bluuebunny/crossref_metadata_2025 huggingface dataset:
A Method to Construct Depth Datum Geodesic Height Model for GNSS Bathymetric Survey
Authors: Tian Chenyang , Guan Minglei , Cheng Yaxin , Zhang Wei , Zhang Dejin , Yang Jinfeng
Published: December 2022

Water depth measurement requires the establishment of one or more tidal stations in the survey area for synchronous water level observation, and finally the water depth is estimated to the depth datum. The non-tidal observation measuring has high efficiency and avoids the water level correction error caused by tidal observation in traditional sounding. Therefore, non-tidal observation measuring has become an effective water depth measurement method in offshore and inland water. However, datum conversion in non-tide operation is mostly based on the polynomial fitting method. The accuracy of this method is influenced by the distribution of datum control points, topographic relief and operation ranges. In this paper, we present a method to construct a depth datum geodesic height model, which can directly obtain a bathymetric database of depth data in a GNSS bathymetric survey. The model incorporates the continuous depth datum and the mean sea level of geodetic height in the same area. Through the numerical simulation of tidal wave motion in regional water, the tidal model is obtained. Based on the grid model, the tidal level is extracted from the tidal model for harmonic analysis, and a continuous depth datum model is established. Mean sea level geodetic height is from the CNES-CLS2015 Average Sea Surface Model. In this paper, the model is confirmed in the South Yellow Sea area. The results show that the accuracy of the depth datum model, and the depth datum geodetic height model meets the accuracy requirements of the datum.
An Introduction to the Application of Marine Controlled-Source Electromagnetic Methods for Natural Gas Hydrate Exploration
Authors: Li Yuan , Slob Evert , Werthmüller Dieter , Wang Lipeng , Lu Hailong
Published: December 2022

Natural gas hydrates have been an unconventional source of energy since the beginning of this century. Gas-hydrate-filled reservoirs show higher resistivity values compared with water-filled sediments. Their presence can be detected using marine controlled-source electromagnetic methods. We classify acquisition configurations into stationary and moving receiver configurations, which are described in terms of the design group, the operational details, and where they have been used successfully in the field for natural gas hydrate exploration. All configurations showed good numerical results for the detection of a 700 m long gas hydrate reservoir buried 200 m below the seafloor, but only the stationary configurations provided data that can be used to estimate the horizontal boundaries of the resistive part of the reservoir when the burial depth is known from seismic data. We discuss the operational steps of the configurations and provide the steps on how to choose a suitable configuration. Different CSEM configurations were used together with seismic data to estimate the edge of the gas hydrate reservoir and the total volume of the gas hydrates, to optimize the drilling location, to increase production safety, and to improve geological interpretations. It seems that CSEM has become a reliable method to aid in the decision-making process for gas hydrate reservoir appraisal and development.
Impact of Hyperglycemia and Diabetes Mellitus on Breakthrough Mucormycosis Outcomes in Patients with Hematologic Malignancies—Complex and Intriguing Associations
Authors: Franklin Alexander , Wurster Sebastian , Axell-House Dierdre B. , Jiang Ying , Kontoyiannis Dimitrios P.
Published: December 2022

Mucormycosis (MCR) is frequently associated with diabetic ketoacidosis and hyperglycemia, as well as hematologic malignancies (HMs) and hematopoietic stem cell transplantation (HSCT). However, little is known about the effect of hyperglycemia on MCR outcomes in patients with HMs. We therefore conducted a retrospective cohort study of adult patients hospitalized with MCR and HM or HSCT (n = 103) at MD Anderson Cancer Center from April 2000 through to April 2020. Twenty-three patients (22%) had documented episodes of severe hyperglycemia. Sixty patients had >5 serum glucose measurements within 28 days prior to MCR symptom onset; of those, 14 (23%) met the criteria for persistent hyperglycemia. Sixteen patients (16%) received insulin prior to admission. The crude mortality 42 days from the onset of MCR symptoms in our cohort was 31%. Neither severe nor persistent hyperglycemia were associated with excess mortality. Insulin use prior to index admission was associated with decreased 42-day mortality on univariate analysis (p = 0.031). In conclusion, in a setting of high crude mortality, severe and/or persistent hyperglycemia do not appear to be associated with excess mortality in patients with HM or HSCT developing MCR. Insulin use prior to MCR diagnosis may be associated with decreased mortality, although further research is needed to validate this effect and to study its mechanistic underpinnings.
Predictors of Self-Assessed and Actual Knowledge about Diabetes among Nursing Students in Saudi Arabia
Authors: Alsolais Abdulellah M. , Bajet Junel Bryan , Alquwez Nahed , Alotaibi Khalaf Aied , Almansour Ahmed Mansour , Alshammari Farhan , Cruz Jonas Preposi , Alotaibi Jazi Shaydied
Published: December 2022

