bluuebunny/crossref_metadata_2025 huggingface dataset:
Social Security Payments and Financialization: Lessons from the Greek Case
Authors: Kyriakopoulos Dionysios , Yfantopoulos John , Stamatopoulos Theodoros
Published: December 2022

This paper is founded on both the theoretical schemes of financialization, as a new regime of accumulation, and the shareholder value, the everyday finance, the structured finance, as well as the finance-led growth regime, whose special institutional forms concern the wage–labor nexus, the competition form, the monetary regime, the state–society relations, the insertion into the international regime, and the coherence and dynamic of the growth regime. It also aims to examine if the Greek social security system (the “system”) used financial logic in economic policy during the period of 2000q1–2021q3. It is econometrically approached through the short-run Granger causality tests but mainly the autoregressive distributed lag model in order to estimate the long-run relationships of the social contributions and benefits paid, with variables expressing the financialization either of the whole economy or particularly of one of the public sectors. So, these steady-state relationships proved statistically significant, and they are considered to be compatible with several mechanisms of the finance-led growth regime. Thus, the sustainability of the “system” should be insured by the policy makers in the economic progress and the creation of new jobs able to fund it. This article contributes to the literature by offering empirical evidence on the financialization and relevant compilation analysis.
The Relationship between Managers’ Disclosure Tone and the Trading Volume of Investors
Authors: Pouryousof Azam , Nassirzadeh Farzaneh , Hesarzadeh Reza , Askarany Davood
Published: December 2022

The present research investigates the relationship between managers’ disclosure tone and the trading volume of small and large investors separately. The inconsistency of disclosure tone and abnormal trading volume generally indicates information asymmetry between managers and investors. However, by separating the abnormal trading volume of minor investors from major investors, this relationship shows the information asymmetry between minor and major investors. In this research, the disclosure tone of management discussion and analysis (MD&A) is measured using Loughran and McDonald’s (L&M) finance-oriented dictionaries, and tone inconsistency is measured using a benchmark model. The data were collected from 143 companies listed on the Tehran Stock Exchange from 2011 to 2020, totalling 1380 annual reports. The results show that MD&A tone inconsistency positively correlates with abnormal trading volume for all investors. In addition, MD&A tone inconsistency has a different impact on the trading behaviour of small and large investors and misleads the former. The present research contributes to the literature by providing evidence of the relationship between MD&A tone inconsistency and abnormal trading volume of small and major investors. It also uses both common words and word combinations to measure tone.
Historical Floods on the Spanish Mediterranean Basin: A Methodological Proposal for the Classification of Information at High Spatio–Temporal Resolution—AMICME Database (CE 1035–2022)
Authors: Tuset Jordi , Barriendos Mariano , Barriendos Josep
Published: December 2022

The uncertainties raised by climate change in the Mediterranean region justify a detailed study on rainfall regime over a long time scale. This study is not just about reconstructing and characterizing climate variability, but also identifying the hydrometeorological episodes of greater severity and low frequency. These phenomena, such as floods and droughts, affect the availability of water resources, generate casualties and have significant impacts on human activity. In this context of global warming, knowledge of past extreme hydrometeorological events has gained importance over time. Moreover, the ability to classify these past extreme events in order to compare them with current ones strengthens research capabilities. For this reason, this paper proposes a multivariable classification system for flood episodes, both historical and recent. The classification considers the physical conditions of a flood, its damage to structures and its social impacts. The proposed methodology has been applied to the AMICME flood database for the Spanish Mediterranean catchment areas from CE 1035 to 2022. This paper shows the application of this methodology for six flood episodes from different centuries and locations. It has been possible to display all the indexed information for the different flood cases of every episode through cartographic summary representations. Results prove the adaptability of the classification system to different hydrographical and historical contexts.
Rapid Characterisation of Stakeholder Networks in Three Catchments Reveals Contrasting Land-Water Management Issues
Authors: Stosch Kathleen C. , Quilliam Richard S. , Bunnefeld Nils , Oliver David M.
Published: December 2022

Catchments are socio-ecological systems integrating land, water and people with diverse roles and views. Characterising stakeholder networks and their levels of influence and interaction within catchments can help deliver more effective land and water management. In this study, we combined stakeholder analysis and social network methods to provide a novel stakeholder-mapping tool capable of identifying interactions among the land and water management communities across three contrasting study catchments. The overarching aim was to characterise the influence of different stakeholders involved in catchment management based on the perceptions of participants from four key stakeholder groups (Environmental Regulators, Water Industry Practitioners, the Farm Advisor Community, and Academics). A total of 43 participants identified 28 types of specific catchment management stakeholder groups with either core or peripheral importance to our three case study catchments. Participants contributed 490 individual scores relating to the perceived influence of these different stakeholder groups and categorised whether this influence was positive, negative or neutral for the management of catchment resources. Local Government, Farmers and Environmental Regulators were perceived to have the greatest level of influence. Social network analysis further determined which stakeholders were most commonly connected in all of the study catchments and hence formed the core of stakeholder networks in each catchment. Comparing outputs from the analysis of three contrasting river catchments, as well as between participants from four key stakeholder groups allowed identification of which stakeholders were more central to the catchment management networks. Such analyses could help facilitate effective communication within land and water management stakeholder networks by targeting highly connected opinion leaders or promoting peer learning via distinct catchment subgroups.
Coordinated Development of Farmland Transfer and Labor Migration in China: Spatio-Temporal Evolution and Driving Factors
Authors: Wang Yijie , Liu Guoyong , Zhang Bangbang , Liu Zhiyou , Liu Xiaohu
Published: December 2022

