bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of Asphalt-Mortar-Aging-Resistance-Modifier Dosage Based on Second-Generation Non-Inferior Sorting Genetic Algorithm
Authors: Lv Yang , Wu Shaopeng , Cui Peide , Amirkhanian Serji , Xu Haiqin , Zou Yingxue , Yang Xinkui
Published: May 2022

The use of steel slag powder instead of filler to prepare asphalt mortar was beneficial to realize the effective utilization of steel slag and improve the performance of asphalt concrete. Nevertheless, the anti-aging properties of steel-slag powder–asphalt mortar need to be further enhanced. This study used antioxidants and UV absorbers in steel-slag powder–asphalt mortar to simultaneously improve its thermal-oxidation and UV-aging properties. The dosage of modifier was optimized by second-generation non-inferior sorting genetic algorithm. Fourier-Transform Infrared Spectroscopy, a dynamic shear rheometer and the heavy-metal-ion-leaching test were used to evaluate the characteristic functional groups, rheological properties and heavy-metal-toxicity characteristics of the steel-slag-powder-modified asphalt mortar, respectively. The results showed that there was a significant correlation between the amount of modifier and G*, δ, and the softening point. When the first peak appeared for G*, δ, and the softening point, the corresponding dosages of x1 were 2.15%, 1.0%, and 1.1%, respectively, while the corresponding dosage of x2 were 0.25%, 0.76%, and 0.38%, respectively. The optimal value of the modifier dosage x1 was 1.2% and x2 was 0.5% after weighing by the NSGA-II algorithm. The asphalt had a certain physical solid-sealing effect on the release of heavy-metal ions in the steel-slag powder. In addition, the asphalt structure was changed under the synergistic effect of oxygen and ultraviolet rays. Therefore, the risk of leaching heavy-metal ions was increased with the inferior asphalt-coating performance on the steel-slag powder.
Machine Learning-Based Surrogate Model for Press Hardening Process of 22MnB5 Sheet Steel Simulation in Industry 4.0
Authors: Abio Albert , Bonada Francesc , Pujante Jaume , Grané Marc , Nievas Nuria , Lange Danillo , Pujol Oriol
Published: May 2022

The digitalization of manufacturing processes offers great potential in quality control, traceability, and the planning and setup of production. In this regard, process simulation is a well-known technology and a key step in the design of manufacturing processes. However, process simulations are computationally and time-expensive, typically beyond the manufacturing-cycle time, severely limiting their usefulness in real-time process control. Machine Learning-based surrogate models can overcome these drawbacks, and offer the possibility to achieve a soft real-time response, which can be potentially developed into full close-loop manufacturing systems, at a computational cost that can be realistically implemented in an industrial setting. This paper explores the novel concept of using a surrogate model to analyze the case of the press hardening of a steel sheet of 22MnB5. This hot sheet metal forming process involves a crucial heat treatment step, directly related to the final part quality. Given its common use in high-responsibility automobile parts, this process is an interesting candidate for digitalization in order to ensure production quality and traceability. A comparison of different data and model training strategies is presented. Finite element simulations for a transient heat transfer analysis are performed with ABAQUS software and they are used for the training data generation to effectively implement a ML-based surrogate model capable of predicting key process outputs for entire batch productions. The resulting final surrogate predicts the behavior and evolution of the most important temperature variables of the process in a wide range of scenarios, with a mean absolute error around 3 °C, but reducing the time four orders of magnitude with respect to the simulations. Moreover, the methodology presented is not only relevant for manufacturing purposes, but can be a technology enabler for advanced systems, such as digital twins and autonomous process control.
A Study of Physicochemical Properties of Stockpile and Ponded Coal Ash
Authors: Šulc Rostislav , Šídlová Martina , Formáček Petr , Snop Roman , Škvára František , Polonská Adéla
Published: May 2022

The article describes chemical and also selected physical properties of ponded high temperature fly ash (FA) and bottom ash (BA) from a Mělník lignite power plant located in the Czech Republic. The research was carried out on samples obtained from drills with a depth of up to 54 m and the age of the samples retrieved from the lowest layers of the stockpile dating back to 1960. At the same time, a comparison was made with fresh fly ash and fresh bottom ash obtained from the identical power plant. The study analyzed a total of 98 stockpile samples. The properties selected were studied across the entire stockpile, namely moisture content, specific density, specific surface, carbon content, elemental and phase composition, pH, electrical conductivity and leachability. SEM analyses were also performed. The performed measurements of chemical properties proved the chemical stability of the material even after several decades of storage in the stockpile. The largest changes are evident in the results of the analyses related to the leachability of SO3, Cl− and F−. In contrast, the pH does not change significantly, and the composition is pH neutral or alkaline. Regarding ponded BA, particle disintegration was noted depending on the increasing core borehole depth.
Algorithmic-Aided Approach for the Design and Evaluation of Curvilinear Steel Bar Structures of Unit Roofs
Authors: Dzwierzynska Jolanta , Lechwar Patrycja
Published: May 2022