The aim of this study was to investigate the predictors of self-assessed and actual knowledge of diabetes among undergraduate nursing students. Nursing education plays an important role in preparing future nurses and ensuring that they are knowledgeable and competent in diabetes care. A descriptive, cross-sectional study was conducted with a convenience sample of 330 undergraduate Saudi student nurses. We collected data from October to December 2019 using the Diabetes Self-report Tool (DSRT) and Diabetes Basic Knowledge Tool (DBKT). We performed a multiple regression analysis to identify the predictors of self-reported and actual knowledge of diabetes. The students’ overall mean (SD) scores in the DSRT and DBKT were 48.31 (5.71), which is equivalent to 80.52% of the total score and 22.54 (8.57), respectively. The students’ university, gender, year level and experience in providing direct care to diabetic patients were the significant predictors of self-reported knowledge, whereas their university, age and perceived diabetes knowledge were the significant predictors of actual diabetes knowledge. The findings underscore the necessity to improve student nurses’ actual knowledge of diabetes and its management. Our findings provide a solid basis for planning and implementing educational interventions with diabetes-related information to ensure adequate diabetes knowledge among nursing students.
Clinical Value of IL6R Gene Variants as Predictive Biomarkers for Toxicity to Tocilizumab in Patients with Rheumatoid Arthritis
Authors: Sainz Luis , Riera Pau , Moya Patricia , Bernal Sara , Casademont Jordi , Díaz-Torné Cesar , Millán Ana Milena , Park Hye Sang , Lasa Adriana , Corominas Héctor
Published: December 2022

Tocilizumab is a first-line biologic disease-modifying anti-rheumatic drug (bDMARD) that inhibits the interleukin-6 (IL-6) pathway by antagonizing the IL-6 receptor (IL-6R). Tocilizumab is widely used to treat rheumatoid arthritis (RA), a prevalent autoimmune disease that can cause irreversible joint damage and disability. Although many bDMARDs have been developed for RA, there is a lack of validated biomarkers which could guide personalized medicine strategies. To evaluate whether single-nucleotide polymorphisms (SNPs) in the IL6R gene could predict tocilizumab toxicity in patients with RA, we conducted a retrospective cohort study of 88 patients treated with tocilizumab. Six SNPs previously described in the IL6R gene were genotyped (rs12083537, rs11265618, rs4329505, rs2228145, rs4537545, and rs4845625). Using parametric tests, we studied the association between the SNPs and hepatotoxicity, infection, hypersensitivity, gastrointestinal, hematological, and dyslipidemia adverse events (AEs). We found associations between dyslipidemia and rs4845625 and between hematological AEs and rs11265618 and rs4329505. No further associations were found for the remaining SNPs and other AEs. Our findings support the potential clinical value of SNPs in the IL6R gene as predictive biomarkers for toxicity to tocilizumab in patients with RA.
Early Hypocalcemia in Severe Trauma: An Independent Risk Factor for Coagulopathy and Massive Transfusion
Authors: Vettorello Marco , Altomare Michele , Spota Andrea , Cioffi Stefano Piero Bernardo , Rossmann Marta , Mingoli Andrea , Chiara Osvaldo , Cimbanassi Stefania
Published: December 2022

The rapid identification of patients at risk for massive blood transfusion is of paramount importance as uncontrolled exsanguination may lead to death within 2 to 6 h. The aim of this study was to analyze a cohort of severe trauma patients to identify risk factors associated with massive transfusion requirements and hypocalcemia. All major trauma (ISS > 16) presented directly from the scene to the Niguarda hospital between 1 January 2015 and 31 December 2021 were analyzed. A total of 798 patients were eligible out of 1586 screened. Demographic data showed no significant difference between hypocalcemic (HC) and normocalcemic (NC) patients except for the presence of crush trauma, alcohol intake (27% vs. 15%, p < 0.01), and injury severity score (odds ratio 1.03, p = 0.03). ISS was higher in the HC group and was an independent, even if weak, predictor of hypocalcemia (odds ratio 1.03, p = 0.03). Prehospital data showed a lower mean systolic arterial pressure (SAP) and a higher heart rate (HR) in the HC group (105 vs. 127, p < 0.01; 100 vs. 92, p < 0.001, respectively), resulting in a higher shock index (SI) (1.1 vs. 0.8, p < 0.001). Only retrospective studies such as ours are available, and while hypocalcemia seems to be an independent predictor of mortality and massive transfusion, there is not enough evidence to support causation. Therefore, randomized prospective studies are suggested.
Evaluation of a Novel Technique for Closure of Small Palatal Fistula
Authors: Brauner Edoardo , Piccoli Luca , Sallemi Karim , Romeo Umberto , Laudoni Federico , Cantore Marco , Tenore Gianluca , Pranno Nicola , De Angelis Francesca , Di Cosola Michele , Valentini Valentino , Di Carlo Stefano
Published: December 2022

A palatal fistula is a pathological condition that connects the nasal cavities with the oral cavity. An oral–nasal fistula is reported as a possible post-surgical complication after the removal of oral carcinomas. The presence of a palatal fistula affects the patient’s quality of life, making it necessary to apply a prosthetic device, such as a palatal plate, to keep the nasal cavities separated from the oral one. There are several surgical techniques to close a palatal fistula, but it is not possible to define the optimal technique as the approach is extremely dependent on the characteristics of the fistula. The aim of this article is to propose a minimally invasive technique to reduce the size of palatal fistulae and to reduce the surgical difficulty (NSPF). A total of 20 patients fulfilled the inclusion criteria and were checked every two weeks. The fistula was injured with a needle every 2 weeks. Fifteen patients who healed with complete closure of the fistula reported no need for a palatal protection plate to eat, drink and speak normally. It is possible to conclude that the NSPF protocol is a valid approach for the non-surgical reduction of palatal fistulae, and it is possible, when the appropriate conditions are present, to achieve complete closure.
Hydrogen Gas Treatment Improves Postoperative Delirium and Cognitive Dysfunction in Elderly Noncardiac Patients
Authors: Lin Hua , Du Jian , Tian Zhigang , Yu Yonghao , Cui Yan , Xie Keliang
Published: December 2022