The coordinated development of farmland transfer (FT) and labor migration (LM) is of great efficiency significance to facilitate the development of rural economy and implement the rural revitalization strategy. The study used socioeconomic data from 30 provinces/autonomous regions/municipalities (hereafter referred to as provinces) in China to measure the coupling coordination degree (CCD) of FT and LM. It adopted the coupling coordination degree model (CCDM), exploratory spatial data analysis method (ESDA), and gray relational analysis model (GARM) to investigate the spatial differences in the CCD and its influencing factors. The results indicate the following: (1) Regional differences are evident despite the fact that the comprehensive evaluation level of FT and LM in the various provinces is relatively low and displaying a rising trend. (2) The CCD of FT and LM exhibits a fluctuating upward trend and is at the primary coupling coordination stage, with a significant difference in coupling coordination levels between regions, and a spatial distribution pattern of central region > eastern region > northeast region > western region. (3) The CCD shows a strong global spatial positive correlation with clear fluctuations, demonstrating the agglomeration dispersion development tendency over time; the local spatial agglomeration state emerges and stabilizes. According to the distribution pattern, the Western region exhibits weak agglomeration type, whereas the eastern and central regions exhibit strong agglomeration type. (4) There are significant variations between provinces in terms of the intensity of the CCD of FT and LM, as well as the level of concurrent employment business, the level of non-agricultural industry development, the level of urbanization, the level of agricultural equipment, and the land approval.
Short-Term Effects and Vegetation Response after a Megafire in a Mediterranean Area
Authors: Rossetti Ivo , Cogoni Donatella , Calderisi Giulia , Fenu Giuseppe
Published: December 2022

In Mediterranean-climate areas, wildfires have an important ecological role, selecting organisms, influencing species composition and structure of vegetation, and shaping landscapes. However, the increase in frequency and severity of fires can cause, among others, progressive vegetation degradation, biodiversity, and ecosystem services loss. Under the climate change scenario, the frequency and severity of wildfires are expected to increase, especially in the Mediterranean Basin, recognized as among the most affected by the intensification of droughts and heat waves in the future. Therefore, from the perspective of adaptation, it is important not only to assess the sudden effects after a fire but also to investigate the ecological changes and vegetation response over time. In this framework, this study investigates the effects and the short-term vegetation response in an area struck by a megafire. The vegetation response one year after a fire has been assessed in semi-natural grasslands, shrublands, and woodlands at the landscape scale through spectral indices, and at the field scale through floristic and vegetation surveys. Our results showed that after a severe wildfire, although some areas did not exhibit vegetation regrowth, the response of natural vegetation was notable after one year. In the study area, the most resilient vegetation type was semi-natural grasslands, suggesting that this type of vegetation can be crucial for landscape recovery. The other vegetation types showed different response patterns that also prefigure possible changes in species composition and loss of plant diversity over the medium term. This study highlights the value of combining remote sensing spectral analyses and detailed floristic and vegetation surveys for understanding the direction of the early stages of post-fire vegetation dynamics.
The Emerging Role of Ferroptosis in Liver Cancers
Authors: Casini Arianna , Leone Stefano , Vaccaro Rosa , Vivacqua Giorgio , Ceci Ludovica , Pannarale Luigi , Franchitto Antonio , Onori Paolo , Gaudio Eugenio , Mancinelli Romina
Published: December 2022

Liver cancer represents a global health challenge with worldwide growth. Hepatocellular carcinoma (HCC) is the most common type of liver cancer. Indeed, approximately 90% of HCC cases have a low survival rate. Moreover, cholangiocarcinoma (CC) is another malignant solid tumor originating from cholangiocytes, the epithelial cells of the biliary system. It is the second-most common primary liver tumor, with an increasing course in morbidity and mortality. Tumor cells always show high metabolic levels, antioxidant modifications, and an increased iron uptake to maintain unlimited growth. In recent years, alterations in iron metabolism have been shown to play an important role in the pathogenesis of HCC. Several findings show that a diet rich in iron can enhance HCC risk. Hence, elevated iron concentration inside the cell may promote the development of HCC. Growing evidence sustains that activating ferroptosis may potentially block the proliferation of HCC cells. Even in CC, it has been shown that ferroptosis plays a crucial role in the treatment of tumors. Several data confirmed the inhibitory effect in cell growth of photodynamic therapy (PDT) that can induce reactive oxygen species (ROS) in CC, leading to an increase in malondialdehyde (MDA) and a decrease in intracellular glutathione (GSH). MDA and GSH depletion/modulation are crucial in inducing ferroptosis, suggesting that PDT may have the potential to induce this kind of cell death through these ways. A selective induction of programmed cell death in cancer cells is one of the main treatments for malignant tumors; thus, ferroptosis may represent a novel therapeutic strategy against HCC and CC.
Occlusal Splint Therapy Combined with Cranio-Temporomandibular Kinesiotherapy in Patients with Temporomandibular Disorders—A CBCT Study
Authors: Tăut Manuela , Buduru Smaranda Dana , Tălmăceanu Daniel , Ban Alina , Roman Raluca , Leucuța Daniel , Barbur Ioan , Ilea Aranka
Published: December 2022

