bluuebunny/crossref_metadata_2025 huggingface dataset:
The Resilience of Diversified Clusters: Reconfiguring Commodity Networks in Rural China during the COVID-19 Pandemic
Authors: Hu Zhanping , Zhang Qian Forrest
Published: March 2022

We conceptualize typical rural communities in China as diversified economic clusters. In normal times, economic actors in these communities rarely cooperate with each other, but are integrated into separate commodity chains. These “diversified clusters”, however, show resilience and flexibility when an external shock—the COVID-19 pandemic—disrupts the spatial connections throughout the existing commodity chains. In this study, we use primary field data collected from one typical rural community in Northern China to show how economic diversity, aided by social networks and space-shrinking technologies, allowed for the vertical commodity chains to be reconfigured temporarily into localized horizontal commodity networks to cope with the emergencies brought about by the pandemic. Our findings suggest that while market integration can create precarity at the individual level, it can also contribute to economic resilience at the community level if it increases economic diversity and complementarity within the community. This study sheds lights on discussions of the resilience of rural and economic clustering by a novel conceptualization of diversified clusters and also offers a nuanced understanding of the connection between market integration and community resilience.
Evaluating Perceptions towards the Consequential Validity of Integrated Language Proficiency Assessment
Authors: Gokturk Saglam Asli Lidice , Tsagari Dina
Published: March 2022

This research study explores teacher and student perceptions to verify consequential validity and the potential washback effect of a locally developed university-level English language proficiency test which consists of reading and listening-to-writing assessment tasks. The integrated language proficiency test is used upon completion of the English language preparatory program in the Turkish context to determine learners’ access to further English medium academic courses in their departments. To examine whether this source-based proficiency test has achieved its intended outcomes, 39 freshman students and 19 university instructors, who offered courses in various departments, were surveyed through questionnaires. Interviews were conducted with the instructors to gauge their perspectives about the validity of the integrated proficiency test-based decisions (whether students pass or fail) over time in terms of the language competency and academic skills of their learners. Quantitative and qualitative data analysis also revealed evidence both for positive and negative issues concerning the consequential validity of the test. Findings may help educators to reach a better understanding of the construct of integrated language assessment tasks in EAP contexts and the consequences of their use in achieving the intended and unintended curricular goals.
Lubricating Oil Consumption Measurement on Large Gas Engines
Authors: Rossegger Bernhard , Leis Albrecht , Vareka Martin , Engelmayer Michael , Wimmer Andreas
Published: March 2022

Increasing the reliability of combustion engines while further reducing emissions and life cycle costs are the main drivers for optimizing lubricating oil consumption (LOC). However, in order to reduce the lube oil consumption of an engine, it is crucial to measure it accurately. Therefore, a LOC measurement device based on the use of the stable isotope deuterium has been developed. Previous publications have focused on the use of passenger car engines. This publication describes the first application of this newly developed method on a large gas engine. This is of particular interest as large-bore engines might show different oil consumption behavior, much higher LOC in gram per hour and the bigger oil reservoir need larger amounts of tracer. Additionally, a different type of fuel has an effect on oil consumption measurement as well, as presented in this paper. The results showed this method can be applied to large gas engines as well after conducting minor changes to the measurement setup. However, other than liquid fuels, the origin and isotopic composition of the natural gas has to be monitored. Ideally, gas from large storage is used for carrying out these measurements.
Synthesis of New 1,2,3,4-Tetrahydroquinoline Hybrid of Ibuprofen and Its Biological Evaluation
Authors: Manolov Stanimir , Ivanov Iliyan , Bojilov Dimitar
Published: March 2022

Herein we report the obtaining of 1-(3,4-dihydroquinolin-1(2H)-yl)-2- (4-isobutylphenyl)propan-1-one and its characterization. The newly obtained hybrid and its derivatives (hybrids of ibuprofen with 1,2,3,4-tetrahydroisoquinoline, and piperidine) were screened for their in vitro antioxidant, antitryptic, and inhibition of albumin denaturation activity. The lipophilicity was established using both reversed-phase thin layer chromatography and in silico calculations.
2-Bromo-3-((1-(7-chloroquinolin-4-yl)-1H-1,2,3-triazol-4-yl)-methoxy)-benzaldehyde
Authors: Yun Xiaoyun , Xie Yuhan , Ng Jerome P. L. , Law Betty Yuen Kwan , Wong Vincent Kam Wai , Coghi Paolo
Published: March 2022

The 1,2,3-triazole ring system can be easily obtained by copper-catalyzed click reaction of azides with alkynes. 1,2,3-Triazole exhibits a myriad of biological activities, including antimalarial, antibacterial, and antiviral activities. We herein reported the synthesis of quinoline-based [1,2,3]-triazole hybrid via Cu(I)-catalyzed click reaction of 4-azido-7-chloroquinoline with alkyne derivative of 2-bromobenzaldehyde. The compound was fully characterized by proton nuclear magnetic resonance (1H-NMR), carbon-13 nuclear magnetic resonance (13C-NMR), heteronuclear single quantum coherence (HSQC), ultraviolet (UV), and high-resolution mass spectroscopies (HRMS). This compound was screened in vitro against two different normal cell lines. Preliminary studies attempted to evaluate its interaction with Delta RBD of spike protein of SARS-CoV-2 by bio-layer interferometry. Finally, the drug-likeness of the compound was also investigated by predicting its pharmacokinetic properties.
In Silico Evaluation of a Promising Key Intermediate Thieno [2,3-d] Pyrimidine Derivative with Expected JAK2 Kinase Inhibitory Activity
Authors: Elmongy Elshaymaa , Henidi Hanan
Published: March 2022