Rationalization in structural design in the field of steel structures mostly consists inreducing structural material. The aim of this work was to develop an algorithmic-aided, original and practical approach to shaping curvilinear steel bar structures of modular roofs, enabling their optimization. The first stage of shaping consists in creating algorithms that define the structures of shelters made of four roof units. Algorithmic definitions of the structures made it possible to obtain many variants of the roof structures with the adopted preliminary criteria. In order to evaluate the effectiveness of the individual variants, the genetic optimizations of the structures’ forms were carried out. Assuming that the structures were loaded with self-weights, the cross-sections of the structures’ members were optimized with the permissible deflections, while the structures’ weights were the optimization criteria. This allowed us to eliminate the design variants unfavorable in terms of shape and weight. In contrast, the structures with the most advantageous properties were then optimized for weight under snow and wind loads. The research allowed us to notice how the shapes of the structures influenced their efficiency. The dual approach proposed for shaping, which takes advantage of the generative design and consistent flow of information during shaping, allowed us to achieve better solutions compared to the traditional approach.
Material Optimization Engineering toward xLiFePO4·yLi3V2(PO4)3 Composites in Application-Oriented Li-Ion Batteries
Authors: Pi Yuqiang , Luo Gangwei , Wang Peiyao , Xu Wangwang , Yu Jiage , Zhang Xian , Fu Zhengbing , Yang Xiong , Wang Li , Ding Yu , Wang Feng
Published: May 2022

The development of LiFePO4 (LFP) in high-power energy storage devices is hampered by its slow Li-ion diffusion kinetics. Constructing the composite electrode materials with vanadium substitution is a scientific endeavor to boost LFP’s power capacity. Herein, a series of xLiFePO4·yLi3V2(PO4)3 (xLFP·yLVP) composites were fabricated using a simple spray-drying approach. We propose that 5LFP·LVP is the optimal choice for Li-ion battery promotion, owning to its excellent Li-ion storage capacity (material energy density of 413.6 W·h·kg−1), strong machining capability (compacted density of 1.82 g·cm−3) and lower raw material cost consumption. Furthermore, the 5LFP·LVP||LTO Li-ion pouch cell also presents prominent energy storage capability. After 300 cycles of a constant current test at 400 mA, 75% of the initial capacity (379.1 mA·h) is achieved, with around 100% of Coulombic efficiency. A capacity retention of 60.3% is displayed for the 300th cycle when discharging at 1200 mA, with the capacity fading by 0.15% per cycle. This prototype provides a valid and scientific attempt to accelerate the development of xLFP·yLVP composites in application-oriented Li-ion batteries.
Electrocatalytic Properties of Mixed-Oxide-Containing Composite-Supported Platinum for Polymer Electrolyte Membrane (PEM) Fuel Cells
Authors: Ayyubov Ilgar , Tálas Emília , Salmanzade Khirdakhanim , Kuncser Andrei , Pászti Zoltán , Neațu Ștefan , Mirea Anca G. , Florea Mihaela , Tompos András , Borbáth Irina
Published: May 2022

TiO2-based mixed oxide–carbon composite supports have been suggested to provide enhanced stability for platinum (Pt) electrocatalysts in polymer electrolyte membrane (PEM) fuel cells. The addition of molybdenum (Mo) to the mixed oxide is known to increase the CO tolerance of the electrocatalyst. In this work Pt catalysts, supported on Ti1−xMoxO2–C composites with a 25/75 oxide/carbon mass ratio and prepared from different carbon materials (C: Vulcan XC-72, unmodified and functionalized Black Pearls 2000), were compared in the hydrogen oxidation reaction (HOR) and in the oxygen reduction reaction (ORR) with a commercial Pt/C reference catalyst in order to assess the influence of the support on the electrocatalytic behavior. Our aim was to perform electrochemical studies in preparation for fuel cell tests. The ORR kinetic parameters from the Koutecky–Levich plot suggested a four-electron transfer per oxygen molecule, resulting in H2O. The similarity between the Tafel slopes suggested the same reaction mechanism for electrocatalysts supported by these composites. The HOR activity of the composite-supported electrocatalysts was independent of the type of carbonaceous material. A noticeable difference in the stability of the catalysts appeared only after 5000 polarization cycles; the Black Pearl-containing sample showed the highest stability.
Comprehensive Self-Healing Evaluation of Asphalt Concrete Containing Encapsulated Rejuvenator
Authors: Abadeen Ali Zain Ul , Hussain Arshad , Sathish Kumar Veerappan , Murali Gunasekaran , Vatin Nikolai Ivanovich , Riaz Hassan
Published: May 2022

