bluuebunny/crossref_metadata_2025 huggingface dataset:
Ferroelectric, Dielectric and Electromechanical Performance of Ba0.92Ca0.08Ti0.95Zr0.05O3 Ceramics with an Enhanced Curie Temperature
Authors: Hernández-Moreno Ana Cristina , Reyes-Montero Armando , Carreño-Jiménez Brenda , Acuautla Mónica , Pardo Lorena
Published: March 2023

Ba0.92Ca0.08Ti0.95Zr0.05O3 (BCZT8-5) ceramic materials have been scarcely studied as lead-free piezo/ferroelectrics despite their enhanced Curie temperature (>100 °C) with respect to most studied BCZT compositions. In this work, homogeneous dense BCZT8-5 ceramics with grain size in the range of 20 μm, and optimum ferroelectric, dielectric, and electromechanical performance, were prepared by the mixed oxides route using moderate synthesis (1250 °C-2 h) and sintering (1400 °C-2 h) conditions. Thickness-poled thin disks and monomodal shear plate resonators were used for the determination of piezoelectric coefficients, coupling factors, elastic, and dielectric permittivity coefficients, including all losses, by iterative analysis of impedance curves at resonance. Furthermore, the thermal evolution of the piezoelectric characteristics at resonance was determined to assess the enhanced working range of the ceramics (≈100 °C). Ferroelectric hysteresis loops and strains vs. electric-field butterfly loops were also measured and showed soft behavior with Ec = 2 kV/cm, Pr = 12 μC/cm2 after a maximum applied field of 3 kV was used. The ceramics showed a high endurance of P-E cycles to electrical fatigue up to 107 cycles. Moreover, dielectric properties as a function of temperature were also accomplished and showed nearly normal ferroelectric behavior, characteristic of samples with low crystallographic disorder. Overall, these ceramics showed high sensitivity and higher stability than other currently studied BCZT compositions.
Preparation and Application of a NaCl-KCl-CsCl-Cs2ZrCl6 Composite Electrolyte
Authors: Zou Wenzhen , Wu Yanke , Wang Lijun , Yan Guoqing , Ma Zhaohui , Zhang Jiandong
Published: March 2023

Using ternary molten salt with a molar ratio of NaCl:KCl:CsCl = 30:24.5:45.5 and ZrCl4 as raw materials to prepare a NaCl-KCl-CsCl-Cs2ZrCl6 composite electrolyte. Characterizing by XRD, ICP-AES, optical microscopy and SEM-EDS, the results showed that when the molar ratio of CsCl:ZrCl4 ≥ 2:1, Cs2ZrCl6 was generated according to the stoichiometric reaction; when the molar ratio of CsCl:ZrCl4 < 2:1, CsCl in molten salt was almost completely converted to Cs2ZrCl6, and there was a ZrCl4 phase. When the molar ratio of CsCl:ZrCl4 = 2:1, with the increase of the reaction temperature and reaction time, the concentration of zirconium ions first increased and then decreased. The optimized preparation process conditions are: the 2:1 molar ratio of CsCl to ZrCl4 in NaCl-KCl-CsCl, 500 °C of reaction temperature of and 3 h of reaction time. Under this condition, 99.68% conversion rate from ZrCl4 to Cs2ZrCl6 was obtained. Taking the prepared NaCl-KCl-CsCl-Cs2ZrCl6 composite electrolyte as a raw material, a preliminary study of molten salt electrolytic refining zirconium was carried out, and a refined zirconium product with a dendrite of 10.61 mm was obtained under the conditions of a zirconium ions concentration of 5%, an electrolysis temperature of 750 °C, a current density of 0.1 A/cm2, and an electrolysis time of 9 h, indicating that the composite electrolyte can be used for the electrolytic refining of zirconium.
A Novel Feedforward Model of Piezoelectric Actuator for Precision Rapid Cutting
Authors: Zhong Bowen , Liu Shilin , Wang Chenjun , Jin Ziqi , Sun Lining
Published: March 2023