Occlusal splints are used as a non-invasive treatment for patients diagnosed with temporomandibular disorders (TMD). Another non-invasive treatment option for TMD patients is kinesiotherapy, which may be used alone or in conjunction with occlusal splint therapy. The aim of this study was to evaluate the changes in the intra-articular spaces of the temporomandibular joint (TMJ) after occlusal splint therapy combined with cranio-temporomandibular kinesiotherapy in TMD patients. Twenty-four patients (N = 24) diagnosed with TMD according to Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were included. Cone beam computed tomography (CBCT) images were taken before and after treatment. The anterior, superior, posterior, and medial joint spaces were measured on the CBCT images, and the condylar ratio was calculated using Pullinger and Hollender’s formula. Additionally, the thickness of the glenoid fossa (GFT), condylar medio-lateral widths (MLW), and condylar height (HCo) were measured. The condylar ratio was significantly higher after treatment (p = 0.049). The changes in dimensions of the anterior, superior, posterior and medial joint spaces were not statistically significant after treatment. No statistically significant differences were found in the dimensions of the GFT, MLW, and HCo post treatment. The condylar position did not shift anteriorly in a statistically significant way after occlusal splint therapy combined with cranio-temporomandibular kinesiotherapy in TMD patients.
Platycodon grandiflorus Polysaccharides Alleviate Cr(VI)-Induced Apoptosis in DF-1 Cells via ROS-Drp1 Signal Pathway
Authors: Zhang Zhuanglong , Zheng Pimiao , Qi Changxi , Cui Yuehui , Qi Yijian , Xue Kun , Yan Guangwei , Liu Jianzhu
Published: December 2022

Hexavalent chromium (Cr(VI)) is a widespread heavy metal that has been identified as a human carcinogen, and acute or chronic exposure to Cr(VI) can cause organ damage. Platycodon grandiflorus polysaccharide (PGPS) is a constituent extracted from the Chinese herb Platycodon grandiflorus, which has various pharmacological effects. Therefore, the author investigated the role of PGPSt in Cr(VI)-induced apoptosis in chicken embryo fibroblast cell lines (DF-1 cells). Firstly, this study infected DF-1 cells using Cr(VI) to set up a model for cytotoxicity and then added PGPSt. Then, the intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and apoptosis rate were evaluated. The results showed that PGPSt could inhibit Cr(VI)-induced mitochondrial damage and increase the apoptosis rate. For further exploration of the mechanism of regulation of PGPSt, the ROS-Drp1 pathway was investigated. The antioxidant N-acetyl-L-cysteine (NAC) and mitochondrial division inhibitor 1(Mdivi-1) were added, respectively. The results showed that the NAC and Mdivi-1 restored abnormal mitochondrial fission and cell apoptosis. Thus, PGPSt can alleviate Cr(VI)-induced apoptosis of DF-1 cells through the ROS-Drp1 signaling pathway, which may suggest new research ideas for developing new drugs to alleviate Cr(VI) toxicity.
Non-Aerated Common Nettle (Urtica dioica L.) Extract Enhances Green Beans (Phaseolus vulgaris L.) Growth and Soil Enzyme Activity
Authors: Maričić Branka , Brkljača Mia , Ban Dean , Palčić Igor , Franin Kristijan , Marcelić Šime , Goreta Ban Smiljana
Published: December 2022

One of the limiting factors in organic farming is the scarcity of allowed fertilizers and chemicals for plant protection. Plant and compost extracts are a promising solution for fertilization because of their positive effect on plant growth and soil microbial activity. Nettle extract was already successfully applied to some vegetables. Not-aerated nettle extract, obtained from dry nettle leaves, was applied in experiments with green beans in a quantity of 1 L per pot at two-day intervals was studied. A three-factorial experimental design was applied with two soil types (brown—Calcic Gleysol and red—Eutric Cambisol), soil disinfection with dazomet or not, and irrigated with nettle extract or water. Nettle extract application increased all above-ground traits; plant height, leaf area, flower buds, shoot dry weight at flowering, pod length, pod diameter, and shoot dry weight at harvest by 49%, 66%, 43%, 36%, 11%, 9%, and 37%, respectively, the root length at harvest by 59%, total yield by 48%, soil respiration by 91% and 74% in two soil types, and alkaline phosphatase by 30%. Dehydrogenase activity was enhanced by nettle extract application on red soil, while nettle extract application had no effect on root nodulation. The nettle extract application benefits in green bean organic production were attributed to the nutrients and other components present in the extract and not to nitrogen fixation. The optimization of the dose of the extract and experiments in real conditions of green bean production would be the next step toward the implementation of nettle extract as an organic fertilizer.
Modified Ni Nanoparticles as Additives in Various Greases: Assessment of Comparative Performance Potential
Authors: Wang Jiabei , Zhang Hong , Hu Wenjing , Li Jiusheng
Published: December 2022