This work describes the synthesis and the cytotoxic evaluation of thiophene and thienopyrimidine derivatives. The investigated compound was subjected to target prediction that indicated its high affinity to kinases and to Janus kinase 2 (JAK2) specifically. Molecular docking screening was performed on three different JAK2 proteins downloaded from the Protein Data Bank (PDB: 5AEP, 4C62 and 3ZMM). In vitro kinase inhibitory activity was evaluated and then compound cytotoxicity was performed on three different cancerous cell lines (HT-29, HepG-2, and MCF-7). Marked cytotoxic activity of the thienopyrimidine derivative against the HepG-2 cell line was demonstrated, reflected by its IC50 value of 8.001 ± 0.0445 μM, which is better than that of the reference standard (IC50 13.91 ± 2.170 μM). Pharmacokinetic studies revealed good well permeability and GI absorption with no violations against Lipinski’s rule.
Mineralogical Characteristics and Luminescent Properties of Natural Fluorite with Three Different Colors
Authors: Ge Xiao , Guo Qingfeng , Wang Qianqian , Li Tao , Liao Libing
Published: March 2022

Fluorite is rich in mineral resources and its gorgeous colors and excellent luminescence characteristics have attracted the attention of many scholars. In this paper, the composition, structure, luminescent properties, and the potential application value of three fluorites with different colors and are systematically analyzed. The results show that REE and radioactive elements have effects on the structure, color, and luminescence of fluorite. Radioactive elements Th and U will aggravate the formation of crystal defects in fluorite. The green color is related to Ce3+ and Sm2+. Colloidal calcium and F− center are responsible for the blue-purple color of fluorite. There are many luminescent centers, such as Eu, Pr, Dy, Tb, Er, and Sm, in fluorite. The blue fluorescence is mainly caused by 4f7-4f65d1 of Eu2+. In addition, it is found that fluorite has certain temperature sensing properties in the temperature range of 303–343 K.
Morphological Evolution of TiB2 and TiAl3 in Al–Ti–B Master Alloy Using Different Ti Adding Routes
Authors: Zhao Yanjun , Lu Zepeng , Mi Li , Hu Zhiliu , Yang Wenchao
Published: March 2022

Three different Ti addition routes were used to prepare an Al–5Ti–B Master Alloy: the halide salt route, the Ti-sponge route, and the partial Ti-sponge route. In the halide salt route, the raw materials were Al + KBF4 + K2TiF6; K2TiF6 was completely replaced by pure titanium for the Ti-sponge route versus the halide salt route; in the partial Ti-sponge route, K2TiF6 was partially replaced by pure titanium. Here, 30% Ti-sponge or 60% Ti-sponge route means that 30% or 60% K2TiF6 was replaced by pure titanium, respectively. The above Ti addition routes have a significant influence on the growth pattern and morphological evolution of TiAl3 and TiB2, which greatly affect the refining performance of Al–Ti–B Master Alloy. When using the halide salt route, a streamlined “rich Ti, B area” exists in the aluminum melt, which is a complex compound of (Tix, Al1−x) By. The “rich Ti, B area” is essential for the nucleation and growth of TiAl3 and TiB2. Blocky TiAl3 was obtained and its average size was 4.7 μm based on the halide salt route. In the Ti-sponge route, the nucleation of TiAl3 mainly depends on the mutual diffusion of Al and Ti, and TiAlx forms around pure Ti particles, i.e., the so-called Ti–TiAlx mechanism. The average size of the blocky TiAl3 was 9.8 μm based on the Ti–TiAlx mechanism. For the partial Ti-sponge route, the “rich Ti, B area” gradually decreases with the increase in Ti powder’s contents, and large TiAl3 coexists with the small TiAl3. Compared with the Ti-sponge route, the halide salt route can form smaller TiAl3. In the Ti-sponge route, there is a small amount of “rich Ti, B area” due to the influence of the Ti–TiAlx mechanism, which does not meet the requirements of TiB2 growth. In the halide salt route, there is sufficient “rich Ti, B area”, which is conducive to the formation of TiB2. Both the crystal defects and the crowded growth environment caused by the “rich Ti, B area” are fundamental reasons for the fragility and the irregular shape of the TiB2. The refining effect of the Al–Ti–B Master Alloy prepared by the halide salt route is better than the Ti-sponge route. The refining effect of 30% Ti-sponge route is better than that of Ti-sponge route and worse than that of halide salt route.
Superior Radiation Resistance of ZrO2-Modified W Composites
Authors: Cui Bo , Luo Chunyang , Chen Xiaoxi , Zou Chengqin , Li Muhong , Xu Liujie , Yang Jijun , Meng Xianfu , Zhang Haibin , Zhou Xiaosong , Peng Shuming , Shen Huahai
Published: March 2022