Purpose: Postoperative delirium is a state of acute brain dysfunction characterized by fluctuating mental status that affects millions of patients each year. We used prophylactic inhalation of hydrogen gas in elderly patients undergoing elective surgery to compare their occurrence of postoperative delirium with that of controls. Methods: A total of 184 patients aged ≥ 65 years were enrolled and randomized into either a control group or a hydrogen inhalation group. The quality of sleep was assessed 1 day before and 1, 3, and 7 days after surgery at 8 A.M. The Confusion Assessment Method (CAM) was used as a screening tool for delirium and assessed the patients’ state of consciousness 1–7 days after surgery. Results: Postoperative delirium occurred in 17 (24%) of 70 patients without hydrogen inhalation and in 10 (12%) of 83 patients after hydrogen inhalation. The incidence of delirium was decreased in the hydrogen group. No significant differences were found between length of stay in hospital after surgery and sleep quality at 1, 3, and 7 days postoperatively between the two groups. The numerical rating scale (NRS) pain scores were higher in the hydrogen group (4.08 ± 1.77) than the control group (3.54 ± 1.77) on day 1 (p < 0.05); however, the mean difference between the two groups was small (1 to 1.6). There were no significant differences on day 3 and 7. The postoperative C-reactive protein level was significantly lower in the hydrogen group than the control group. Conclusions: This study suggests that hydrogen inhalation can prevent postoperative delirium in elderly noncardiac patients by reducing the inflammatory response.
International Trade in the Post-Soviet Space: Trends, Threats, and Prospects for the Internal Trade within the Eurasian Economic Union
Authors: Kot Vera , Barsukova Arina , Strielkowski Wadim , Krivko Mikhail , Smutka Luboš
Published: December 2022

This paper discusses the dynamics of foreign trade in the post-Soviet space within the Eurasian Economic Union (EAEU) during the period from 2015 to 2021. Additionally, the paper analyzes export indicators in foreign and mutual trade of the EAEU member countries and diversification of the commodity structure as well as its dynamics based on the commodity concentration index for each member country. Our paper identifies the strengths and weaknesses of the EAEU, analyzes the opportunities and threats of development, and focuses on the trends and prospects. The main strengths include the institutional and legal structure of the EAEU single market, the historical, cultural, and economic proximity of the EAEU member countries, the transit potential of the territory, the high level of domestic trade, and the increasing share of ruble transactions in the trade turnover. The most significant weaknesses are the low efficiency of the institutional structure, the gap in the socio-economic level of development of the participating countries, unstable geopolitical situations in some member countries, the low level of recognition of the EAEU in the world market, economic and political conflicts of interests of the member countries, and the dependence on Western technologies in some key industries. Strategically important opportunities can be found in the creation and implementation of a long-term development strategy, diversification of trade with the Middle East and Asian countries, expansion in terms of the territorial composition, development of the institutional and legal structure as well as cooperation ties, as well as the cooperation in the field of technological innovation and financial security. Among the most significant threats were identified the outpacing growth in the share of EAEU members’ trade with China, the expansion of economic and political contradictions between the EAEU member countries, and the strengthening of the positions of alternative currencies in foreign trade.
How Does Poverty Alleviation Relocation Affect the Non-Agricultural Employment of Women’s Labor Forces? Evidence from Southern Shaanxi Province
Authors: Zhu Yongtian , Guan Rui , Yu Jin
Published: December 2022

With the completion of the relocation task, fully promoting the non-agricultural employment of relocated women is of great significance for improving the livelihood sustainability of relocated peasant households’ and consolidating the results of poverty alleviation. Based on the sample data of 1616 rural households in southern Shaanxi Province, China, using the IV-Probit model, IV-Tobit model, and mediation effect model, this study empirically analyzes the impact and mechanism of participation in relocation on women’s non-agricultural employment. The results show that by introducing an instrumental variable to solve endogeneity, participation in relocation has a significant positive impact on the behavior and intensity of women’s non-agricultural employment. A mechanism analysis shows that training, public services, and land abandonment play a mediation role in the relationship between participation in relocation and women’s non-agricultural employment. In terms of women’s non-agricultural employment behavior, the mediation effects are 56.9%, 15.0%, and 11.0%, respectively. In terms of women’s non-agricultural employment intensity, the mediation effects are 58.5%, 15.7%, and 11.6%, respectively. Based on the above findings, this study puts forward policy implications for follow-up relocation support, to further release the surplus women’s labor forces and promote women’s non-agricultural employment.
Hydrolipidic Characteristics and Clinical Efficacy of a Dermocosmetic Formulation for the Improvement of Homeostasis on Oily Mature Skin
Authors: Kakuda Letícia , Melo Maísa Oliveira de , Campos Patrícia Maria Berardo Gonçalves Maia
Published: December 2022