The piezoelectric actuator has been widely used in modern precision cutting technology due to its fast response speed and high positioning accuracy. In recent years, with the development of precision technology, modern cutting requires higher and higher cutting accuracy and efficiency. Therefore, this paper proposes a feedforward control method based on the modified Bouc–Wen (MBW) model. Firstly, a novel asymmetrical modified Bouc–Wen model with an innovative form of shape control function is developed to model the hysteresis nonlinearity property of piezoelectric actuators. Then, a self-adaptive cooperative particle swarm optimization (PSO) algorithm is developed to identify the parameters of MBW model. The comparative evaluation reveals that the MBW model outperforms the classical Bouc–Wen (CBW) model by 66.4% in modeling accuracy. Compared with traditional PSO algorithm, the self-adaptive cooperative PSO algorithm can obtain minimum fitness in parameter identification. Furthermore, the feedforward control strategy is realized to improve the position tracking accuracy. A position tracking experiment verifies that the feedforward control strategy improves the tracking accuracy of piezoelectric actuators significantly compared with the open-loop control strategy.
Modeling of Rapid Response Characteristics of Piezoelectric Actuators for Ultra-Precision Machining
Authors: Zhong Bowen , Liao Zhan , Zhang Xi , Jin Ziqi , Sun Lining
Published: March 2023

Piezoelectric actuators are characterized by high positioning accuracy, high stiffness and a fast response and are widely used in ultra-precision machining technologies such as fast tool servo technology and ultrasonic machining. The rapid response characteristics of piezoelectric actuators often determine the overall quality of machining. However, there has been little research on the fast response characteristics of piezoelectric actuators, and this knowledge gap will lead to low precision and poor quality of the final machining. The fast response characteristics of a piezoelectric actuator were studied in this work. Firstly, the piezoelectric actuator was divided into a no-load state and a load state according to the working state. A fast response analysis and output characteristic analysis were carried out, the corresponding dynamic model was established, and then the model was simulated. Finally, an experimental system was established to verify the dynamic model of the piezoelectric actuator’s fast response by conducting an experiment in which the piezoelectric actuator bounces a steel ball. The experimental results verify the correctness of the model and show that the greater the cross-sectional area and height of the piezoelectric actuator, the higher the bouncing height of the ball, and the better the dynamic performance of the piezoelectric actuator. It is believed that this study has guiding significance for the application of the dynamic characteristics of piezoelectric actuators in the machining field.
Vibration Analysis of Locally Resonant Beams with L-Joint Using an Exact Wave-Based Vibration Approach
Authors: Lv Hangyuan , Zhang Rong , Chen Changji , Ma Hui , Huang Xianzhen , Yu Zhongliang
Published: March 2023

This paper employed and developed the wave-based vibration approach to analyze the band-gap characteristics of a locally resonant (LR) beam with L-joint, which is common in engineering practices. Based on the proposed modular approach, where the discontinuities on the beam are created as modules, the design and modeling work for such an LR beam can be simplified considerably. Then, three kinds of LR beams with an L-joint suspended with transverse-force type resonators and two cells of longitudinal-force-moment type resonators are analyzed, respectively, to show their suppression ability on the axial wave’s propagation and widened effect on the low-frequency band-gaps, where the longitudinal-force-moment type resonators at the 3rd–4th cells can better suppress the propagation of the axial waves. Meanwhile, the proposed analysis results are compared with the ones obtained with the finite element method and further verified the accuracy and efficiency of the wave-based vibration approach. The aim of this paper is to provide an efficient method for the analysis and design of the LR beam with L-joint for low-frequency vibration attenuation in engineering practices.
Charge Trapping and Emission Properties in CAAC-IGZO Transistor: A First-Principles Calculations
Authors: Wang Ziqi , Lu Nianduan , Wang Jiawei , Geng Di , Wang Lingfei , Yang Guanhua
Published: March 2023

The c-axis aligned crystalline indium-gallium-zinc-oxide field-effect transistor (CAAC-IGZO FET), exhibiting an extremely low off-state leakage current (~10−22 A/μm), has promised to be an ideal candidate for Dynamic Random Access Memory (DRAM) applications. However, the instabilities leaded by the drift of the threshold voltage in various stress seriously affect the device application. To better develop high performance CAAC-IGZO FET for DRAM applications, it’s essential to uncover the deep physical process of charge transport mechanism in CAAC-IGZO FET. In this work, by combining the first-principles calculations and nonradiative multiphonon theory, the charge trapping and emission properties in CAAC-IGZO FET have been systematically investigated. It is found that under positive bias stress, hydrogen interstitial in Al2O3 gate dielectric is probable effective electron trap center, which has the transition level (ε (+1/−1) = 0.52 eV) above Fermi level. But it has a high capture barrier about 1.4 eV and low capture rate. Under negative bias stress, oxygen vacancy in Al2O3 gate dielectric and CAAC-IGZO active layer are probable effective electron emission centers whose transition level ε (+2/0) distributed at −0.73~−0.98 eV and 0.69 eV below Fermi level. They have a relatively low emission barrier of about 0.5 eV and 0.25 eV and high emission rate. To overcome the instability in CAAC-IGZO FET, some approaches can be taken to control the hydrogen concentration in Al2O3 dielectric layer and the concentration of the oxygen vacancy. This work can help to understand the mechanisms of instability of CAAC-IGZO transistor caused by the charge capture/emission process.
Effect of Gate Bias Stress on the Electrical Characteristics of Ferroelectric Oxide Thin-Film Transistors with Poly(Vinylidenefluoride-Trifluoroethylene)
Authors: Gu Bon-Seong , Park Eun-Seo , Kwon Jin-Hyuk , Kim Min-Hoi
Published: March 2023