The microstructure and mechanical properties of pure W, sintered and swaged W-1.5ZrO2 composites after 1.5 × 1015 Au+/cm2 radiation at room temperature were characterized to investigate the impact of the ZrO2 phase on the irradiation resistance mechanism of tungsten materials. It can be concluded that the ZrO2 phase near the surface consists of two irradiation damage layers, including an amorphous layer and polycrystallization regions after radiation. With the addition of the ZrO2 phase, the total density and average size of dislocation loops, obviously, decrease, attributed to the reason that many more glissile 1/2<111> loops migrate to annihilate preferentially at precipitate interfaces with a higher sink strength of 7.8 × 1014 m−2. The swaged W-1.5ZrO2 alloys have a high enough density of precipitate interfaces and grain boundaries to absorb large numbers of irradiated dislocations. This leads to the smallest irradiation hardening change in hardness of 4.52 Gpa, which is far superior to pure W materials. This work has a collection of experiments and conclusions that are of crucial importance to the materials and nuclear communities.
Synthesis of Activated Carbon from Trachycarpus fortunei Seeds for the Removal of Cationic and Anionic Dyes
Authors: Bakhsh Esraa M. , Bilal Muhammad , Ali Maqsood , Ali Javed , Wahab Abdul , Akhtar Kalsoom , Fagieh Taghreed M. , Danish Ekram Y. , Asiri Abdullah M. , Khan Sher Bahadar
Published: March 2022

The removal of dyes from industrial effluents is one of the most important industrial processes that is currently on academic demand. In this project, for the first time, Trachycarpus fortunei seeds are used as biosources for the synthesis of activated carbon (AC) using physical as well as acid–base chemical methods. The synthesized AC was initially characterized by different instrumental techniques, such as FTIR, BET isotherm, SEM, EDX and XRD. Then, the prepared activated carbon was used as an economical adsorbent for the removal of xylenol orange and thymol blue from an aqueous solution. Furthermore, the effect of different parameters, i.e., concentration of dye, contact time, pH, adsorbent amount, temperature, adsorbent size and agitation speed, were investigated in batch experiments at room temperature. The analysis of different techniques concluded that the pyrolysis method created a significant change in the chemical composition of the prepared AC and the acid-treated AC offered a high carbon/oxygen composite, which is graphitic in nature. The removal of both dyes (xylenol orange and thymol blue) was increased with the increase in the dye’s initial concentration. Isothermal data suggested that the adsorption of both dyes follows the Langmuir model compared to the Freundlich model. The equilibrium time for AC biomass to achieve the removal of xylenol orange and thymol blue dyes was determined to be 60 min, and the kinetic data suggested that the adsorption of both dyes obeyed the pseudo-second order model. The optimal pH for thymol blue adsorption was pH 6, while it was pH 2 for xylenol orange. The adsorption of both dyes increased with the increase in the temperature. The influence of the adsorbent amount indicated that the adsorption capacity (mg/g) of both dyes reduced with the rise in the adsorbent amount. Thus, the current study suggests that AC prepared by an acid treatment from Trachycarpus fortunei seeds is a good, alternative, cost effective, and eco-friendly adsorbent for the effective removal of dyes from polluted water.
Ion Release and Surface Changes of Nickel–Titanium Archwires Induced by Changes in the pH Value of the Saliva—Significance for Human Health Risk Assessment
Authors: Jusufi Osmani Zana , Poljšak Borut , Zelenika Saša , Kamenar Ervin , Marković Kristina , Perčić Marko , Katić Višnja
Published: March 2022

The aim of this study was to explore whether changes in the salivary pH influence mechanical properties, surface roughness, and ion release from NiTi archwires with various surface coatings, and discuss the clinical significance of the findings. The uncoated, rhodium-coated, and nitrified NiTi wires were immersed into artificial saliva of different pH values (4.8, 5.1, 5.5, and 6.6). Released nickel and titanium ions were measured with inductively coupled plasma-optical emission spectroscopy at the end of 28 days. Atomic force microscopy was used to measure the arithmetic average surface roughness Ra, the root-mean-square roughness Rq, and the maximum height of the asperities RZ. The nanoindentation hardness (HIT) and Young’s modulus (EIT) measurements were performed. The change in the pH of artificial saliva is inversely proportional to the release of titanium from both coated and uncoated wires, and the release of nickel from uncoated wires. The surface roughness parameters of both coated and uncoated wires are unaffected by the change in the pH of artificial saliva. The change in the pH of saliva has minor influence on the hardness and Young’s modulus of elasticity of both coated and uncoated wires. The concentration of released metal ions measured was below the recommended upper limit for daily intake; nevertheless, hypersensitivity effects cannot be excluded, even at lower concentrations and at low pH.
Wear Analysis of Additively Manufactured Slipper-Retainer in the Axial Piston Pump
Authors: Klimek Agnieszka , Kluczyński Janusz , Łuszczek Jakub , Bartnicki Adam , Grzelak Krzysztof , Małek Marcin
Published: March 2022