Background: Although the scientific literature associates mature skin with dry skin and the secretion of sebum on the face decreases over the years, in tropical countries, such as Brazil, mature skin can still present oily characteristics. Thus, the knowledge of the hydrophilic characteristics of mature skin is fundamental to help the development of more effective treatments for this skin type. In this context, the study aimed to evaluate the hydrophilic characteristics and the clinical efficacy of a cosmetic formulation for mature skin added with alfalfa and lentil extracts by using biophysical and skin imaging techniques. Methods: Twenty-eight healthy females aged between 45 and 59 years were enrolled. Measurements of the stratum corneum water content, sebum content, transepidermal water loss, skin microrelief, and pores count were performed before and after the 28-day formulation application. Results: The mature skin presented as oily with wrinkles and pores. The proposed formulation significantly reduced the sebum content and the number of fine and large pores and improved skin microrelief and hydration after a 28-day period of the application when compared to the vehicle. Conclusions: The proposed formulation was effective in oily mature skin treatment, improving its general skin aging and oiliness conditions, and reducing pores count in just 28 days.
DsDBF1, a Type A-5 DREB Gene, Identified and Characterized in the Moss Dicranum scoparium
Authors: Onele Alfred O. , Mazina Anastasia B. , Leksin Ilya Y. , Minibayeva Farida V.
Published: December 2022

Plant dehydration-responsive element binding (DREB) transcription factors (TFs) play important roles during stress tolerance by regulating the expression of numerous genes involved in stresses. DREB TFs have been extensively studied in a variety of angiosperms and bryophytes. To date, no information on the identification and characterization of DREB TFs in Dicranum scoparium has been reported. In this study, a new DBF1 gene from D. scoparium was identified by cloning and sequencing. Analysis of the conserved domain and physicochemical properties revealed that DsDBF1 protein has a classic AP2 domain encoding a 238 amino acid polypeptide with a molecular mass of 26 kDa and a pI of 5.98. Subcellular prediction suggested that DsDBF1 is a nuclear and cytoplasmic protein. Phylogenetic analysis showed that DsDBF1 belongs to group A-5 DREBs. Expression analysis by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) revealed that DsDBF1 was significantly upregulated in response to abiotic stresses such as desiccation/rehydration, exposure to paraquat, CdCl2, high and freezing temperatures. Taken together, our data suggest that DsDBF1 could be a promising gene candidate to improve stress tolerance in crop plants, and the characterization of TFs of a stress tolerant moss such as D. scoparium provides a better understanding of plant adaptation mechanisms.
1-(4-{[3,5-bis({[3,5-Dimethyl-4-(4-methyl-3,5-dioxo-1,2,4-triazolidin-1-yl)-phenoxy]methyl})phenyl]methoxy}-2,6-dimethyl-phenyl)-4-methyl-1,2,4-triazolidine-3,5-dione
Authors: Breton Gary W. , Bowron James Alexander
Published: December 2022

Appropriately substituted N-centered urazolyl radicals are capable of generating interesting cage-like structures upon forming N-N bonds. The radicals are generated by the oxidation of the corresponding NH urazole precursors. We synthesized a triurazole precursor that we hoped would dimerize through the formation of three N-N bonds to afford a large molecular cage. Unfortunately, the attempts at the oxidation of the urazoles to form urazolyl radicals instead only lead to random oligomerization, forming plastic-like materials rather than the desired cages.
Material Removal Capability and Profile Quality Assessment on Silicon Carbide Micropillar Fabrication with a Femtosecond Laser
Authors: Zhang Xifang , Hou Zhibao , Song Jiacheng , Jin Zhiyi , Yao Zhenqiang
Published: December 2022

Silicon carbide (SiC) has a variety of applications because of its favorable chemical stability and outstanding physical characteristics, such as high hardness and high rigidity. In this study, a femtosecond laser with a spiral scanning radial offset of 5 μm and a spot radius of 6 μm is utilized to process micropillars on a SiC plate. The influence of pulsed laser beam energies and laser translation velocities on the micropillar profiles, dimensions, surface roughness Ra, and material removal capability (MRC) of micropillars was investigated. The processing results indicate that the micropillar has the best perpendicularity, with a micropillar bottom angle of 75.59° under a pulsed beam energy of 50 μJ in the range of 10–70 μJ, with a pulsed repetition rate of 600 kHz and a translation velocity of 0.1 m/s. As the laser translation velocity increases between 0.2 m/s and 1.0 m/s under a fixed pulsed beam energy of 50 μJ and a constant pulsed repetition rate of 600 kHz, the micropillar height decreases from 119.88 μm to 81.79 μm, with the MRC value increasing from 1.998 μm3/μJ to 6.816 μm3/μJ, while the micropillar bottom angle increases from 68.87° to 75.59°, and the Ra value diminishes from 0.836 μm to 0.341 μm. It is suggested that a combination of a higher pulsed laser beam energy with a faster laser translation speed is recommended to achieve micropillars with the same height, as well as an improved processing efficiency and surface finish.
Can Abutment with Novel Superlattice CrN/NbN Coatings Influence Peri-Implant Tissue Health and Implant Survival Rate Compared to Machined Abutment? 6-Month Results from a Multi-Center Split-Mouth Randomized Control Trial
Authors: Pera Francesco , Menini Maria , Alovisi Mario , Crupi Armando , Ambrogio Giulia , Asero Sofia , Marchetti Carlotta , Canepa Camilla , Merlini Laura , Pesce Paolo , Carossa Massimo
Published: December 2022