Ultraviolet radiation, oxidation, temperature, moisture, and traffic loads produce degradation and brittleness in the asphalt pavement. Microcracks develop into macrocracks, which eventually lead to pavement failure. Although asphalt has an inherent capacity for self-healing, it is constricted. As a result, damages build beyond the ability of asphalt to repair themselves. This research employs the in-situ crack healing method of encapsulated rejuvenator technology to enhance the insufficient self-healing capability of roads. This allows the extrinsically induced healing in asphalt to assist it in recovering from damage sustained during service life. Optical microscopy, thermogravimetric analysis, and the compressive load test of capsules were done to characterise their properties. We measured the self-healing behaviour of encapsulated rejuvenator-induced asphalt utilising the three-point bending beam tests on unaged, short-term aged and long-term aged asphalt beams. The rate of oil release before and after healing was quantified using Fourier transform infrared spectroscopy. The results of these tests were utilised to explain the link between healing time, temperature, asphalt ageing, and healing level. Overall, it was determined that the encapsulated rejuvenator was acceptable for mending asphalt mixes because it increased healing temperature and duration, resulting in an up to 80% healing index.
Microstructure Evolution of Al6061 Alloy Made by Additive Friction Stir Deposition
Authors: Zeng Congyuan , Ghadimi Hamed , Ding Huan , Nemati Saber , Garbie Abdelrahman , Raush Jonathan , Guo Shengmin
Published: May 2022

In this paper, the phase structure, composition distribution, grain morphology, and hardness of Al6061 alloy samples made with additive friction stir deposition (AFS-D) were examined. A nearly symmetrical layer-by-layer structure was observed in the cross section (vertical with respect to the fabrication-tool traversing direction) of the as-deposited Al6061 alloy samples made with a back-and-forth AFS-D strategy. Equiaxed grains were observed in the region underneath the fabrication tool, while elongated grains were seen in the “flash region” along the mass flow direction. No clear grain size variance was discovered along the AFS-D build direction except for the last deposited layer. Grains were significantly refined from the feedstock (~163.5 µm) to as-deposited Al6061 alloy parts (~8.5 µm). The hardness of the as-fabricated Al6061 alloy was lower than those of the feedstock and their heat-treated counterparts, which was ascribed to the decreased precipitate content and enlarged precipitate size.
External Sulfate Attack on Cementitious Binders: Limitations and Effects of Sample Geometry on the Quantification of Expansion Stress
Authors: Wagner Matthias , Heisig Anne , Machner Alisa , Beddoe Robin , Heinz Detlef
Published: May 2022

The hollow cylinder method was used to estimate the expansion stress that can occur in concrete due to the crystallisation pressure caused by the formation of ettringite and/or gypsum during external sulphate attack. Hardened cement paste hollow cylinders prepared with Portland cement were mounted in stress cells and exposed to sodium sulphate solutions with two different concentrations (3.0 g L SO42− and 30.0 g L SO42−). Microstructural analysis and finite element modelling was used to evaluate the experimental observations. The expansion stress calculation was verified for a range of diameter/length ratios (0.43–0.60). Thermodynamically predicted maximum expansion stresses are larger than expansion stresses observed in experiments because the latter are affected by the sample geometry, degree of restraint, pore size distribution and relaxation processes. The results indicate that differences in self-constraint at the concave inner and convex outer surfaces of the hollow cylinder lead to an asymmetric expansion stress when ettringite is formed. This leads to macroscopic longitudinal cracks and ultimately failure. Heavy structural components made of concrete are likely to support larger maximum expansion stresses than observed by the hollow cylinder method due to their self-constraint.
Synthesis, Spectroscopic, Structural and Molecular Docking Studies of Some New Nano-Sized Ferrocene-Based Imine Chelates as Antimicrobial and Anticancer Agents
Authors: Khalaf Mai M. , El-Lateef Hany M. Abd , Alhadhrami Abdulrahman , Sayed Fatma N. , Mohamed Gehad G. , Gouda Mohamed , Shaaban Saad , Abu-Dief Ahmed M.
Published: May 2022

The newly synthesized organometallic acetyl ferrocene imine ligand (HL) was obtained by the direct combination of 2-acetyl ferrocene with 2-aminothiophenol. The electronic and molecular structure of acetyl ferrocene imine ligand (HL) was refined theoretically and the chemical quantum factors were computed. Complexes of the acetyl ferrocene imine ligand with metal(II)/(III) ions (Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)) were fabricated. They were inspected by thermal (DTG/TG), spectroscopic techniques (FT-IR, 1H NMR, mass, UV–Vis), molar conductivity, and CHNClM to explicate their structures. Studies using scanning electron microscope (SEM) were conducted on the free acetyl ferrocene imine ligand and its Cd(II) chelate to confirm their nano-structure. To collect an idea about the effect of metal ions on anti-pathogenic properties upon chelation, the newly synthesized acetyl ferrocene imine ligand and some of its metal chelates were tested against a variety of microorganisms, including Bacillus subtilis, Staphylococcus aureus, Salmonella typhimurium, Escherichia coli, Aspergillus fumigatus, and Candida albicans. The ligand and its metal chelate were tested for cytotoxic activity in human cancer (MCF-7 cell viability) and human melanocyte cell line HBF4. It was discovered that the Cd(II) chelate had the lowest IC50 of the three and thus had the prior activity. Molecular docking was utilized to investigate the interaction of acetyl ferrocene imine ligand (HL) with the receptors of the vascular endothelial growth factor receptor VEGFR (PDB ID: 1Y6a), human Topo IIA-bound G-segment DNA crystal structure (PDB ID: 2RGR), and Escherichia coli crystal structure (PDB ID: 3T88).
Friction-Wear Characteristics of Carbon Fiber Reinforced Paper-Based Friction Materials under Different Working Conditions
Authors: Ma Zhiwei , Zheng Changsong , Xiong Cenbo , Yu Liang , Liu Yujian , Zhang Cunzheng
Published: May 2022