Additive manufacturing (AM) of spare parts is going to become more and more common. In the case of hydraulic solutions, there are also some applications of AM technology related to topological optimization, anti-cavitation improvements, etc. An examination of all available research results shows that authors are using specialized tools and machines to properly prepare AM spare parts. The main aim of this paper is to analyze the influence of quick repair of the damaged slipper-retainer from an axial piston pump by using an AM spare part. Hence, it was prepared with a 100-h test campaign of the AM spare part, which covers the time between damage and supply of the new pump. The material of the slipper-retainer has been identified and replaced by another material—available as a powder for AM, with similar properties as the original. The obtained spare part had been subjected to sandblasting only to simulate extremely rough conditions, directly after the AM process and an analysis of the influence of the high surface roughness of AM part on wear measurements. The whole test campaign has been divided into nine stages. After each stage, microscopic measurements of the pump parts’ surface roughness were made. To determine roughness with proper measurements, a microscopical investigation was conducted. The final results revealed that it is possible to replace parts in hydraulic pumps with the use of AM. The whole test campaign caused a significant increase in the surface roughness of the pump’s original parts, which was worked with the AM spare slipper-retainer: (1) from Ra = 0.54 µm to Ra = 3.84 µm in the case of two tested pistons; (2) from Ra = 0.33 µm to Ra = 1.98 µm in the case of the slipper-retainer. Despite significant increases in the surface roughness of the pump’s parts, the whole test campaign has been successfully finished without any damages to the other important parts of the whole hydraulic test rig.
Concrete by Preplaced Aggregate Method Using Silica Fume and Polypropylene Fibres
Authors: Khanzada Farooq , Nazir Kashif , Ishtiaq Muhammad , Javed Muhammad , Kashif-ur-Rehman Sardar , Aslam Fahid , Musarat Muhammad , Usanova Kseniia
Published: March 2022

Preplaced aggregate concrete (PAC) is prepared in two steps, with the coarse aggregate being initially laid down in the formwork, after which a specialised grout is injected into it. To enhance the properties of concrete and to reduce the emission of CO2 produced during the production of cement, supplementary cementitious materials (SCMs) are used to partially substitute ordinary Portland cement (OPC). In this study, 100 mm × 200 mm (diameter x height) PAC cylinders were cast with 10 per cent of cement being substituted with silica fume; along with that, 1.5% dosage of Macro polypropylene fibres were also introduced into the coarse aggregate matrix. Compressive strength test, splitting tensile strength test, mass loss at 250 °C, and compressive strength at 250 °C were performed on the samples. PAC samples with 10% of cement replaced with Silica Fume (SPAC) were used as control samples. The primary objective of this study was to observe the effect of the addition of Polypropylene fibres to PAC having Silica fume as SCM (FRPAC). The aforementioned tests showed that FRPAC had a lower compressive strength than that of the control mix (SPAC). FRPAC had greater tensile strength than that of NPAC and SPAC. Mass loss at 250 °C was greater in SPAC compared to FRPAC. The compressive strength loss at 250 °C was significantly greater in FRPAC compared to SPAC. FRPAC exhibited a greater strain for the applied stress, and their stress-strain curve showed that FRPAC was more ductile than SPAC.
Precise Modeling of Thermal and Strain Rate Effect on the Hardening Behavior of SiC/Al Composite
Authors: Wang Yanju , Wu Pengfei , He Xiaolei , Zhao Wei , Lan Xiang , Lou Yanshan
Published: March 2022

Temperature and strain rate have significant effects on the mechanical behavior of SiC/Al 2009 composites. This research aimed to precisely model the thermal and strain rate effect on the strain hardening behavior of SiC/Al composite using the artificial neural network (ANN). The mechanical behavior of SiC/Al 2009 composites in the temperature range of 298–623 K under the strain rate of 0.001–0.1 s−1 was investigated by a uniaxial tension experiment. Four conventional models were adopted to characterize the plastic flow behavior in relation to temperature, strain rate, and strain. The ANN model was also applied to characterize the flow behavior of the composite at different strain rates and temperatures. Experimental results showed that the plastic deformation behavior of SiC/Al 2009 composite possesses a coupling effect of strain, strain rate, and temperature. Comparing the prediction error of these models, all four conventional models could not provide satisfactory modeling of flow curves at different strain rates and temperatures. Compared to the four conventional models, the suggested ANN structure dramatically improved the prediction accuracy of the flow curves at different strain rates and temperatures by reducing the prediction error to a maximum of 4.0%. Therefore, the ANN model is recommended for precise modeling of the thermal and strain rate effect on the flow curves of SiC/Al composites.
13C, 27Al and 29Si NMR Investigation of the Hydration Kinetics of Portland-Limestone Cement Pastes Containing CH3-COO−-R+ (R=H or Na) Additives
Authors: Mazur Anton , Tolstoy Peter , Sotiriadis Konstantinos
Published: March 2022

The hydration kinetics of Portland-limestone cement pastes with organic additives in the form of acetic acid and sodium acetate were studied by using solid-state 13C, 27Al and 29Si NMR spectroscopy. The evolution of the relative content of various phases was monitored over the period of one month: amorphous and crystalline calcite (in 13C spectra), ettringite, aluminum in C-S-H gel, calcium aluminates and calcium hydroaluminates (in 27Al spectra), as well as alite, belite and silicon in C-S-H gel (in 29Si spectra). The retarding effect of the additives on cement hydration at early age was demonstrated. We show that the kinetics of phase assemblage formation is influenced by the acetate ion adsorption on the surface of the anhydrous cement components and hydrated phases. The kinetics of formation of ettringite in the cement paste, depending on the addition of acetic and or sodium acetate, is discussed in the context of potential thaumasite sulfate attack.
Antimicrobial TiN-Ag Coatings in Leather Insole for Diabetic Foot
Authors: Marques Sandra M. , Carvalho Isabel , Leite Teófilo R. , Henriques Mariana , Carvalho Sandra
Published: March 2022