China’s rapid industrial development requires more energy consumption based on non-renewable energy resources. The energy consumption caused by unnecessary friction accounts for about 4.5% of the GDP in China. Although grease effectively lubricates machines, lubrication failure may occur under severe conditions. Nanomaterials exhibit intriguing tribological performances and have received much attention regarding lubrication. In this study, oleylamine-modified Ni nanoparticles (OA-Ni) were synthesized and used as lubricant additive in four kinds of commonly used greases: lithium, calcium, composite calcium, and polyurea grease. The OA-Ni were uniformly dispersed in the greases through electromagnetic stirring, ultrasonic vibration, and three-roll grinding. The physicochemical properties and the structure of OA-Ni-doped grease were investigated, while the feasibility of OA-Ni as various grease additives at different contact modes was evaluated by a four-ball friction tester and a UMT-tribolab tester. Tribological tests results revealed that the friction-reducing and anti-wear properties of point-to-point contact were increased by 56.7% and 70.3% in lithium grease, respectively, while those of the point-to-face contact were increased by 59.5% and 68.9% in polyurea grease, respectively. The present work provides not only theoretical guidance of nano nickel modification but also a practical reference for the application of modified nanomaterials to various greases.
Reliability Analysis of Concrete Beam with High-Strength Steel Reinforcement
Authors: Zhang Feiyan , Feng Fan , Liu Xiang
Published: December 2022

In concrete structures, replacing conventional steel bars with high-strength steel reinforcement (HSSR) can effectively save the use of materials. However, the deformation properties and strength dispersion of HSSR are different from those of conventional steel reinforcement, which restricts or conservatively uses them in practical applications. For example, the partial safety factor of HRB500 grade steel bars (the yield strength is 500 MPa) in guideline GB50010-2010 is larger than that of conventional steel bars, and there is no relevant guidance for HRB600 grade steel bars (the yield strength is 600 MPa). Based on this, this paper will propose the limit state design method of high-strength steel reinforced concrete beam (HSSRCB) based on reliability analysis, which is convenient for the popularization and use of HSSR. Firstly, the flexural performance test of HSSRCBs was introduced, and the flexural capacity of HSSRCB was analyzed based on the existing prediction model. Second, a sectional numerical analysis model was established, where the section was discretized into several points, and then the curvature was gradually increased to obtain the corresponding bending moment through integration. A large number of samples were calculated to obtain statistical characteristics of the error of prediction model. Then, the limit state functions were established for two kinds of format, including partial safety factor format (PSSF) and resistance reduction factor format (RRFF), respectively, and the reliability of HSSRCBs was analyzed based on Monte Carlo simulation. Finally, the recommended values of partial safety factor of material and reduction factor of bearing capacity were proposed, in which the design strength of HRB500 and HRB600 reinforcement was 454 MPa and 545 MPa for PSSF, respectively, and the resistance reduction factor for the flexural capacity of HSSRCB was 0.8 and 0.75 for RRFF, respectively.
Assessment of Corrosion Resistance and Hardness of Shot Peened X5CrNi18-10 Steel
Authors: Walczak Mariusz , Szala Mirosław , Okuniewski Wojciech
Published: December 2022

Although the application of shot peening facilitates increasing hardness and corrosion resistance of stainless steel, the inappropriate peening parameters result in overestimated hardening and exaggerated surface roughness, which deteriorate the surface morphology and negatively affect the corrosive behavior of treated steel. Therefore it is crucial to select the peening parameters that allow obtaining both high hardness and elevated corrosion resistance. This study aims to determine the effect of X5CrNi18-10 stainless steel samples shot peening on the surface morphology, hardness, and corrosion resistance. Samples were shot peened with a CrNi steel shot, applying 0.3 MPa and 0.4 MPa peening pressures and treatment times of 60 s and 120 s. Roughness analysis and microscopic and SEM-EDS examination were employed to state the effect of peening parameters on the sample’s corrosive behavior in a 3.5% NaCl solution. The most promising shot peening parameters for Vickers hardness and electrochemical corrosion resistance were selected. It is revealed that the surface roughness increase has a detrimental effect on the corrosion behavior. Overall, high corrosion resistance and the high hardness of stainless steel samples were noted for the peening pressure of 0.4 MPa and time treatment of 60 s.
Density-Controlled Growth of ZnO Nanowalls for High-Performance Photocatalysts
Authors: Chang Yu-Cheng , Lin Ying-Ru , Chen Sheng-Wen , Chou Chia-Man
Published: December 2022

ZnO nanowires and nanowalls can be fabricated on the glass substrate with a ZnO seed film and low-cost aluminum (Al) foil by the aqueous solution method (ASM), respectively. The different concentrations of ZnO precursors can use to control the densities of ZnO nanowalls. In addition, FESEM, FETEM, EDS, XRD, XPS, and CL were used to evaluate the characteristics of ZnO nanowalls. The ZnO nanowalls exhibited higher photocatalytic efficiency (99.4%) than that of ZnO nanowires (53.3%) for methylene blue (MB) degradation under UVC light irradiation at the ZnO precursors of 50 mM. This result is attributed to ZnO nanowalls with Al-doped, which can improve the separation of photogenerated electron-hole pairs for enhanced photocatalytic activity. In addition, ZnO nanowalls can also reveal higher photocatalytic activity for the degradation of tetracycline capsules (TC) rather than commercial ZnO nanopowder under UVC light irradiation. The superoxide and hydroxyl radicals play essential roles in the degradation of MB and TC solutions by the radical-trapping experiment. Furthermore, the ZnO nanowalls exhibit excellent recycling and reuse capacity for up to four cycles for the degradation of MB and TC. This study highlights the potential use of ZnO nanowalls directly grown on commercial and low-cost Al foil as noble metal-free photocatalysis.
Study on Bond Performance between Corroded Deformed Steel Bar and DS-ECC
Authors: Liu Tongwei , Li Xinping , Che Jialing
Published: December 2022