We investigated the effect of gate bias stress (GBS) on the electrical characteristics of ferroelectric oxide thin-film transistors (FeOxTFTs) with poly(vinylidenefluoride-trifluoroethylene). Generally, conventional oxide thin-film transistors (OxTFTs) with dielectric gate insulators exhibit a small negative shift under negative gate bias stress (NBS) and a large positive shift under positive gate bias stress (PBS) in transfer characteristic curves. In contrast, the FeOxTFTs show a small positive shift and a large negative shift under NBS and PBS, respectively. It was confirmed that sufficient changes in the electrical characteristics are obtained by 10 min NBS and PBS. The changed electrical characteristics such as threshold voltage shift, memory on- and memory off-current were maintained for more than 168 h after NBS and 24 h after PBS. It is deduced that, since the dipole alignment of the ferroelectric layer is maximized during GBS, these changes in electrical properties are caused by the remnant dipole moments still being retained during the gate sweep. The memory on- and memory off-current are controlled by GBS and the best on/off current ratio at 107 was obtained after NBS. By repeatedly alternating NBS and PBS, the electrical characteristics were reversibly changed. Our results provide the scientific and technological basis for the development of stability and performance optimization of FeOxTFTs.
Influences of Flood Conditions on Dynamic Characteristics of Novel 3D-Printed Porous Bridge Bearings
Authors: Sengsri Pasakorn , Kaewunruen Sakdirat
Published: March 2023

As the key safety-critical component of a bridge support system, bridge bearings are extensively used to accommodate, balance, and transfer differential displacements and loads between the superstructure and substructure of a bridge during operations. Several studies have been conducted to obtain dynamic modal parameters of traditional bridge bearings only in perfectly dry environments. However, in extreme weather conditions (e.g., heavy rain, flash floods, etc.), water can ingress and change the bearings’ properties. In this study, novel 3D-printed porous bridge bearings (3DPPBBs) have been fabricated by Fused Deposition Modeling (FDM) with thermoplastic polyurethane (TPU) filaments. This study is the first to determine the influences of flood conditions on their dynamic properties, which has never been done before. An idealised single degree of freedom (ISDOF) for these novel bearings is considered for the non-destructive field-testing technique of the critical bridge component. A series of experimental tests have been performed under several conditions of flooding levels. The new results unprecedentedly indicate that relatively higher dynamic damping ratios can be found with the increasing flood levels. In contrast, the natural frequencies and dynamic stiffness decrease with the same conditions. Novel insights are essential for bridge engineers to assess and monitor bridge vibrations exposed to extreme weather conditions.
Structural, Optical, Magnetic and Electrochemical Properties of CeXO2 (X: Fe, and Mn) Nanoparticles
Authors: Kumar Shalendra , Ahmed Faheem , Shaalan Nagih M. , Arshi Nishat , Dalela Saurabh , Chae Keun H.
Published: March 2023