This work reports on TiN-Ag antimicrobial coatings deposited by d.c. magnetron sputtering on leather used for insoles on the footwear industry, studies involving the antimicrobial properties of Ag-based functionalized leathers by sputtering techniques are shown. The X-ray diffraction (XRD) results suggested the presence of crystalline fcc-TiN phase for the sample without silver, and also a fcc-Ag phase in the samples containing silver. According to the Scanning Electron Microscopy (SEM) analysis, the coatings were homogeneous and dispersed Ag clusters were detected on the surface of samples with silver content above 8 at. %. The Inductively coupled plasma—optical emission spectrometry (ICP-OES) analysis showed that the ionization of silver over time depends on the morphology of the coatings. The samples did not present cytotoxicity and only samples with incorporated silver presented antibacterial and antifungal activity, highlighting the potential of the TiN-Ag insole coatings for diseases such as diabetic foot.
In Vitro Evaluation of the Antibacterial Activity of EndoSeal MTA, iRoot SP, and AH Plus against Planktonic Bacteria
Authors: Mak Siew Thong , Leong Xin Fang , Tew In Meei , Kumolosasi Endang , Wong Lishen
Published: March 2022

This study aimed to investigate the antibacterial activity of three endodontic sealers, AH Plus, iRoot SP, and EndoSeal MTA, against four planktonic bacteria species. The antibacterial activity of the three endodontic sealers was assessed using a modified direct contact test. Bacteria suspension of Actinomycoses viscosus, Enterococcus faecalis, Staphylococcus aureus, and Streptococcus mutans were left in contact with the sealers that were pre-set or set for 1, 3, 7, and l4 days for an hour. Freshly mixed AH Plus and EndoSeal MTA were highly effective against all four tested bacteria as no surviving bacteria were recovered after treatment. Meanwhile, freshly mixed iRoot SP was not able to kill all bacteria, regardless of the species, demonstrating a weak antibacterial effect. After 24 h, AH Plus lost its antibacterial activity. EndoSeal MTA showed a strong and extended bactericidal effect against S. aureus and S. mutans for 3 days and A. viscosus for 7 days. In conclusion, fresh AH Plus and EndoSeal MTA exhibited a potent effect against all four bacteria species. EndoSeal MTA remained effective after setting when tested against A. viscosus, S. aureus, and S. mutans. Among all tested sealers, iRoot SP demonstrates the weakest antibacterial activity.
Multi-Response Optimization of Al2O3 Nanopowder-Mixed Wire Electrical Discharge Machining Process Parameters of Nitinol Shape Memory Alloy
Authors: Chaudhari Rakesh , Prajapati Parth , Khanna Sakshum , Vora Jay , Patel Vivek K. , Pimenov Danil Yurievich , Giasin Khaled
Published: March 2022

Shape memory alloy (SMA), particularly those having a nickel–titanium combination, can memorize and regain original shape after heating. The superior properties of these alloys, such as better corrosion resistance, inherent shape memory effect, better wear resistance, and adequate superelasticity, as well as biocompatibility, make them a preferable alloy to be used in automotive, aerospace, actuators, robotics, medical, and many other engineering fields. Precise machining of such materials requires inputs of intellectual machining approaches, such as wire electrical discharge machining (WEDM). Machining capabilities of the process can further be enhanced by the addition of Al2O3 nanopowder in the dielectric fluid. Selected input machining process parameters include the following: pulse-on time (Ton), pulse-off time (Toff), and Al2O3 nanopowder concentration. Surface roughness (SR), material removal rate (MRR), and recast layer thickness (RLT) were identified as the response variables. In this study, Taguchi’s three levels L9 approach was used to conduct experimental trials. The analysis of variance (ANOVA) technique was implemented to reaffirm the significance and adequacy of the regression model. Al2O3 nanopowder was found to have the highest contributing effect of 76.13% contribution, Ton was found to be the highest contributing factor for SR and RLT having 91.88% and 88.3% contribution, respectively. Single-objective optimization analysis generated the lowest MRR value of 0.3228 g/min (at Ton of 90 µs, Toff of 5 µs, and powder concentration of 2 g/L), the lowest SR value of 3.13 µm, and the lowest RLT value of 10.24 (both responses at Ton of 30 µs, Toff of 25 µs, and powder concentration of 2 g/L). A specific multi-objective Teaching–Learning-Based Optimization (TLBO) algorithm was implemented to generate optimal points which highlight the non-dominant feasible solutions. The least error between predicted and actual values suggests the effectiveness of both the regression model and the TLBO algorithms. Confirmatory trials have shown an extremely close relation which shows the suitability of both the regression model and the TLBO algorithm for the machining of the nanopowder-mixed WEDM process for Nitinol SMA. A considerable reduction in surface defects owing to the addition of Al2O3 powder was observed in surface morphology analysis.
Structural and Mechanical Changes of AlMgSi0.5 Alloy during Extrusion by ECAP Method
Authors: Harničárová Marta , Valíček Jan , Kušnerová Milena , Kopal Ivan , Lupták Miloslav , Mikuš Rastislav , Pavelek Zdeněk , Fabián Martin , Šepelák Vladimír
Published: March 2022