To study the friction and wear performance of carbon fiber reinforced friction materials under different working conditions, paper-based friction materials with different fibers were prepared. Experiments on the SAE#2 test bench were conducted to study the infectors including friction torques, surface temperature, coefficient of friction (COF), and surface morphologies. The results were analyzed, which indicated that the carbon fiber reinforced friction material could provide a higher friction torque and a lower temperature rising rate under the applied high pressure and high rotating speed conditions. As the pressure increased from 1 MPa to 2.5 MPa, the friction torque of plant fiber reinforced material increased by 150%, the friction torque of carbon fiber reinforced material increased by 400%, and the maximum temperature of plant fiber reinforced and carbon fiber reinforced material reached the highest value at 1.5 MPa. Thus, carbon fibers not only improved the COF and friction torque performance but also had advantages in avoiding thermal failure. Meanwhile, carbon fiber reinforced friction materials can provide a more stable COF as its variable coefficient (α) only rose from 38.18 to 264.62, from 1 MPa to 2.5 MPa, which was much lower than the natural fiber reinforced friction materials. Simultaneously, due to the good dispersion and excellent mechanical properties of PAN chopped carbon fibers, fewer pores formed on the initial surface, which improved the high wear resistance, especially in the intermedia disc.
Monocular Depth and Velocity Estimation Based on Multi-Cue Fusion
Authors: Qi Chunyang , Zhao Hongxiang , Song Chuanxue , Zhang Naifu , Song Sinxin , Xu Haigang , Xiao Feng
Published: May 2022

Many consumers and scholars currently focus on driving assistance systems (DAS) and intelligent transportation technologies. The distance and speed measurement technology of the vehicle ahead is an important part of the DAS. Existing vehicle distance and speed estimation algorithms based on monocular cameras still have limitations, such as ignoring the relationship between the underlying features of vehicle speed and distance. A multi-cue fusion monocular velocity and ranging framework is proposed to improve the accuracy of monocular ranging and velocity measurement. We use the attention mechanism to fuse different feature information. The training method is used to jointly train the network through the distance velocity regression loss function and the depth loss as an auxiliary loss function. Finally, experimental validation is performed on the Tusimple dataset and the KITTI dataset. On the Tusimple dataset, the average speed mean square error of the proposed method is less than 0.496 m2/s2, and the average mean square error of the distance is 5.695 m2. On the KITTI dataset, the average velocity mean square error of our method is less than 0.40 m2/s2. In addition, we test in different scenarios and confirm the effectiveness of the network.
Research on Electromagnetic Radiation Characteristics of Energetic Materials
Authors: Cui Yuanbo , Kong Deren , Jiang Jian , Gao Shang
Published: May 2022

During the explosion of energetic materials, electromagnetic interference is generated, which can affect the normal operation of surrounding electronic equipment. Therefore, an electromagnetic radiation measurement device based on a short-wave omnidirectional antenna and ultra-wideband omnidirectional antenna was designed to measure the electromagnetic radiation generated by the explosion of energetic materials of different masses, and the electromagnetic radiation characteristics were obtained through data processing. The results showed that the electromagnetic signal can still be collected hundreds of milliseconds after the explosive is detonated, and the electromagnetic radiation generated by the explosion is continuous and intermittent, which is a phenomenon that has not been found in this field at present. The mass of the energetic material had a significant effect on the time-domain characteristics of the electromagnetic radiation generated by the explosion: the higher the mass of the energetic material was, the shorter the delay response of the electromagnetic signal was, the longer the duration was, and the earlier the peak appeared. The frequency of electromagnetic radiation signals generated by the explosion of energetic materials was mainly concentrated below 100 MHz, and the energy was most concentrated in the frequency band of 0~50 MHz. The composition of energetic materials had the greatest influence on the spectral distribution, and the spectral distribution of electromagnetic radiation produced by the explosion of explosives with different compositions had obvious specificity. The electromagnetic radiation intensity generated by the explosion of energetic materials had a strong correlation with the distance from the explosion center, and it significantly decreased as the distance increased. The structure and detonation method of energetic materials changed the geometrical motion pattern during the explosion, resulting in the non-uniformity of electromagnetic radiation propagation.
Convection in a Ferromagnetic Fluid Layer Influenced by Changeable Gravity and Viscosity
Authors: Pant Sumit , Algehyne Ebrahem A.
Published: May 2022