CeXO2 (X: Fe, Mn) nanoparticles, synthesized using the coprecipitation route, were investigated for their structural, morphological, magnetic, and electrochemical properties using X-ray diffraction (XRD), field emission transmission electron microscopy (FE-TEM), dc magnetization, and cyclic voltammetry methods. The single-phase formation of CeO2 nanoparticles with FCC fluorite structure was confirmed by the Rietveld refinement, indicating the successful incorporation of Fe and Mn in the CeO2 matrix with the reduced dimensions and band gap values. The Raman analysis supported the lowest band gap of Fe-doped CeO2 on account of oxygen non-stoichiometry. The samples exhibited weak room temperature ferromagnetism, which was found to be enhanced in the Fe doped CeO2. The NEXAFS analysis supported the results by revealing the oxidation state of Fe to be Fe2+/Fe3+ in Fe-doped CeO2 nanoparticles. Further, the room temperature electrochemical performance of CeXO2 (X: Fe, Mn) nanoparticles was measured with a scan rate of 10 mV s−1 using 1 M KCL electrolyte, which showed that the Ce0.95Fe0.05O2 electrode revealed excellent performance with a specific capacitance of 945 Fּ·g−1 for the application in energy storage devices.
Spherical Attapulgite/Silica Aerogels Fabricated via Different Drying Methods with Excellent Adsorption Performance
Authors: Zhu Zhixiang , Wang Shengyuan , Zhong Ya , You Qi , Gao Jun , Cui Sheng , Shen Xiaodong
Published: March 2023

Dye wastewater has caused great harm to the environment, which is an urgent problem to be solved. As typical three-dimensional porous materials, aerogels have attracted great interest in dye wastewater treatment. In this work, spherical attapulgite/silica (ATP/SiO2) gels were initially prepared by easily scalable sol-gel dripping methods and then dried to aerogels with three drying techniques, namely, supercritical CO2 drying (SCD), freeze-drying (FD), and ambient pressure drying (APD). The effect of the drying techniques and heat-treated temperature on the physical characteristic, morphological properties, microstructure, and chemical structure of the spherical ATP/SiO2 aerogels were investigated. The macroscopic morphology of the spherical ATP/SiO2 aerogels was homogeneous and integrated without local cracking. The average pore diameter and specific surface area of the spherical ATP/SiO2 aerogels prepared by the three drying techniques were in the range of 6.8–8.6 nm and 218.5–267.4 m2/g, respectively. The heat treatment temperature had a significant effect on the pore structure and the wetting properties of the aerogels. The 600 °C heat-treated aerogels were subjected to adsorption tests in methylene blue (MB) solution (60 mg/g, 100 mL), which exhibited a great adsorption capacity of 102.50 mg/g. Therefore, the resulting spherical ATP/SiO2 aerogels possessed multipath preparation and exhibited an efficient adsorption performance, with the potential to be applied as an adsorbent for dye wastewater.
Comparison of Corrosion Behavior of T91, 9Cr and 9CrAl ODS Steels in Liquid Pb
Authors: Chen Lingzhi , Xu Shuai , Schroer Carsten , Jia Haodong , Ruan Zhangshun , Qin Bo , Zhou Zhangjian , Long Bin
Published: March 2023

It is important to improve the liquid lead corrosion resistance of fuel cladding alloy for promoting the development of lead-based reactors. The corrosion behaviors of traditional T91 steel and similar oxide dispersion strengthen ODS-type steels with or without the addition of Al, and were examined and compared at 600 °C in static oxygen-controlled liquid Pb in this research. High-temperature liquid lead corrosion tests were carried out for 120 h, 240 h, 500 h, 1000 h, and 2000 h, respectively, for three prepared samples. After the experiment, the corrosion behavior was evaluated and compared mainly based on the aspects of appearance, corrosion depth, microstructure, and composition difference. It was found that just the ODS design did not show a positive effect on corrosion resistance, while the addition of Al is beneficial to improving the corrosion resistance of ODS steel. The maximum corrosion depth of 9CrAl ODS is only 51.8 μm after corrosion for 2000 h, which is much lower than that of 9Cr-ODS steel. A thin film containing Al/Cr formed in the corrosion area after adding Al in 9Cr ODS steel, which played a positive role in corrosion resistance.
Astaxanthin as a King of Ketocarotenoids: Structure, Synthesis, Accumulation, Bioavailability and Antioxidant Properties
Authors: Nair Anagha , Ahirwar Ankesh , Singh Shashikala , Lodhi Reeta , Lodhi Aishwarya , Rai Anshuman , Jadhav Dipak A , Harish  , Varjani Sunita , Singh Gurpreet , Marchand Justine , Schoefs Benoît , Vinayak Vandana
Published: March 2023