Background: The aim of the present multi-center split-mouth randomized control trial was to investigate the effect on peri-implant tissue of abutment with chromium nitride/ niobium nitride (CrN/NbN) coatings (superlattice) compared to traditional machined surface. Methods: Two adjacent posterior implants were inserted in 20 patients. A machined abutment was randomly screwed on either the mesial or distal implant, while a superlattice abutment was screwed on the other one. Implant survival rate, peri-implant probing depth (PPD), plaque index (PI), and bleeding index (BI) were collected 6 months after surgery, while marginal bone loss (MBL) was evaluated at T0 and T6.; Results: Implant survival rate was 97.7%. A total MBL of 0.77 ± 0.50 mm was recorded for superlattice abutments, while a mean MBL of 0.79 ± 0.40 mm was recorded for the abutment with machined surface. A mean PPD of 1.3 ± 0.23 mm was recorded for the superlattice Group, and a mean PPD of 1.31 ± 0.3 was recorded for the machined surface Group. PI was of 0.55 ± 0.51 for superlattice Group and 0.57 ± 0.50 for machined Group, while BI was of 0.47 ± 0.49 for superlattice Group and of 0.46 ± 0.40 for the machined one. No statistically significant difference was highlighted between the two Groups (p > 0.05). Conclusions: After a 6-month observational period, no statistically significant differences were highlighted between superlattice abutment and traditional machined abutment. Further in vitro studies as well as clinical research with longer follow-ups are required to better investigate the surface properties of the novel abutments’ superlattice coating and its effect on the oral tissues.
Features of the Defect Structure and Luminescence of Nominally Pure Lithium Niobate Crystals Produced Using Different Technologies
Authors: Smirnov Maxim , Manukovskaya Diana , Sidorov Nikolay , Palatnikov Mikhail
Published: December 2022

We have established that luminescence in lithium niobate crystals both congruent and near-stoichiometric (R ≈ 1) is due to point defects in the cationic sublattice and intraconfigurational transitions in the oxygen-octahedral NbO6 clusters. We have also determined that the main contribution to the luminescence in the visible and near IR regions is made by luminescence centers with the participation of NbLi defects: the NbLi-NbNb bipolaron pair and the NbLi-O defect in a congruent crystal. The minimum intensity of bipolaron luminescence has been observed in stoichiometric crystals obtained using different technologies. Weak luminescence of the NbLi-NbNb bipolaron pair indicates a small number of NbLi defects in the crystal structure. The number of NbLi defects in the crystal structure indicates a deviation of the crystal composition from stoichiometry.
RE3+-Doped Ca3(Nb,Ga)5O12 and Ca3(Li,Nb,Ga)5O12 Crystals (RE = Sm, Dy, and Pr): A Review of Current Achievements
Authors: Gheorghe Cristina , Hau Stefania , Gheorghe Lucian , Voicu Flavius , Greculeasa Madalin , Broasca Alin , Stanciu George
Published: December 2022

Spectroscopic characteristics of RE3+ ions (RE = Sm, Dy, and Pr) doped in partially disordered Ca3Nb1.6875Ga3.1875O12-CNGG and Ca3Li0.275Nb1.775Ga2.95O12-CLNGG crystals are reviewed in detail to assess their prospects as laser crystals with emission in the visible spectral domain. All investigated crystals were grown using the Czochralski crystal growth technique. High-resolution absorption and emission measurements at different temperatures, as well as emission dynamics measurements, were performed on the grown crystals. The spectroscopic and laser emission characteristics of the obtained crystals were determined based on the Judd-Ofelt parameters. The obtained results indicate that CNGG:RE3+ and CLNGG:RE3+ (RE = Sm, Dy, and Pr) crystals can be promising materials for lasers in the visible range.
Effect of Laser Micro-Texturing on Laser Joining of Carbon Fiber Reinforced Thermosetting Composites to TC4 Alloy
Authors: Jiao Junke , Xu Jihao , Jing Chenghu , Cheng Xiangyu , Wu Di , Ru Haolei , Zeng Kun , Sheng Liyuan
Published: December 2022

Carbon fiber reinforced thermosetting composites (CFRTS) and TC4 alloy are important structural materials for lightweight manufacturing. The hybrid structure of these two materials has been widely used in the aerospace field. However, the CFRTS-TC4 alloy joint formed by the traditional connection method has many challenges, such as poor environmental adaptability and stress concentration. Laser micro-texturing of metal surface-assisted laser connection of CFRTS and TC4 alloy has great potential in improving joint strength. In order to study the effect of laser micro-texturing on the laser bonding of CFRTS and TC4 alloy, the simulation and experimental research of laser welding of TC4 alloy and CFRTS based on laser micro-textures with different scanning spacings were carried out, and the interface hybrid pretreatment method of laser cleaning and laser plastic-covered treatment was introduced to assist the high-quality laser bonding of heterogeneous joints. The results showed that the established finite element model of CFRTS-TC4 alloy laser welding can predict the temperature field distribution of the joint during the welding process and reflect the forming mechanism of the joint. The laser micro-textures with different scanning spacings will lead to a difference in the temperature field distribution on the polyamide (PA6) interface, which leads to a change in heat input on the CFRTS surface. When the laser scanning spacing is 0.3 mm, the joint strength can reach 14.3 MPa. The failure mechanism of the joint mainly includes the cohesive failure of the internal tear of the carbon fiber and the interfacial failure of the interface between the PA6 resin and the TC4 alloy.
Mechanical Properties of New Generations of Monolithic, Multi-Layered Zirconia
Authors: Bruhnke Maria , Awwad Yasmin , Müller Wolf-Dieter , Beuer Florian , Schmidt Franziska
Published: December 2022