The motive of this work is to numerically evaluate the effect of changeable gravitational fields and varying viscosity on the beginning of convection in ferromagnetic fluid layer. The fluid layer is constrained by two free boundaries and varying gravitational fields that vary with distance across the layer. The authors hypothesized two categories of gravitational field variation, which can be subdivided into six distinct cases: (i) f(z)=z, (ii) f(z)=ez, (iii) f(z)=log(1+z), (iv) f(z)=−z, (v) f(z)=−z2, and (vi) f(z)=z2−2z. The normal mode method was applied, and the single term Galerkin approach was used to solve the ensuing eigenvalue problem. The results imply that, in the first three cases, the gravity variation parameter speeds up the commencement of convection, while, in the last three cases, the viscosity variation parameter and gravity variation parameter slow down the onset of convection. It was also observed that, in the absence of the viscosity variation parameter, the non-buoyancy magnetization parameter destabilizes the impact on the beginning of convection but, in the presence of the viscosity variation parameter, it destabilizes or stabilizes impact on the beginning of convection. In the case of oscillatory convection, the results illustrate that oscillatory modes are not permitted, suggesting the validity of the theory of exchange of stabilities. Additionally, it was also discovered that the system is more stable for case (vi) and more unstable for case (ii).
The Values of Illustration in the Economic Society of Asturias and Its Reflection in Mathematics Education at the Royal Asturian Institute of Nautical Studies and Mineralogy during the Last Quarter of the 18th Century
Authors: López-Esteban Carmen , Almaraz-Menéndez Fernando
Published: May 2022

The Economic Society of Friends of the Country of Asturias, Spain, was an instrument of enlightened reformism which operated in a region with serious economic backwardness. It was born in 1780 at the initiative of Campomanes and responds to the Matritense model, meaning that it focused on economic development and popular education. It is known that Jovellanos directly participated in the establishment of the Royal Institute of Nautical Studies and Mineralogy of Gijón. In this work, the historical method of research in education was used with the objective of determining the sociogenesis of the kind of technical mathematics that was taught in this Institute. The results show the role of the Asturian Economic Society in the creation of the Institute and we also analysed the teaching and curriculum of mathematics that was taught there, and if it was in line with the internal debates of the discipline in that historical moment. The limitations of the Jovellanista model of the Technical Training School for Sailors and Miners created in Gijón are made clear, although the attempt to start it up in such a peripheral place is no less remarkable.
Multiple Roles of Chitosan in Mucosal Drug Delivery: An Updated Review
Authors: Mura Paola , Maestrelli Francesca , Cirri Marzia , Mennini Natascia
Published: May 2022

Chitosan (CS) is a linear polysaccharide obtained by the deacetylation of chitin, which, after cellulose, is the second biopolymer most abundant in nature, being the primary component of the exoskeleton of crustaceans and insects. Since joining the pharmaceutical field, in the early 1990s, CS attracted great interest, which has constantly increased over the years, due to its several beneficial and favorable features, including large availability, biocompatibility, biodegradability, non-toxicity, simplicity of chemical modifications, mucoadhesion and permeation enhancer power, joined to its capability of forming films, hydrogels and micro- and nanoparticles. Moreover, its cationic character, which renders it unique among biodegradable polymers, is responsible for the ability of CS to strongly interact with different types of molecules and for its intrinsic antimicrobial, anti-inflammatory and hemostatic activities. However, its pH-dependent solubility and susceptibility to ions presence may represent serious drawbacks and require suitable strategies to be overcome. Presently, CS and its derivatives are widely investigated for a great variety of pharmaceutical applications, particularly in drug delivery. Among the alternative routes to overcome the problems related to the classic oral drug administration, the mucosal route is becoming the favorite non-invasive delivery pathway. This review aims to provide an updated overview of the applications of CS and its derivatives in novel formulations intended for different methods of mucosal drug delivery.
Psychological Health and Diabetes Self-Management among Patients with Type 2 Diabetes during COVID-19 in the Southwest of Saudi Arabia
Authors: Alkhormi Abdulrhman H. , Mahfouz Mohamed Salih , Alshahrani Najim Z. , Hummadi Abdulrahman , Hakami Wali A. , Alattas Doha H. , Alhafaf Hassan Q. , Kardly Leena E. , Mashhoor Mulook A.
Published: May 2022

Background and objectives: The prevalence of type 2 diabetes in Saudi Arabia is high and rising steeply. However, the management of type 2 diabetic patients has largely employed a medical approach and ignored the self-care management approach. This observation has even been obscured further by the COVID-19 pandemic, which has affected the psychological health of these patients. This study aimed to understand the effects of psychological health and DSM on type 2 diabetic patients in the Jazan region during COVID-19. Materials and methods: An analytical cross-sectional study was employed in this study. Participants were type 2 diabetic patients from the diabetic center at Jazan, Saudi Arabia. The Arabic-translated version of the Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder Scale (GAD-7) were used to collect data. Data were analyzed using SPSS software. Results: Depression and anxiety were higher in females compared to males and were more reported by participants from urban compared to rural settings. Smoking and Khat chewing were inappropriate diabetic self-care management practices while exercising was appropriate. A negative correlation was observed between depression vs. health care utilization, and depression vs. diabetic self-care management. Anxiety results also showed similar findings to that of depression. Additionally, depression and anxiety were easily predicted by urban residence, and diabetic self-care management was predicted by exercise. Conclusions: Adequate self-care behavior in patients with type 2 diabetes is needed. Medical professionals should ensure improved efforts to accurately ascertain how an individual can implement the recommended lifestyle changes and facilitate self-care education.
Infrared Spectroscopic Study of Multi-Component Lipid Systems: A Closer Approximation to Biological Membrane Fluidity
Authors: Klaiss-Luna Maria C. , Manrique-Moreno Marcela
Published: May 2022