Astaxanthin (3,3-dihydroxy-β, β-carotene-4,4-dione) is a ketocarotenoid synthesized by Haematococcus pluvialis/lacustris, Chromochloris zofingiensis, Chlorococcum, Bracteacoccus aggregatus, Coelastrella rubescence, Phaffia rhodozyma, some bacteria (Paracoccus carotinifaciens), yeasts, and lobsters, among others However, it is majorly synthesized by Haematococcus lacustris alone (about 4%). The richness of natural astaxanthin over synthetic astaxanthin has drawn the attention of industrialists to cultivate and extract it via two stage cultivation process. However, the cultivation in photobioreactors is expensive, and converting it in soluble form so that it can be easily assimilated by our digestive system requires downstream processing techniques which are not cost-effective. This has made the cost of astaxanthin expensive, prompting pharmaceutical and nutraceutical companies to switch over to synthetic astaxanthin. This review discusses the chemical character of astaxanthin, more inexpensive cultivating techniques, and its bioavailability. Additionally, the antioxidant character of this microalgal product against many diseases is discussed, which can make this natural compound an excellent drug to minimize inflammation and its consequences.
Mucormycosis in a Patient with Severe COVID-19 Disease—The First Case Report in Romania and a Literature Review
Authors: Mahler Beatrice , Parliteanu Oana Andreea , Alexe Octavian , Rîșcă Popazu Corina , Ene Catalina Elena , Timar Bogdan , Constantinescu Tudor
Published: March 2023

Introduction: COVID-19 infection is often associated with a vast spectrum of opportunistic bacterial and fungal infections. Herein, we share a summary of the first case of COVID-19-associated mucormycosis (CAM) in a patient from Romania. Case presentation: A 51-year-old male non-smoker, with no known relevant medical history, who denied any previous alcohol use and was vaccinated against COVID-19 (complete scheme with Vaxzevria), was admitted to the hospital for severe COVID-19 infection. The first mucormycosis-related symptoms were reported on the eighth day of admission and were followed by the rapid deterioration of the patient’s condition and, consequently, death. The main aggravating factors, which were identified to be associated with the development of mucormycosis and with the poor outcome, were the association of severe COVID-19, new-onset COVID-19-triggered type 2 diabetes, and corticoid treatment for severe COVID-19. Conclusion: The association between severe COVID-19 and newly diagnosed type 2 diabetes, triggered by COVID-19 infection, increases the risk of severe opportunistic fungal infections and the associated mortality rates.
A Small-Angle Neutron Scattering, Calorimetry and Densitometry Study to Detect Phase Boundaries and Nanoscale Domain Structure in a Binary Lipid Mixture
Authors: Krzyzanowski Natalie , Porcar Lionel , Perez-Salas Ursula
Published: March 2023

Techniques that can probe nanometer length scales, such as small-angle neutron scattering (SANS), have become increasingly popular to detect phase separation in membranes. But to extract the phase composition and domain structure from the SANS traces, complementary information is needed. Here, we present a SANS, calorimetry and densitometry study of a mixture of two saturated lipids that exhibits solidus–liquidus phase coexistence: 1,2-dipalmitoyl-d62-sn-glycero-3-phosphocholine (dDPPC, tail-deuterated DPPC) and 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC). With calorimetry, we investigated the phase diagram for this system and found that the boundary traces for both multilamellar vesicles (MLVs) as well as 50 nm unilamellar vesicles overlap. Because the solidus boundary was mostly inaccessible by calorimetry, we investigated it by both SANS and molecular volume measurements for a 1:1 dDPPC:DLPC lipid mixture. From the temperature behavior of the molecular volume for the 1:1 dDPPC:DLPC mixture, as well as the individual molecular volume of each lipid species, we inferred that the liquidus phase consists of only fluid-state lipids while the solidus phase consists of lipids that are in gel-like states. Using this solidus–liquidus phase model, the SANS data were analyzed with an unrestricted shape model analysis software: MONSA. The resulting fits show irregular domains with dendrite-like features as those previously observed on giant unilamellar vesicles (GUVs). The surface pair correlation function describes a characteristic domain size for the minority phase that decreases with temperature, a behavior found to be consistent with a concomitant decrease in membrane mismatch between the liquidus and solidus phases.
Analysis of Microbial Communities in Membrane Biofilm Reactors Using a High-Density Microarray
Authors: Li Shilong , Duan Liang , Zhao Yang , Gao Fu , Hermanowicz Slawomir W.
Published: March 2023

