector translation method and geometric method, the boundaries of the errors are analyzed. The joint clearance is considered as being distributed uniformly in a circle area. A virtual link projection method is proposed to deal with the clearance affected length error probability density function (PDF) for open-loop links. The error relationship between open loop and closed loop is established. The open-loop length PDF and the closed-loop angular error PDF both approach being Gaussian distribution if there are many clearances. The angular propagation error of multi-loop structures is also investigated by using convolution. The positional errors of single and multiple loops are both discussed as joint distribution functions. Monte Carlo simulations are conducted to verify the proposed methods.
Recent Advances and Challenges of Nanomaterials-Based Hydrogen Sensors
Authors: Wang Bei , Sun Ling , Schneider-Ramelow Martin , Lang Klaus-Dieter , Ngo Ha-Duong
Published: November 2021

Safety is a crucial issue in hydrogen energy applications due to the unique properties of hydrogen. Accordingly, a suitable hydrogen sensor for leakage detection must have at least high sensitivity and selectivity, rapid response/recovery, low power consumption and stable functionality, which requires further improvements on the available hydrogen sensors. In recent years, the mature development of nanomaterials engineering technologies, which facilitate the synthesis and modification of various materials, has opened up many possibilities for improving hydrogen sensing performance. Current research of hydrogen detection sensors based on both conservational and innovative materials are introduced in this review. This work mainly focuses on three material categories, i.e., transition metals, metal oxide semiconductors, and graphene and its derivatives. Different hydrogen sensing mechanisms, such as resistive, capacitive, optical and surface acoustic wave-based sensors, are also presented, and their sensing performances and influence based on different nanostructures and material combinations are compared and discussed, respectively. This review is concluded with a brief outlook and future development trends.
Edge Cooling of a Fuel Cell during Aerial Missions by Ambient Air
Authors: Zakhvatkin Lev , Schechter Alex , Buri Eilam , Avrahami Idit
Published: November 2021

During aerial missions of fuel-cell (FC) powered drones, the option of FC edge cooling may improve FC performance and durability. Here we describe an edge cooling approach for fixed-wing FC-powered drones by removing FC heat using the ambient air during flight. A set of experiments in a wind tunnel and numerical simulations were performed to examine the efficiency of FC edge cooling at various flight altitudes and cruise speeds. The experiments were used to validate the numerical model and prove the feasibility of the proposed method. The first simulation duplicated the geometry of the experimental setup and boundary conditions. The calculated temperatures of the stack were in good agreement with those of the experiments (within ±2 °C error). After validation, numerical models of a drone’s fuselage in ambient air with different radiator locations and at different flight speeds (10–30 m/s) and altitudes (up to 5 km) were examined. It was concluded that onboard FC edge cooling by ambient air may be applicable for velocities higher than 10 m/s. Despite the low pressure, density, and Cp of air at high altitudes, heat removal is significantly increased with altitude at all power and velocity conditions due to lower air temperature.
Silicon Nitride Interface Engineering for Fermi Level Depinning and Realization of Dopant-Free MOSFETs
Authors: Richstein Benjamin , Hellmich Lena , Knoch Joachim
Published: November 2021

Problems with doping in nanoscale devices or low temperature applications are widely known. Our approach to replace the degenerate doping in source/drain (S/D)-contacts is silicon nitride interface engineering. We measured Schottky diodes and MOSFETs with very thin silicon nitride layers in between silicon and metal. Al/SiN/p-Si diodes show Fermi level depinning with increasing SiN thickness. The diode fabricated with rapid thermal nitridation at 900 ∘C reaches the theoretical value of the Schottky barrier to the conduction band ΦSB,n=0.2 eV. As a result, the contact resistivity decreases and the ambipolar behavior can be suppressed. Schottky barrier MOSFETs with depinned S/D-contacts consisting of a thin silicon nitride layer and contact metals with different work functions are fabricated to demonstrate unipolar behavior. We presented n-type behavior with Al and p-type behavior with Co on samples which only distinguish by the contact metal. Thus, the thermally grown SiN layers are a useful method suppress Fermi level pinning and enable reconfigurable contacts by choosing an appropriate metal.