In order to study the bond performance between desert sands engineered cementitious composites (DS-ECC) and corrosion steel bars, seven groups of specimens were designed and manufactured. Through the center pull-out test, the effects of different types of desert sands, the rate of corrosion (0, 5, 10 and 15%), and the anchorage length of steel bars (5d and 8d) on the bonding properties of DS-ECC and corrosion steel bars were studied. Moreover, a de-rusting agent was used to remove the corrosion, and three groups of specimens were pulled out from the center of the de-rusted steel bars. The results showed that both Tengger DS-ECC and Mu Us DS-ECC have good bond properties with corrosion steel bars. The bond stress slip curves between DS-ECC and corrosion steel bars can be divided into four stages: the micro-slip, slip stage, failure stage and residual stage. The bond stress slip curves between DS-ECC and de-rusted steel bars can be divided into the micro-slip stage, failure stage and residual stage, and splitting and pulling-out failure occurs in DS-ECC specimens. The ultimate bond strength is the highest when the corrosion rate is 5%. The bond toughness index is positively correlated with the anchorage length of steel bars, and negatively correlated with the corrosion rate of steel bars. According to the test results, the bond–slip mathematical relationship is established.
Determining the Mechanical Properties of Solid Plates Obtained from the Recycling of Cable Waste
Authors: Wędrychowicz Maciej , Papacz Władysław , Walkowiak Janusz , Bydałek Adam , Piotrowicz Andrzej , Skrzekut Tomasz , Kurowiak Jagoda , Noga Piotr , Kostrzewa Mirosław
Published: December 2022

In this article, the possibility of obtaining a solid plate from waste cable sheaths, by mechanical recycling, i.e., grinding, plasticising and pressing, is discussed—waste cable sheaths being pure PVC with a slight admixture of silicone. Press moulding was carried out under the following conditions: temperature 135 °C, heating duration 1 h and applied pressure 10 MPa. The yield point of the obtained solid plate obtained was 15.0 + −0.6 MPa, flexural strength 0.94 MPa, yield point 0.47 MPa and Charpy’s impact strength 5.1 kJ/m2. The resulting solid plate does not differ significantly from the input material, in terms of mechanical strength, so, from the point of view of strength, that is, from a technical point of view, such promising processing of waste cables can be carried out successfully in industrial practice.
Application of Artificial Neural Networks to the Analysis of Friction Behaviour in a Drawbead Profile in Sheet Metal Forming
Authors: Trzepieciński Tomasz , Najm Sherwan Mohammed
Published: December 2022

Drawbeads are used when forming drawpieces with complex shapes to equalise the flow resistance of a material around the perimeter of the drawpiece or to change the state of stress in certain regions of the drawpiece. This article presents a special drawbead simulator for determining the value of the coefficient of friction on the drawbead. The aim of this paper is the application of artificial neural networks (ANNs) to understand the effect of the most important parameters of the friction process (sample orientation in relation to the rolling direction of the steel sheets, surface roughness of the counter-samples and lubrication conditions) on the coefficient of friction. The intention was to build a database for training ANNs. The friction coefficient was determined for low-carbon steel sheets with various drawability indices: drawing quality DQ, deep-drawing quality DDQ and extra deep-drawing quality EDDQ. Equivalents of the sheets tested in EN standards are DC01 (DQ), DC03 (DDQ) and DC04 (EDDQ). The tests were carried out under the conditions of dry friction and the sheet surface was lubricated with machine oil LAN46 and hydraulic oil LHL32, commonly used in sheet metal forming. Moreover, various specimen orientations (0° and 90°) in relation to the rolling direction of the steel sheets were investigated. Moreover, a wide range of surface roughness values of the counter-samples (Ra = 0.32 μm, 0.63 μm, 1.25 μm and 2.5 μm) were also considered. In general, the value of the coefficient of friction increased with increasing surface roughness of the counter-samples. In the case of LAN46 machine oil, the effectiveness of lubrication decreased with increasing mean roughness of the counter-samples Ra = 0.32–1.25 μm. With increasing drawing quality of the sheet metal, the effectiveness of lubrication increased, but only in the range of surface roughness of the counter-samples in which Ra = 0.32–1.25 μm. This study investigated different transfer functions and training algorithms to develop the best artificial neural network structure. Backpropagation in an MLP structure was used to build the structure. In addition, the COF was calculated using a parameter-based analytical equation. Garson partitioning weight was used to calculate the relative importance (RI) effect on coefficient of friction. The Bayesian regularization backpropagation (BRB)—Trainbr training algorithm, together with the radial basis normalized—Radbasn transfer function, scored best in predicting the coefficient of friction with R2 values between 0.9318 and 0.9180 for the training and testing datasets, respectively.
Structural, Chemical and Magnetic Characterization of Quartz Sand from Cluj Area, Romania for Future Beneficiation in the Glass Industry
Authors: Popa Florin , Marinca Traian Florin , Neamțu Bogdan Viorel , Gabor Mihai , Chicinaş Ionel
Published: December 2022