SPD (several plastic deformations) methods make it possible to obtain an ultrafine-grained structure (UFG) in larger volumes of material and thus improve its mechanical properties. The presented work focuses on the structural and mechanical changes of aluminium alloy AlMgSi0.5 (EN AW 6060) during processing by repeated extrusion through the ECAP rectangular channel. After a four-pass extrusion, the samples’ microstructures were observed using an optical microscope, where refinement of the material grains was confirmed. Tensile tests determined the extrusion forces and allowed interpretation of the changes in the mechanical properties of the stressed alloy. The grain size was refined from 28.90 μm to 4.63 μm. A significant improvement in the strength of the material (by 45%) and a significant deterioration in ductility (to 60%) immediately after the first extrusion was confirmed. The third pass through the die appeared to be optimal for the chosen deformation path, while after the fourth pass, micro-cracks appeared, significantly reducing the strength of the material. Based on the measurement results, new analytical equations were formulated to predict the magnitude or intensity of the volumetric and shape deformations of the structural grain size and, in particular, the adequate increase in the strength and yield point of the material.
Organic Compounds as Corrosion Inhibitors for Carbon Steel in HCl Solution: A Comprehensive Review
Authors: Chen Liangyuan , Lu Dongzhu , Zhang Yanhu
Published: March 2022

Most studies on the corrosion inhibition performance of organic molecules and (nano)materials were conducted within “carbon steel/1.0 M HCl” solution system using similar experimental and theoretical methods. As such, the numerous research findings in this system are sufficient to conduct comparative studies to select the best-suited inhibitor type that generally refers to a type of inhibitor with low concentration/high inhibition efficiency, nontoxic properties, and a simple and cost-economic synthesis process. Before data collection, to help readers have a clear understanding of some crucial elements for the evaluation of corrosion inhibition performance, we introduced the mainstay of corrosion inhibitors studies involved, including the corrosion and inhibition mechanism of carbon steel/HCl solution systems, evaluation methods of corrosion inhibition efficiency, adsorption isotherm models, adsorption thermodynamic parameters QC calculations, MD/MC simulations, and the main characterization techniques used. In the classification and statistical analysis section, organic compounds or (nano)materials as corrosion inhibitors were classified into six types according to their molecular structural characteristics, molecular size, and compound source, including drug molecules, ionic liquids, surfactants, plant extracts, polymers, and polymeric nanoparticles. We outlined the important conclusions obtained from recent literature and listed the evaluation methods, characterization techniques, and contrastable experimental data of these types of inhibitors when used for carbon steel corrosion in 1.0 M HCl solution. Finally, statistical analysis was only performed based on these data from carbon steel/1.0 M HCl solution system, from which some conclusions can contribute to reducing the workload of the acquisition of useful information and provide some reference directions for the development of new corrosion inhibitors.
Current Research and Challenges in Bitumen Emulsion Manufacturing and Its Properties
Authors: Al-Mohammedawi Ahmed , Mollenhauer Konrad
Published: March 2022

The global increase of road infrastructure and its impact on the environment requires serious attention to develop sustainable and environmentally friendly road materials. One group of those materials is produced by using bitumen emulsion. However, there are still scientific and technical obstacles standing against its regular application. The bitumen emulsion formulation process and compositional optimization are subjected to a high number of degrees of freedom. Consequently, obtaining the desired product is mostly based on a series of random and tedious trials because of the enormous number of tests that are carried out to meet the required properties, such as emulsion stability, viscosity, droplet size (and distribution), and bitumen emulsion chemistry. Several pre-established formulation procedures have been presented in the literature. Some of them have technical limitations to be utilized for practical industrial application, whereas others are still not understood enough to be applied in bitumen emulsion formulation. Therefore, discussing some important issues in this field could be useful to offer a practical guide for bitumen emulsion manufacturers when trying to formulate a well-defined bitumen emulsion to best fit its use in pavement infrastructure rather than to simply to meet standard specifications. This review paper aims to enable the ultimate potential of bitumen emulsion by further reviewing the research progress of bitumen emulsion manufacturing and discussing the literature available up to now on this topic, in the realm of bitumen emulsion manufacturing and emulsion chemistry.
Heterogeneous Multitype Fleet Green Vehicle Path Planning of Automated Guided Vehicle with Time Windows in Flexible Manufacturing System
Authors: Gao Jia , Zheng Xiaojun , Gao Feng , Tong Xiaoying , Han Qiaomei
Published: March 2022

In this study, we present and discuss a variant of the classical vehicle routing problem (VRP), namely the heterogeneous multitype fleet green automated guided vehicle (AGV) routing problem with time windows (HFGVRPTW) applied in the workshops of flexible manufacturing systems (FMS). Specifically, based on the analysis of AGV body structure and motion state, transport distance and energy consumption are selected as two optimization objectives. According to the characteristics and application context of the problem, this paper designs a hybrid genetic algorithm with large neighborhood search (GA-LNS) considering the farthest insertion heuristic. GA-LNS is improved by increasing the local search ability of genetic algorithm to enhance the solution optimal quality. Extensive computational experiments which are generated from Solomon’s benchmark instances and a real case of FMS are designed to evaluate and demonstrate the efficiency and effectiveness of the proposed model and algorithm. The experimental results reveal that compared with using the traditional homogeneous fleet, the heterogeneous multitype AGV fleet transportation mode has a huge energy-saving potential in workshop intralogistics.
Analysis of Low-Temperature Magnetotransport Properties of NbN Thin Films Grown by Atomic Layer Deposition
Authors: Vegesna Sahitya V. , Lanka Sai V. , Bürger Danilo , Li Zichao , Linzen Sven , Schmidt Heidemarie
Published: March 2022