New monolithic multi-layered zirconia restorations are gaining popularity due to their excellent aesthetic properties. However, current knowledge of these newest multi-layer ceramics in terms of mechanical properties is scarce. Three monolithic, multi-layered zirconia materials (Katana, Kuraray Noritake, Japan) were selected for comparison: High Translucent Multi-layered zirconia (HTML), Super Translucent Multi-layered zirconia (STML) and Ultra Translucent Multi-layered zirconia (UTML). Fifteen specimens per group were cut from pre-sintered blocs in each of the four layers (L1, L2, L3, L4) and in different thicknesses (0.4 mm, 0.8 mm and 1.2 mm). Critical fracture load (Fcf) was recorded in 3-point-bending. Flexural strength (σ) in MPa, Vickers hardness (HV) in N/mm2, fracture toughness (KIc) in MPa*m1/2, Weibull Modulus (m) and characteristic Weibull strength (σw) in MPa were assessed. Statistical analysis was performed using ANOVA analysis. FS and KIc were significantly higher (p < 0.05) for Katana™ HTML (652.85 ± 143.76–887.64 ± 118.95/4.25 ± 0.43–5.01 ± 0.81) in comparison to Katana™ STML (280.17 ± 83.41–435.95 ± 73.58/3.06 ± 0.27–3.84 ± 0.47) and UTML (258.25 ± 109.98–331.26 ± 56.86/2.35 ± 0.31–2.94 ± 0.33), with no significant differences between layers and layer thicknesses. The range of indications should be carefully considered when selecting the type of monolithic zirconia for fabrication of dental restorations, as materials widely differ in mechanical properties.
Multifunctional Polyurethane Composites with Coffee Grounds and Wood Sawdust
Authors: Bartczak Przemysław , Stachowiak Julia , Szmitko Marta , Grząbka-Zasadzińska Aleksandra , Borysiak Sławomir
Published: December 2022

Currently, the fundamental activity that will allow for the development of an economy with closed circulation is the management of food waste and production waste for the preparation of biocomposites. The use of waste materials of natural origin allows for the creation of innovative composites with improved physicochemical and functional properties. The present investigation concerns the use of coffee grounds (2.5–20 wt.%) and oak sawdust (2.5–20 wt.%) as effective fillers of rigid polyurethane foam. Innovative composite materials, previously indebted in the literature, were subjected to the necessary analyses to determine the application abilities: processing times, free density, water absorption, dimensional stability, mechanical properties (compressive strength), thermal conductivity, morphology, and flame resistance. The results with respect to the mechanical tests turned out to be the key. Increasing the number of coffee additives has a positive effect on the compressive strength. The addition of this filler in the range of 5–15 wt.% increased the compressive strength of the composites, 136–139 kPa, compared to the reference sample, 127 kPa. The key parameter analysed was thermal conductivity. The results obtained were in range of the requirements, that is, 0.022–0.024 W/m·K for all used amounts of fillers 2.5–20 wt.%. This is extremely important since these materials are used for insulation purposes. The results of the burning-behaviour test have confirmed that the addition of renewable materials does not negatively affect the fire resistance of the received foams; the results were obtained analogously to those obtained from the reference sample without the addition of fillers. The height of the flame did not exceed 17 cm, while the flame decay time was 17 s for the reference sample and the composite with coffee grounds and 18 s for the composite with oak sawdust. In this work, the practical application of bioorganic waste as an innovative filler for the insulation of flooded polyurethane foam is described for the first time. The introduction of fillers of natural origin into the polymer matrix is a promising method to improve the physicochemical and functional properties of rigid polyurethane foams. Composites modified with coffee grounds and sawdust are interesting from a technological, ecological, and economic point of view, significantly increasing the range of use of foam in various industries.
The Comparation of Arrhenius-Type and Modified Johnson–Cook Constitutive Models at Elevated Temperature for Annealed TA31 Titanium Alloy
Authors: Yang Shengli , Liang Pei , Gao Fuyang , Song Dejun , Jiang Peng , Zhao Min , Kong Ning
Published: December 2022

Constitutive models play a significant role in understanding the deformation behavior of materials and in optimizing the manufacturing process. In order to improve the reliability of calculation results, the high temperature flow behavior of TA31 titanium alloy obtained from an annealed hot-rolled plate has been investigated by a Gleeble-3500 thermo-mechanical simulator. The isothermal hot compression tests are conducted in the temperature range of 850 to 1050 °C and the strain rate range from 0.001 to 10 s−1 with a height reduction of 60%. The annealed TA31 shows a dynamic recovery characteristic during thermo-mechanical processing. The experimental data have been used to develop an Arrhenius-type constitutive model and a modified Johnson–Cook model under the consideration of coupling effect on strain, temperature, and strain rate, as well as the strain-softening phenomenon. The material parameters are determined by a global optimization method based on the initial values by means of a regression method. A comparation of the predicted results has been performed based on the modified Johnson–Cook model and those acquired from the Arrhenius-type model. The correlation coefficient and average absolute relative error of the modified Johnson–Cook model are 4.57% and 0.9945, respectively. However, when the optimization method has been applied, they are 15.77% and 0.9620 for the Arrhenius-type model, respectively. These results indicate that the modified Johnson–Cook model is more accurate and efficient in predicting the flow stress of annealed TA31 titanium alloy under a set of model material parameters. Furthermore, the simple mathematical expression of this model is helpful to incorporate it into the finite element software to obtain detailed and valuable information during the thermo-mechanical processing simulation for TA31 in further work.
Microstructure and Wear Resistance of Laser-Clad Ni–Cu–Mo–W–Si Coatings on a Cu–Cr–Zr Alloy
Authors: Zhao Xiaojun , Zhong Qi , Zhai Pengyuan , Fan Pengyu , Wu Ruiling , Fang Jianxiao , Xiao Yuxiang , Jiang Yuxiang , Liu Sainan , Li Wei
Published: December 2022