Membranes are essential to cellular organisms, and play several roles in cellular protection as well as in the control and transport of nutrients. One of the most critical membrane properties is fluidity, which has been extensively studied, using mainly single component systems. In this study, we used Fourier transform infrared spectroscopy to evaluate the thermal behavior of multi-component supported lipid bilayers that mimic the membrane composition of tumoral and non-tumoral cell membranes, as well as microorganisms such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus. The results showed that, for tumoral and non-tumoral membrane models, the presence of cholesterol induced a loss of cooperativity of the transition. However, in the absence of cholesterol, the transitions of the multi-component lipid systems had sigmoidal curves where the gel and fluid phases are evident and where main transition temperatures were possible to determine. Additionally, the possibility of designing multi-component lipid systems showed the potential to obtain several microorganism models, including changes in the cardiolipin content associated with the resistance mechanism in Staphylococcus aureus. Finally, the potential use of multi-component lipid systems in the determination of the conformational change of the antimicrobial peptide LL-37 was studied. The results showed that LL-37 underwent a conformational change when interacting with Staphylococcus aureus models, instead of with the erythrocyte membrane model. The results showed the versatile applications of multi-component lipid systems studied by Fourier transform infrared spectroscopy.
Application of Clove Oil and Sonication Process on the Influence of the Functional Properties of Mung Bean Flour-Based Edible Film
Authors: Keawpeng Ittiporn , Lekjing Somwang , Paulraj Balaji , Venkatachalam Karthikeyan
Published: May 2022

The present study was aimed to investigate the effects of sonication and clove oil incorporation on the improvement of physical, antioxidant, and antimicrobial properties and lipid oxidation inhibiting abilities of mung bean flour (MF)-based films. There were three groups of films tested (1) MF: mung bean flour alone, (2) MFC: MF incorporated with 2% clove oil (C), and (3) MFCU: MFC prepared with sonication (25 kHz, 100% amplitude, 10 min). Film thickness and bulk density showed slight differences, and moisture content, solubility, and water vapor permeability significantly differed between the formulations. Tensile strength, elongation at break, and Young’s modulus were highest for the MFCU films, followed by MFC and MF in rank order. Furthermore, the Fourier-transform infrared spectroscopy results also demonstrated that the clove oil and sonication treatment had improved the interconnections of the biopolymers, thus increasing the physical strength of the film. Phytochemicals in terms of total phenolics and total flavonoids were elevated in the MFCU films and contributed to stronger radical scavenging abilities (p < 0.05). MFC and MFCU films showed a strong antibacterial control of the Gram-positive Staphylococcus aureus (S. aureus) and also of the Gram-negative Campylobacter jejuni (C. jejuni). Overall, the lipid oxidation indicators Thiobarbituric acid reactive substances (TBARS, peroxide value, p-anisidine value, and totox value) showed significantly high inhibition, attributed to radical scavenging activities in the MFCU and MFC samples. The mung bean flour films incorporated with clove oil and prepared with sonication have good potential as packaging materials for food due to strong physical, antimicrobial, and antioxidant properties, as well as lipid oxidation inhibiting abilities.
Investigation on the Effect of Annealing Temperature on the Side Ohmic Contact Characteristics for Double Channel GaN/AlGaN Epitaxial Layer
Authors: Meng Qingzhi , Lin Qijing , Jing Weixuan , Zhao Na , Yang Ping , Lu Dejiang
Published: May 2022

A side ohmic contact mode for the double channel GaN/AlGaN epitaxial layer is proposed in this paper. Rectangle transmission line model (TLM) electrodes are prepared, and the specific contact resistance is tested at the annealing temperatures from 700 °C to 850 °C. The results show that the minimum specific contact resistance is 2.58 × 10−7 Ω·cm2 at the annealing temperature of 750 °C, which is three to four times lower than the surface contact mode. Scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and atomic force microscope (AFM) were carried out for the analysis of the morphology, element composition, and the height fluctuation at the contact edge. With the increase in the annealing temperature, the specific contact resistance decreases due to the alloying of electrodes and the raised number of N vacancies. However, when the annealing temperature exceeds 800 °C, the state of the stress in the electrode films transforms from compressive stress to tensile stress. Besides, the volume expansion of metal electrode film and the increase in the roughness at the contact edge leads to the degradation of the side ohmic contact characteristics.
Microfluidics Temperature Compensating and Monitoring Based on Liquid Metal Heat Transfer
Authors: Meng Jiyu , Yu Chengzhuang , Li Shanshan , Wei Chunyang , Dai Shijie , Li Hui , Li Junwei
Published: May 2022