Superconducting niobium nitride (NbN) films with nominal thicknesses of 4 nm, 5 nm, 7 nm, and 9 nm were grown on sapphire substrates using atomic layer deposition (ALD). We observed probed Hall resistance (HR) (Rxy) in external out-of-plane magnetic fields up to 6 T and magnetoresistance (MR) (Rxx) in external in-plane and out-of-plane magnetic fields up to 6 T on NbN thin films in Van der Pauw geometry. We also observed that positive MR dominated. Our study focused on the analysis of interaction and localisation effects on electronic disorder in NbN in the normal state in temperatures that ranged from 50 K down to the superconducting transition temperature. By modelling the temperature and magnetic field dependence of the MR data, we extracted the temperature-dependent Coulomb interaction constants, spin–orbit scattering lengths, localisation lengths, and valley degeneracy factors. The MR model allowed us to distinguish between interaction effects (positive MR) and localisation effects (negative MR) for in-plane and out-of-plane magnetic fields. We showed that anisotropic dephasing scattering due to lattice non-idealities in NbN could be neglected in the ALD-grown NbN thin films.
Application of Machine Learning to Study the Association between Environmental Factors and COVID-19 Cases in Mississippi, USA
Authors: Tuluri Francis , Remata Reddy , Walters Wilbur L. , Tchounwou Paul. B.
Published: March 2022

Because of the large-scale impact of COVID-19 on human health, several investigations are being conducted to understand the underlying mechanisms affecting the spread and transmission of the disease. The present study aimed to assess the effects of selected environmental factors such as temperature, humidity, dew point, wind speed, pressure, and precipitation on the daily increase in COVID-19 cases in Mississippi, USA, during the period from January 2020 to August 2021. A machine learning model was used to predict COVID-19 cases and implement preventive measures if necessary. A statistical analysis using Python programming showed that the humidity ranged from 56% to 78%, and COVID-19 cases increased from 634 to 3546. Negative correlations were found between temperature and COVID-19 incidence rate (−0.22) and between humidity and COVID-19 incidence rate (−0.15). The linear regression model showed the model linear coefficients to be 0.92 and −1.29, respectively, with the intercept being 55.64. For the test dataset, the R2 score was 0.053. The statistical analysis and machine learning show that there is no linear dependence of temperature and humidity with the COVID-19 incidence rate.
The Results on Coincidence and Common Fixed Points for a New Type Multivalued Mappings in b-Metric Spaces
Authors: Savanović Nikola , Aranđelović Ivan D. , Mitrović Zoran D.
Published: March 2022

In this paper, we obtain the results of coincidence and common fixed points in b-metric spaces. We work with a new type of multivalued quasi-contractive mapping with nonlinear comparison functions. Our results generalize and improve several recent results. Additionally, we give an application of the obtained results to dynamical systems.
Development of a Methodology for Forecasting the Sustainable Development of Industry in Russia Based on the Tools of Factor and Discriminant Analysis
Authors: Shinkevich Aleksey I. , Akhmetshina Alsu R. , Khalilov Ruslan R.
Published: March 2022

The problem of sustainable development is one of the central issues on the agenda of the global community. However, it is difficult to assess the pace and quality of sustainable development of individual economic systems—in particular, industry—due to the lack of a unified methodological approach. In this regard, the following research goal was formulated—to develop and test a methodology for forecasting sustainable development by using statistical tools. The achievement of the goal was facilitated by the application of formalization methods, factor analysis, discriminant analysis, the method of weighted sum of the criteria, and the method of comparison. The results of the study are new scientific and practical solutions that develop the ability to diagnose economic systems for the transition to environmentally friendly production. Firstly, methodological solutions are proposed to assess the nature of the transition of industry to sustainable development (low, medium, or high rate). The methodology is based on the proposed aggregated indicator of sustainable industrial development based on the results of factor analysis (by the method of principal components). As a result, the patterns of sustainable development of the extractive and manufacturing sectors of the Russian economy are revealed. Secondly, integral indicators of economic, environmental and social factors of sustainable development are calculated, and classification functions for each type of industrial transition to sustainable development (low, medium, or high) are formed through discriminant analysis. Scenarios of industrial development are developed, taking into account the multidirectional trajectories of the socioeconomic development of the country. Thirdly, the DFD model of the process of scenario forecasting of sustainable industrial development is formalized, reflecting the movement of data flows necessary for forecasting sustainable industrial development. It is revealed that the manufacturing industry is expected to maintain a low rate of transition to sustainable development. On the contrary, for the extractive industry, if efforts and resources are concentrated on environmental innovations, average transition rates are predicted. The uniqueness of the proposed approach lies in combining two types of multivariate statistical analysis and taking into account the indicators that characterize the contribution of industrial enterprises to sustainable development.
aSGD: Stochastic Gradient Descent with Adaptive Batch Size for Every Parameter
Authors: Shi Haoze , Yang Naisen , Tang Hong , Yang Xin
Published: March 2022