To improve the wear resistance of high-strength and high-conductivity Cu–Cr–Zr alloys in high-speed and heavy load friction environments, coatings including Ni–Cu, Ni–Cu-10(W,Si), Ni–Cu–10(Mo,W,Si), and Ni–Cu–15(Mo,W,Si) (with an atomic ratio of Mo,W to Si of 1:2) were prepared using coaxial powder-feeding laser cladding technology. The microstructure and wear performance of coatings were chiefly investigated. The results revealed that (Mo,W)Si2 and MoNiSi phases are found in the Ni–Cu–10(Mo,W,Si) and Ni–Cu–15(Mo,W,Si) coating. WSi2 phases are found in the Ni–Cu–10(W,Si) coating. The degree of grain refinement in Ni–Cu–10(Mo,W,Si) was greater than that of the Ni–Cu–10(W,Si) coating after the effect of Mo. The excellent wear resistance and micro-hardness of the Ni–Cu–15(Mo,W,Si) coating were attributed to the increase in its dispersion phase, which were approximately 34.72 mg/km and 428 HV, 27.1% and 590% higher than the Cu–Cr–Zr substrate, respectively. The existence of silicide plays an important role in grain refinement due to the promotion of nucleation and the inhibition of grain growth. In addition, the wear mechanism transformed from adhesive wear in the Ni–Cu coating with no silicides to abrasive wear in the Ni–Cu–15(Mo,W,Si) coating with high levels of silicides.
Online Cartesian Compliance Shaping of Redundant Robots in Assembly Tasks
Authors: Lukić Branko , Jovanović Kosta , Žlajpah Leon , Petrič Tadej
Published: December 2022

This paper presents a universal approach to shaping the mechanical properties of the interaction between a collaborative robot and its environment through an end-effector Cartesian compliance shaping. More specifically, the focus is on the class of kinematically redundant robots, for which a novel redundancy reconfiguration scheme for online optimization of the Cartesian compliance of the end-effector is presented. The null-space reconfiguration aims to enable the more efficient and versatile use of collaborative robots, including robots with passive compliant joints. The proposed approach is model-based and gradient-based to enable real-time computation and reconfiguration of the robot for Cartesian compliance while ensuring accurate position tracking. The optimization algorithm combines two coordinate frames: the global (world) coordinate frame commonly used for end-effector trajectory tracking; and the coordinate frame fixed to the end-effector in which optimization is computed. Another attractive feature of the approach is the bound on the magnitude of the interaction force in contact tasks. The results are validated on a torque-controlled 7-DOF KUKA LWR robot emulating joint compliance in a quasi-static experiment (the robot exerts a force on an external object) and a peg-in-hole experiment emulating an assembly task.
Influence of the Preparation Technique on the Magnetic Characteristics of ε-Fe2O3-Based Composites
Authors: Testov Dmitriy O. , Gareev Kamil G. , Khmelnitskiy Ivan K. , Kosterov Andrei , Surovitskii Leonid , Luchinin Victor V.
Published: December 2022

ε-Fe2O3 is an iron(III) oxide polymorph attracting an increasing interest due to its unique magnetic properties combining extremely high coercivity and relatively large saturation magnetization. We review existing methods for the ε-Fe2O3 synthesis focusing on synthesis speed, repeatability, manufacturability and purity of the final product. Samples of ε-Fe2O3 have been synthesized using the two methods that appear the most promising: silica gel impregnation and microemulsion. In both cases, ε-Fe2O3 and α-Fe2O3 are present in the final product as attested by X-ray diffraction patterns and magnetic properties (maximum coercive force at 300 K~1 Tesla). Two different precursors, iron(III) nitrate and iron(II) sulfate, have been used in the silica gel impregnation method. Somewhat surprisingly, iron sulfate proved superior yielding ε-Fe2O3 content of 69% in the total iron oxide product, compared to 25% for iron nitrate under the same synthesis conditions. These results pave the way for modifying the existing ε-Fe2O3 synthesis methods aiming to increase the content of the epsilon phase in the final product and, consequently, improve its physicochemical properties.
Scalar Field Cosmology from a Modified Poisson Algebra
Authors: Leon Genly , Millano Alfredo , Paliathanasis Andronikos
Published: December 2022

We investigate the phase space of a scalar field theory obtained by minisuperspace deformation. We consider quintessence or phantom scalar fields in the action that arises from minisuperspace deformation on the Einstein–Hilbert action. We use a modified Poisson algebra where Poisson brackets are the α-deformed ones and are related to the Moyal–Weyl star product. We discuss early- and late-time attractors and reconstruct the cosmological evolution. We show that the model can have the ΛCDM model as a future attractor if we initially consider a massless scalar field without a cosmological constant term.
Supply Chain Management of E-Waste for End-of-Life Electronic Products with Reverse Logistics
Authors: Kumar Singh Shubham , Chauhan Anand , Sarkar Biswajit
Published: December 2022