Microfluidic devices offer excellent heat transfer, enabling the biochemical reactions to be more efficient. However, the precision of temperature sensing and control of microfluids is limited by the size effect. Here in this work, the relationship between the microfluids and the glass substrate of a typical microfluidic device is investigated. With an intelligent structure design and liquid metal, we demonstrated that a millimeter-scale industrial temperature sensor could be utilized for temperature sensing of micro-scale fluids. We proposed a heat transfer model based on this design, where the local correlations between the macro-scale temperature sensor and the micro-scale fluids were investigated. As a demonstration, a set of temperature-sensitive nucleic acid amplification tests were taken to show the precision of temperature control for micro-scale reagents. Comparations of theoretical and experimental data further verify the effectiveness of our heat transfer model. With the presented compensation approach, the slight fluorescent intensity changes caused by isothermal amplification polymerase chain reaction (PCR) temperature could be distinguished. For instance, the probability distribution plots of fluorescent intensity are significant from each other, even if the amplification temperature has a difference of 1 °C. Thus, this method may serve as a universal approach for micro–macro interface sensing and is helpful beyond microfluidic applications.
Single-Pixel Near-Infrared 3D Image Reconstruction in Outdoor Conditions
Authors: Osorio Quero C. , Durini D. , Rangel-Magdaleno J. , Martinez-Carranza J. , Ramos-Garcia R.
Published: May 2022

In the last decade, the vision systems have improved their capabilities to capture 3D images in bad weather scenarios. Currently, there exist several techniques for image acquisition in foggy or rainy scenarios that use infrared (IR) sensors. Due to the reduced light scattering at the IR spectra it is possible to discriminate the objects in a scene compared with the images obtained in the visible spectrum. Therefore, in this work, we proposed 3D image generation in foggy conditions using the single-pixel imaging (SPI) active illumination approach in combination with the Time-of-Flight technique (ToF) at 1550 nm wavelength. For the generation of 3D images, we make use of space-filling projection with compressed sensing (CS-SRCNN) and depth information based on ToF. To evaluate the performance, the vision system included a designed test chamber to simulate different fog and background illumination environments and calculate the parameters related to image quality.
THz Multi-Mode Q-Plate with a Fixed Rate of Change of the Optical Axis Using Form Birefringence
Authors: Koral Can , Mazaheri Zahra , Andreone Antonello
Published: May 2022

We report the design, fabrication and experimental validation of a THz all-dielectric multi-mode q-plate having a fixed rate of change of the optical axis. The device consists of space-variant birefringent slabs manufactured by 3D printing using melt-extruded Acrylonitrile Butadiene Styrene (ABS). The desired form birefringence is analytically evaluated and experimentally measured by the THz time domain spectroscopy technique. The manufactured q-plate design is characterized using a polarization-sensitive imaging setup. The full electric field spatial maps are acquired from the beam propagating through the q-plate. The device enables the realization of both radial and azimuthal vector beams at discrete frequency intervals by controlling the space-dependent orientation of the ordinary and extraordinary axes in the transverse plane with a multi-mode sequence.
High-Efficiency Flicker-Free LED Driver with Soft-Switching Feature
Authors: Cheng Hung-Liang , Hwang Lain-Chyr , Chang Heidi , Wang Qi-You , Cheng Chun-An
Published: May 2022

A novel interleaved DC-DC buck converter is proposed to drive high-brightness light-emitting diodes (LEDs). The circuit configuration mainly consists of two buck converters, which are connected in parallel and use interleaved operation. Through interleaved operation, the power capability of the converter is doubled. Traditionally, two individual inductors are used in the two buck converters. The difference between conventional parallel-operated buck converters using two energy storage inductors and the proposed circuit is that the proposed circuit uses two small inductors and a coupled inductor that replace the two inductors of the buck converters. In this way, both buck converters can be designed to operate in discontinuous-current mode (DCM), even if the magnetizing inductance of the coupled inductor is large. Therefore, the freewheeling diodes can achieve zero-current switching off (ZCS). Applying the principle of conservation of magnetic flux, the magnetizing current is converted between the two windings of the coupled inductor. Because nearly constant magnetizing current continuously flows into the output, the output voltage ripple can be effectively reduced without the use of large-value electrolytic capacitors. In addition, each winding current can drop from positive to negative, and this reverse current can discharge the parasitic capacitor of the active switch to zero volts. In this way, the active switches can operate at zero-voltage switching on (ZVS), leading to low switching losses. A 180 W prototype LED driver was built and tested. Our experimental results show satisfactory performance.
Stop-Flow Lithography for the Continuous Production of Degradable Hydrogel Achiral Crescent Microswimmers
Authors: Xiong Junfeng , Song Xiaoxia , Cai Yuhang , Liu Jiahe , Li Yangyuan , Ji Yaqiang , Guo Liang , Cheang U Kei
Published: May 2022

The small size of robotic microswimmers makes them suitable for performing biomedical tasks in tiny, enclosed spaces. Considering the effects of potentially long-term retention of microswimmers in biological tissues and the environment, the degradability of microswimmers has become one of the pressing issues in this field. While degradable hydrogel was successfully used to prepare microswimmers in previous reports, most hydrogel microswimmers could only be fabricated using two-photon polymerization (TPP) due to their 3D structures, resulting in costly robotic microswimmers solution. This limits the potential of hydrogel microswimmers to be used in applications where a large number of microswimmers are needed. Here, we proposed a new type of preparation method for degradable hydrogel achiral crescent microswimmers using a custom-built stop-flow lithography (SFL) setup. The degradability of the hydrogel crescent microswimmers was quantitatively analyzed, and the degradation rate in sodium hydroxide solution (NaOH) of different concentrations was investigated. Cytotoxicity assays showed the hydrogel crescent microswimmers had good biocompatibility. The hydrogel crescent microswimmers were magnetically actuated using a 3D Helmholtz coil system and were able to obtain a swimming efficiency on par with previously reported microswimmers. The results herein demonstrated the potential for the degradable hydrogel achiral microswimmers to become a candidate for microscale applications.
Wireless Micro Soft Actuator without Payloads Using 3D Helical Coils
Authors: Lee Seonghyeon , Jung Woojun , Ko Kyungho , Hwang Yongha
Published: May 2022