For use in crystal glass production, quartz sand must contain less than 0.09% iron. If the sand contains more than 0.09% Fe, the iron must be removed. In the present study, quartz sand from tailings ponds near the Cluj area of Romania is analyzed for potential use in the glass industry, after magnetic separation. The particle size distribution of raw sand was determined, and mineralogical analyses was realized. Using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), morphology and elemental distribution maps on the particle was performed. The evolution of the iron content versus the particle size was analyzed. Using X-ray diffraction, the phases occurring in the sand were investigated in relation to the particle size. Magnetic separation with two magnets, having different energy, was performed for identifying the phases attached to the magnetic particles. Magnetic hysteresis measurements evidenced complex and multiple iron phase behavior.
Analysis of Unconfined Compressive Strength of Rammed Earth Mixes Based on Artificial Neural Network and Statistical Analysis
Authors: Mustafa Yassir Mubarak Hussein , Zami Mohammad Sharif , Al-Amoudi Omar Saeed Baghabra , Al-Osta Mohammed A. , Wudil Yakubu Sani
Published: December 2022

Earth materials have been used in construction as safe, healthy and environmentally sustainable. It is often challenging to develop an optimum soil mix because of the significant variations in soil properties from one soil to another. The current study analyzed the soil properties, including the grain size distribution, Atterberg limits, compaction characteristics, etc., using multilinear regression (MLR) and artificial neural networks (ANN). Data collected from previous studies (i.e., 488 cases) for stabilized (with either cement or lime) and unstabilized soils were considered and analyzed. Missing data were estimated by correlations reported in previous studies. Then, different ANNs were designed (trained and validated) using Levenberg-Marquardt (L-M) algorithms. Using the MLR, several models were developed to estimate the compressive strength of both unstabilized and stabilized soils with a Pearson Coefficient of Correlation (R2) equal to 0.2227 and 0.766, respectively. On the other hand, developed ANNs gave a higher value for R2 than MLR (with the highest value achieved at 0.9883). Thereafter, an experimental program was carried out to validate the results achieved in this study. Finally, a sensitivity analysis was carried out using the resulting networks to assess the effect of different soil properties on the unconfined compressive strength (UCS). Moreover, suitable recommendations for earth materials mixes were presented.
Investigation of the Effect of ECAP Parameters on Hardness, Tensile Properties, Impact Toughness, and Electrical Conductivity of Pure Cu through Machine Learning Predictive Models
Authors: Shaban Mahmoud , Alsharekh Mohammed F. , Alsunaydih Fahad Nasser , Alateyah Abdulrahman I. , Alawad Majed O. , BaQais Amal , Kamel Mokhtar , Nassef Ahmed , El-Hadek Medhat A. , El-Garaihy Waleed H.
Published: December 2022

Copper and its related alloys are frequently adopted in contemporary industry due to their outstanding properties, which include mechanical, electrical, and electronic applications. Equal channel angular pressing (ECAP) is a novel method for producing ultrafine-grained or nanomaterials. Modeling material design processes provides exceptionally efficient techniques for minimizing the efforts and time spent on experimental work to manufacture Cu or its associated alloys through the ECAP process. Although there have been various physical-based models, they are frequently coupled with several restrictions and still require significant time and effort to calibrate and enhance their accuracies. Machine learning (ML) techniques that rely primarily on data-driven models are a viable alternative modeling approach that has recently achieved breakthrough achievements. Several ML algorithms were used in the modeling training and testing phases of this work to imitate the influence of ECAP processing parameters on the mechanical and electrical characteristics of pure Cu, including the number of passes (N), ECAP die angle (φ), processing temperature, and route type. Several experiments were conducted on pure commercial Cu while altering the ECAP processing parameters settings. Linear regression, regression trees, ensembles of regression trees, the Gaussian process, support vector regression, and artificial neural networks are the ML algorithms used in this study. Model predictive performance was assessed using metrics such as root-mean-squared errors and R2 scores. The methodologies presented here demonstrated that they could be effectively used to reduce experimental effort and time by reducing the number of experiments runs required to optimize the material attributes aimed at modeling the ECAP conditions for the following performance characteristics: impact toughness (IT), electrical conductivity (EC), hardness, and tensile characteristics of yield strength (σy), ultimate tensile strength (σu), and ductility (Du)
Comparative Study on Carbon Erosion of Nickel Alloys in the Presence of Organic Compounds under Various Reaction Conditions
Authors: Volodin Alexander M. , Kenzhin Roman M. , Bauman Yury I. , Afonnikova Sofya D. , Potylitsyna Arina R. , Shubin Yury V. , Mishakov Ilya V. , Vedyagin Aleksey A.
Published: December 2022