In recent years, deep neural networks (DNN) have been widely used in many fields. Lots of effort has been put into training due to their numerous parameters in a deep network. Some complex optimizers with many hyperparameters have been utilized to accelerate the process of network training and improve its generalization ability. It often is a trial-and-error process to tune these hyperparameters in a complex optimizer. In this paper, we analyze the different roles of training samples on a parameter update, visually, and find that a training sample contributes differently to the parameter update. Furthermore, we present a variant of the batch stochastic gradient decedent for a neural network using the ReLU as the activation function in the hidden layers, which is called adaptive stochastic gradient descent (aSGD). Different from the existing methods, it calculates the adaptive batch size for each parameter in the model and uses the mean effective gradient as the actual gradient for parameter updates. Experimental results over MNIST show that aSGD can speed up the optimization process of DNN and achieve higher accuracy without extra hyperparameters. Experimental results over synthetic datasets show that it can find redundant nodes effectively, which is helpful for model compression.
Riemann–Hilbert Problems and Soliton Solutions of Type (λ∗, −λ∗) Reduced Nonlocal Integrable mKdV Hierarchies
Authors: Ma Wen-Xiu
Published: March 2022

Reduced nonlocal matrix integrable modified Korteweg–de Vries (mKdV) hierarchies are presented via taking two transpose-type group reductions in the matrix Ablowitz–Kaup–Newell–Segur (AKNS) spectral problems. One reduction is local, which replaces the spectral parameter λ with its complex conjugate λ∗, and the other one is nonlocal, which replaces the spectral parameter λ with its negative complex conjugate −λ∗. Riemann–Hilbert problems and thus inverse scattering transforms are formulated from the reduced matrix spectral problems. In view of the specific distribution of eigenvalues and adjoint eigenvalues, soliton solutions are constructed from the reflectionless Riemann–Hilbert problems.
Some New Post-Quantum Simpson’s Type Inequalities for Coordinated Convex Functions
Authors: Wannalookkhee Fongchan , Nonlaopon Kamsing , Ntouyas Sotiris K. , Sarikaya Mehmet Zeki , Budak Hüseyin
Published: March 2022

In this paper, we establish some new Simpson’s type inequalities for coordinated convex functions by using post-quantum calculus. The results raised in this paper provide significant extensions and generalizations of other related results given in earlier works.
In Vitro and In Vivo Dendritic Cell Immune Stimulation Effect of Low Molecular Weight Fucoidan from New Zealand Undaria pinnatifida
Authors: Liu Litong , Yang Xu , Yuan Pengfei , Cai Shanshan , Bao Jing , Zhao Yanan , Aimaier Alimu , Aipire Adila , Lu Jun , Li Jinyao
Published: March 2022

Low molecular weight fucoidan (LMWF) has been reported to have immunomodulation effects through the increase of the activation and function of macrophages. In this study, the regulating effect of LMWF from Undaria pinnatifida grown in New Zealand on dendritic cells (DCs) was investigated. We discovered that LMWF could stimulate DCs’ maturation and migration, as well as CD4+ and CD8+ T cells’ proliferation in vitro. We proved that this immune promoting activity is activated through TLR4 and its downstream MAPK and NF–κB signaling pathways. Further in vivo (mouse model) investigation showed that LMWF has a strong immunological boosting effect, such as facilitating the proliferation of immune cells and increasing the index of immune organs. These findings suggest that LMWF has a positive immunomodulatory effect and is a promising candidate to supplement cancer immunotherapy.
Inflammation Regulation via an Agonist and Antagonists of α7 Nicotinic Acetylcholine Receptors in RAW264.7 Macrophages
Authors: Tan Yao , Chu Zhaoli , Shan Hongyu , Zhangsun Dongting , Zhu Xiaopeng , Luo Sulan
Published: March 2022

The α7 nicotinic acetylcholine receptor (nAChR) is widely distributed in the central and peripheral nervous systems and is closely related to a variety of nervous system diseases and inflammatory responses. The α7 nAChR subtype plays a vital role in the cholinergic anti-inflammatory pathway. In vivo, ACh released from nerve endings stimulates α7 nAChR on macrophages to regulate the NF-κB and JAK2/STAT3 signaling pathways, thereby inhibiting the production and release of downstream proinflammatory cytokines and chemokines. Despite a considerable level of recent research on α7 nAChR-mediated immune responses, much is still unknown. In this study, we used an agonist (PNU282987) and antagonists (MLA and α-conotoxin [A10L]PnIA) of α7 nAChR as pharmacological tools to identify the molecular mechanism of the α7 nAChR-mediated cholinergic anti-inflammatory pathway in RAW264.7 mouse macrophages. The results of quantitative PCR, ELISAs, and transcriptome analysis were combined to clarify the function of α7 nAChR regulation in the inflammatory response. Our findings indicate that the agonist PNU282987 significantly reduced the expression of the IL-6 gene and protein in inflammatory macrophages to attenuate the inflammatory response, but the antagonists MLA and α-conotoxin [A10L]PnIA had the opposite effects. Neither the agonist nor antagonists of α7 nAChR changed the expression level of the α7 nAChR subunit gene; they only regulated receptor function. This study provides a reference and scientific basis for the discovery of novel α7 nAChR agonists and their anti-inflammatory applications in the future.