To receive a greater power and to demonstrate the soft bellows-shaped actuator’s wireless actuation, micro inductors were built for wireless power transfer and realized in a three-dimensional helical structure, which have previously been built in two-dimensional spiral structures. Although the three-dimensional helical inductor has the advantage of acquiring more magnetic flux linkage than the two-dimensional spiral inductor, the existing microfabrication technique produces a device on a two-dimensional plane, as it has a limit to building a complete three-dimensional structure. In this study, by using a three-dimensional printed soluble mold technique, a three-dimensional heater with helical coils, which have a larger heating area than a two-dimensional heater, was fabricated with three-dimensional receiving inductors for enhanced wireless power transfer. The three-dimensional heater connected to the three-dimensional helical inductor increased the temperature of the liquid and gas inside the bellows-shaped actuator while reaching 176.1% higher temperature than the heater connected to the two-dimensional spiral inductor. Thereby it enables a stroke of the actuator up to 522% longer than when it is connected to the spiral inductor. Therefore, three-dimensional micro coils can offer a significant approach to the development of wireless micro soft robots without incurring heavy and bulky parts such as batteries.
Single Cell Isolation Using Optical Tweezers
Authors: Keloth Anusha , Anderson Owen , Risbridger Donald , Paterson Lynn
Published: May 2022

Optical tweezers offer a non-contact method for selecting single cells and translocating them from one microenvironment to another. We have characterized the optical tweezing of yeast S. cerevisiae and can manipulate single cells at 0.41 ± 0.06 mm/s using a 26.8 ± 0.1 mW from a 785 nm diode laser. We have fabricated and tested three cell isolation devices; a micropipette, a PDMS chip and a laser machined fused silica chip and we have isolated yeast, single bacteria and cyanobacteria cells. The most effective isolation was achieved in PDMS chips, where single yeast cells were grown and observed for 18 h without contamination. The duration of budding in S. cerevisiae was not affected by the laser parameters used, but the time from tweezing until the first budding event began increased with increasing laser energy (laser power × time). Yeast cells tweezed using 25.0 ± 0.1 mW for 1 min were viable after isolation. We have constructed a micro-consortium of yeast cells, and a co-culture of yeast and bacteria, using optical tweezers in combination with the PDMS network of channels and isolation chambers, which may impact on both industrial biotechnology and understanding pathogen dynamics.
Distinguishing Allies from Enemies—A Way for a New Green Revolution
Authors: Lino-Neto Teresa , Baptista Paula
Published: May 2022

Plants are continually interacting in different ways and levels with microbes, resulting in direct or indirect effects on plant development and fitness. Many plant–microbe interactions are beneficial and promote plant growth and development, while others have harmful effects and cause plant diseases. Given the permanent and simultaneous contact with beneficial and harmful microbes, plants should avoid being infected by pathogens while promoting mutualistic relationships. The way plants perceive multiple microbes and trigger plant responses suggests a common origin of both types of interaction. Despite the recent advances in this topic, the exploitation of mutualistic relations has still not been fully achieved. The holistic view of different agroecosystem factors, including biotic and abiotic aspects, as well as agricultural practices, must also be considered. This approach could pave the way for a new green revolution that will allow providing food to a growing human population in the context of threat such as that resulting from climate change.
Influence of Metal Concentration and Plumbing Materials on Legionella Contamination
Authors: Rakić Anita , Vukić Lušić Darija , Jurčev Savičević Anamarija
Published: May 2022

Legionella colonization of water supply pipes is a significant public health problem. The objective of this work was to evaluate Legionella colonization in hotel hot water systems and to investigate the relationship between metal concentrations, piping materials (galvanized iron pipes and plastic pipes), and Legionella proliferation. Concentrations of calcium and magnesium ions and the presence of Legionella pneumophila were determined in a total of 108 water samples from the hot water systems of four hotels in Split-Dalmatia County over a 12-month period, and additional data on piping materials were collected. L. pneumophila was isolated in 23.1% of all samples—in 28.8% (15/52) of water samples from galvanized iron pipes and in 17.8% (10/56) of samples from plastic pipes. L. pneumophila serogroups 2–14 were isolated from all samples. This study found higher prevalence of L. pneumophila at higher concentrations of Ca and Mg ions (except for Mg and plastic pipes). The metal parts of the water supply may be important factors in Legionella contamination due to the possibility of lime scale or roughness of the pipes. Higher Ca and Mg ion concentrations increased the risk of Legionella colonization.