The processes of carbon erosion of nickel alloys during the catalytic pyrolysis of organic compounds with the formation of carbon nanofibers in a flow-through reactor as well as under reaction conditions in a close volume (Reactions under Autogenic Pressure at Elevated Temperature, RAPET) were studied. The efficiency of the ferromagnetic resonance method to monitor the appearance of catalytically active nickel particles in these processes has been shown. As found, the interaction of bulk Ni-Cr alloy with the reaction medium containing halogenated hydrocarbons (1,2-dichloroethane, 1-iodobutane, 1-bromobutane) results in the appearance of ferromagnetic particles of similar dimensions (~200–300 nm). In the cases of hexachlorobenzene and hexafluorobenzene, the presence of a hydrogen source (hexamethylbenzene) in the reaction mixture was shown to be highly required. The microdispersed samples of Ni-Cu and Ni-Mo alloys were prepared by mechanochemical alloying of powders and by reductive thermolysis of salts-precursors, accordingly. Their interaction with polymers (polyethylene and polyvinyl chloride) under RAPET conditions and with ethylene and 1,2-dichloroethane in a flow-through reactor are comparatively studied as well. According to microscopic data, the morphology of the formed carbon nanofibers is affected by the alloy composition and by the nature of the used organic substrate.
The Optimization of Mechanical Alloying Conditions of Powder for the Preparation of a Fe-10Al-4Cr-4Y2O3 ODS Nanocomposite
Authors: Svoboda Jiří , Gamanov Štepán , Bártková Denisa , Luptáková Natália , Bořil Petr , Jarý Milan , Mašek Bohuslav , Holzer Jakub , Dymáček Petr
Published: December 2022

Mechanical alloying (MA) of powders represents the first processing step in the production of oxide dispersion-strengthened (ODS) alloys. MA is a time and energy-consuming process also in the production of Fe-10Al-4Cr-4Y2O3 creep and oxidation-resistant ODS nanocomposite, denoted as the FeAlOY, and it deserves to be optimized. MA is performed at two different temperatures at different times. The powder after MA, as well as the microstructure and high-temperature strength of the final FeAlOY, are characterized and the optimal MA conditions are evaluated. The obtained results show that the size distribution of the powder particles, as well as the dissolution and homogenization of the Y2O3, becomes saturated quite soon, while the homogenization of the metallic components, such as Al and Cr, takes significantly more time. The high-temperature tensile tests and grain microstructures of the secondary recrystallized FeAlOY, however, indicate that the homogenization of the metallic components during MA does not influence the quality of the FeAlOY, as the matrix of the FeAlOY is sufficiently homogenized during recrystallization. Thus, the conditions of MA correspond to sufficient dissolution and homogenization of Y2O3 and can be considered the optimal ones.
The Influence of a Binder in a Composite Electrode: The Case Study of Vanadyl Phosphate in Aqueous Electrolyte
Authors: Jugović Dragana , Milović Miloš D. , Barudžija Tanja , Kuzmanović Maja , Vujković Milica , Mitrić Miodrag
Published: December 2022

Layered VOPO4·2H2O is synthesized by the sonochemical method. An X-ray powder diffraction is used to examine the crystal structure, while scanning electron microscopy is used to reveal the morphology of the powder. The crystal structure refinement is performed in the P4/nmmZ space group. The electrochemical intercalation of several cations (Na+, Mg2+, Ca2+, and Al3+) in saturated nitrate aqueous solutions is investigated. The most notable reversible activity is found for the cycling in aluminium nitrate aqueous solution in the voltage range from −0.1 to 0.8 V vs. SCE. During the preparation of the electrode, it is observed that the structure is prone to changes that have not been recorded in the literature so far. Namely, the use of conventional binder PVDF in NMP solution deteriorates the structure and lowers the powder’s crystallinity, while the use of Nafion solution causes the rearrangement of the atoms in a new crystal form that can be described in the monoclinic P21/c space group. Consequently, these structural changes affect electrochemical performances. The observed differences in electrochemical performances are a result of structural rearrangements.
Mechanical Properties of Fly Ash-Based Geopolymer Concrete Incorporation Nylon66 Fiber
Authors: Yazid Muhd Hafizuddin , Faris Meor Ahmad , Abdullah Mohd Mustafa Al Bakri , Ibrahim Muhammad Shazril I. , Razak Rafiza Abdul , Burduhos Nergis Dumitru Doru , Burduhos Nergis Diana Petronela , Benjeddou Omrane , Nguyen Khanh-Son
Published: December 2022