Sustainable development and environmental pollution have become valuable stimulating factors for the resource recovery of end-of-life products through reverse logistics. E-waste is considered in reverse logistics. Electronic waste is solely responsible for environmental hazards and contains valuable raw materials that can be recycled/repaired, so reverse logistics is essential to minimizing their inappropriate disposal. This paper presents the mathematical model for multi-electronic products, considering multi-manufacturers and multi-retailers. After the end-of-life product, the reverse logistics network collects the e-waste in return processors where testing, sorting, and disassembling are carried out and then sent to the repair and recycling units. Components that are not repaired/recycled are shipped to the secondary manufacturer as raw materials. An electronic product’s reverse supply chain is employed to incorporate the idea of e-waste nullification. The fixed point iteration technique is used to solve the proposed model. A numerical example is analyzed to demonstrate the model’s efficacy where the total cost is minimized. The model’s validity and usefulness in reducing e-waste are validated through managerial insights into the model and sensitivity analysis of the key factors. The proposed policy suggests that the e-waste nullification strategy might be a useful apparatus for managers in ensuring long-term sustainability.
Extending the Applicability of Highly Efficient Iterative Methods for Nonlinear Equations and Their Applications
Authors: Behl Ramandeep , Argyros Ioannis K. , Mallawi Fouad Othman , Alharbi Samaher Khalaf
Published: December 2022

Numerous three-step methods of high convergence order have been developed to produce sequences approximating solutions of equations usually defined on the Euclidean space with a finite dimension. The local convergence order is determined by Taylor expansions requiring the existence of derivatives that are not present on the methods. The more interesting semi-local convergence analysis for these methods has not been considered before. The semi-local is also provided based on generalized ω-continuity conditions on the derivative of the operator involved and the majorizing sequences, thus limiting their usage to only solving equations with operators that are many times differentiable. However, these methods may convergence to a solution of the equation even if these high-order derivatives do not exist. That is why a methodology is utilized on two sixth convergence order methods and in the more general setting of a Banach space. This time, the convergence depends only on the operators and the first derivative on the method. Therefore, by this methodology the applicability of the methods is in the extended area. Although this methodology is demonstrated on two competing and efficient methods, it can also be utilized for the same reasons on other methods involving inverses of operators that are linear. This is the motivation and novelty of the paper. The numerical applications further validate the theoretical results both in the local as well as the semi-local convergence case.
Continuous Metaheuristics for Binary Optimization Problems: An Updated Systematic Literature Review
Authors: Becerra-Rozas Marcelo , Lemus-Romani José , Cisternas-Caneo Felipe , Crawford Broderick , Soto Ricardo , Astorga Gino , Castro Carlos , García José
Published: December 2022

For years, extensive research has been in the binarization of continuous metaheuristics for solving binary-domain combinatorial problems. This paper is a continuation of a previous review and seeks to draw a comprehensive picture of the various ways to binarize this type of metaheuristics; the study uses a standard systematic review consisting of the analysis of 512 publications from 2017 to January 2022 (5 years). The work will provide a theoretical foundation for novice researchers tackling combinatorial optimization using metaheuristic algorithms and for expert researchers analyzing the binarization mechanism’s impact on the metaheuristic algorithms’ performance. Structuring this information allows for improving the results of metaheuristics and broadening the spectrum of binary problems to be solved. We can conclude from this study that there is no single general technique capable of efficient binarization; instead, there are multiple forms with different performances.
On the Generalised Transfer Operators of the Farey Map with Complex Temperature
Authors: Bonanno Claudio
Published: December 2022

We consider the problem of showing that 1 is an eigenvalue for a family of generalised transfer operators of the Farey map. This is an important problem in the thermodynamic formalism approach to dynamical systems, which in this particular case is related to the spectral theory of the modular surface via the Selberg Zeta function and the theory of dynamical zeta functions of maps. After briefly recalling these connections, we show that the problem can be formulated for operators on an appropriate Hilbert space and translated into a linear algebra problem for infinite matrices. This formulation gives a new way to study numerically the spectrum of the Laplace–Beltrami operator and the properties of the Selberg Zeta function for the modular surface.
COVID-19 Active Case Forecasts in Latin American Countries Using Score-Driven Models
Authors: Contreras-Espinoza Sergio , Novoa-Muñoz Francisco , Blazsek Szabolcs , Vidal Pedro , Caamaño-Carrillo Christian
Published: December 2022

With the aim of mitigating the damage caused by the coronavirus disease 2019 (COVID-19) pandemic, it is important to use models that allow forecasting possible new infections accurately in order to face the pandemic in specific sociocultural contexts in the best possible way. Our first contribution is empirical. We use an extensive COVID-19 dataset from nine Latin American countries for the period of 1 April 2020 to 31 December 2021. Our second and third contributions are methodological. We extend relevant (i) state-space models with score-driven dynamics and (ii) nonlinear state-space models with unobserved components, respectively. We use weekly seasonal effects, in addition to the local-level and trend filters of the literature, for (i) and (ii), and the negative binomial distribution for (ii). We find that the statistical and forecasting performances of the novel score-driven specifications are superior to those of the nonlinear state-space models with unobserved components model, providing a potential valid alternative to forecasting the number of possible new COVID-19 infections.