This study was carried out to investigate the effect of the diamond-shaped Interlocking Chain Plastic Bead (ICPB) on fiber-reinforced fly ash-based geopolymer concrete. In this study, geopolymer concrete was produced using fly ash, NaOH, silicate, aggregate, and nylon66 fibers. Characterization of fly ash-based geopolymers (FGP) and fly ash-based geopolymer concrete (FRGPC) included chemical composition via XRF, functional group analysis via FTIR, compressive strength determination, flexural strength, density, slump test, and water absorption. The percentage of fiber volume added to FRGPC and FGP varied from 0% to 0.5%, and 1.5% to 2.0%. From the results obtained, it was found that ICBP fiber led to a negative result for FGP at 28 days but showed a better performance in FRGPC reinforced fiber at 28 and 90 days compared to plain geopolymer concrete. Meanwhile, NFRPGC showed that the optimum result was obtained with 0.5% of fiber addition due to the compressive strength performance at 28 days and 90 days, which were 67.7 MPa and 970.13 MPa, respectively. Similar results were observed for flexural strength, where 0.5% fiber addition resulted in the highest strength at 28 and 90 days (4.43 MPa and 4.99 MPa, respectively), and the strength performance began to decline after 0.5% fiber addition. According to the results of the slump test, an increase in fiber addition decreases the workability of geopolymer concrete. Density and water absorption, however, increase proportionally with the amount of fiber added. Therefore, diamond-shaped ICPB fiber in geopolymer concrete exhibits superior compressive and flexural strength.
High Temperature Performance of Concrete Confinement by MWCNT Modified Epoxy Based Fiber Reinforced Composites
Authors: Joseph Lakshmi , Madhavan Mini K. , Jayanarayanan Karingamanna , Pegoretti Alessandro
Published: December 2022

The conventional method of fiber reinforced polymer (FRP) wrapping around concrete columns uses epoxy as the binder along with synthetic or natural fibers such as carbon, glass, basalt, jute, sisal etc. as the reinforcement. However, the thermal stability of epoxy is a major issue in application areas prone to fire exposure. The current work addressed this major drawback of epoxy by modifying it with a nanofiller, such as multiwalled carbon nanotubes (MWCNT), and reinforcing it using basalt and sisal fibers. The effect of exposure to elevated temperature on the behavior of concrete cylinders externally confined with these FRP systems was analyzed. Three types of specimens were considered: unconfined; confined with sisal fiber reinforced polymer (SFRP); and confined with hybrid sisal basalt fiber reinforced polymer (HSBFRP) specimens. The test samples were exposed to elevated temperature regimes of 100 °C, 200 °C, 300 °C and 400 °C for a period of 2 h. The compressive strengths of unconfined specimens were compared with various confined specimens, and from the test results, it was evident that the mechanical and thermal durability of the FRP systems was substantially enhanced by MWCNT incorporation. The reduction in the compressive strength of the FRP-confined specimens varied depending on the type of the confinement. After two hours of exposure at 400 °C, the compressive strength corresponding to the epoxy–HSBFRP-confined specimens were improved by 15%, whereas a 50% increase in strength corresponding to MWCNT-incorporated epoxy–HSBFRP-confined specimens was observed with respect to unconfined unexposed specimens. The MWCNT-modified epoxy-incorporated FRP-confined systems demonstrated superior performance even at elevated temperatures in comparison to unconfined specimens at ambient temperatures.
All-Natural Moss-Based Microstructural Composites in Deformable Form for Use as Graffiti and Artificial-Porous-Material Replacement
Authors: Kim Bu-Gon , Yoon Min-Ho , Kim Jaehwan , Oh Jung-Hwan
Published: December 2022

Although artificial porous materials are useful for dissipating acoustic waves, they pose a major environmental threat as most are non-recyclable. Developing sustainable structural materials with the mechanical and energy-absorption properties required to replace artificial porous materials is currently a key challenge. Here, we report, for the first time, a novel microstructure using all-natural moss with a compressive strength of up to 2.35 GPa and a sound-absorption performance of up to 90%, depending on the additives, such as yogurt, starch, and beer. In addition, the moss-based microstructure was applied as graffiti to a three-dimensionally printed house model to demonstrate improved performance against the effects of sound. By incorporating energy-absorbing materials without harmful substances, the desired structure can be decorated with the graffiti method. This work could pave the way for attenuating sound-wave and impact noise by using graffiti work on structural composite materials.
Environmental Risk Analysis Based on Characterization of Ground Oily Sludge
Authors: Zhang Shifan , Wu Jiwei , Nie Qi , Duan Xiaoxu , Yi Xianzhong
Published: December 2022

Oily sludge is recognized as hazardous waste. To reduce the potential danger and harmful factors of oily sludge, it is very important to analyze its environmental risk. In this paper, the characterization of oily sludge from Shengli Oilfield in China was tested experimentally, including the composition content, particle size, microscopic morphology, heavy metal content, organic composition, inorganic composition, and thermogravimetric analysis, which were used to analyze environmental risks. The results show that the oil content of oily sludge is as high as 10.3%, which will cause serious pollution. It is calculated that China can recover 772.5 million liters of oil and reduce 553.9 million kg of carbon emissions compared with incineration in one year, if the oily sludge can be managed effectively. The content of heavy metals such as Ba, Zn, Cr, As, Ni, Se, Be, and Hg in oily sludge exceeds the standard. It will restrain the self-healing ability of soil, pollute groundwater, and endanger animals and plants. The organic matter of oily sludge is concentrated in C11 to C29. It contains a large amount of benzene series and polycyclic benzene hydrocarbons, which can lead to cancer in the human body. Inorganic substances in oily sludge are mixed with some additives, which can not only reduce the toxicity of heavy metals, but also be used as building materials. The median particle size D50 of oily sludge is 0.91 μm, and it spreads all over the narrow pores. Generally, it needs to be treated under high temperature conditions, which will cause secondary pollution to the environment. The research content of this paper provides a theoretical reference for the management of oily sludge.