Membrane biofilm reactors (MBfRs) have attracted more and more attention in the field of wastewater treatment due to their advantages of high mass transfer efficiency and low-carbon emissions. There are many factors affecting their nitrogen removal abilities, such as operation time, electron donor types, and operation modes. The operation time is directly related to the growth status of microorganisms, so it is very important to understand the effect of different operation times on microbial composition and community succession. In this study, two parallel H2-based MBfRs were operated, and differences in microbial composition, community succession, and NO3−-N removal efficiency were investigated on the 30th day and the 60th day of operation. The nitrogen removal efficiency of MBfRs with an operation time of 60 days was higher than that of MBfRs with an operation time of 30 days. Proteobacteria was the dominant phylum in both MBfRs; however, the composition of the microbial community was quite different. At the class level, the community composition of Proteobacteria was similar between the two MBfRs. Alphaproteobacteria was the dominant class in MBfR, and Betaproteobacteria and Gammaproteobacteria were also in high proportion. Combined with the analysis of microbial relative abundance and concentration, the similarity of microbial distribution in the MBfRs was very low on day 30 and day 60, and the phylogenetic relationships of the top 50 dominant universal bacteria and Proteobacteria were different. Although the microbial concentration decreased with the extension of the operation time, the microbial abundance and diversity of specific functional microorganisms increased further. Therefore, the operation time had a significant effect on microbial composition and community succession.
Green Method for the Selective Electromembrane Extraction of Parabens and Fluoroquinolones in the Presence of NSAIDs by Using Biopolymeric Chitosan Films
Authors: Román-Hidalgo Cristina , Martín-Valero María , López-Pérez Germán , Villar-Navarro Mercedes
Published: March 2023

A chitosan biopolymeric membrane was successfully used as a support in a green electromembrane extraction procedure for the simultaneous and selective extraction of seven parabens and three fluoroquinolones in the presence of three non-steroidal anti-inflammatory drugs. The optimal experimental conditions (10 mL donor phase and 50 μL acceptor phase, pH 10 in both phases; 80 V of applied voltage during 15 min of extraction time) were determined, providing high enrichment factors for six of the studied parabens (EF ≥ 90) and the three fluoroquinolones (EF ≥ 50). Wide linear concentration ranges (0.5–500 μg L−1), good linearity (>97%), low limits of detection (0.2–1.1 μg L−1), and good repeatability (relative standard deviation values 4–10%) were achieved. The proposed method was successfully applied for the extraction of the target analytes from different kinds of water samples (river, lake, and swimming pool). The usage of a chitosan membrane in the extraction process presents many advantages, as it is a biodegradable and versatile support, offering a good alternative to commercial plastic materials commonly used in this methodology and these procedures.
Experimental Study and Modeling of Beer Dealcoholization via Reverse Osmosis
Authors: Varga Áron , Bihari-Lucena Eszter , Ladányi Márta , Szabó-Nótin Beatrix , Galambos Ildikó , Koris András
Published: March 2023

The goals of the present investigation are to study and to model pale lager beer dealcoholization via reverse osmosis (RO). Samples were dealcoholized at a temperature of 15 ± 1 °C. An Alfa Laval RO99 membrane with a 0.05 m2 surface was used. The flux values were measured during the separations. The ethanol content, extract content, bitterness, color, pH, turbidity, and dynamic viscosity of beer and permeate samples were measured. The initial flux values were determined using linear regression. The initial ethanol flux (JEtOH 0) values were calculated from the initial flux values and the ethanol content values. A 2P full factorial experimental design was applied, and the factors were as follows: transmembrane pressure (TMP): 10, 20, 30 bar; retentate flow rate (Q): 120, 180, 240 L/h; JEtOH 0 was considered as the response. The effect sizes of the significant parameters were calculated. The global maximum of the objective function was found using a self-developed Grid Search code. The changes in the analytical parameters were appropriate. The TMP had a significant effect, while the Q had no significant effect on the JEtOH 0. The effect size of the TMP was 1.20. The optimal value of the factor amounted to TMP = 30 bar. The predicted JEtOH 0 under the above conditions was 121.965 g/m2 h.
Robot-Assisted Cold and Warm Incremental Sheet Forming of Aluminum Alloy 6061: A Comparative Study
Authors: Singh Ravi Prakash , Kumar Santosh , Pande Sarang , Salunkhe Sachin , Ragab Adham E. , Singh Pankaj Kumar , Meraz Md , Davim J. Paulo
Published: March 2023

Incremental sheet forming (ISF) requires no or partial dies for sheet metal fabrication and is widely used for small batch production. In this process, necking is either suppressed or delayed due to the localized nature of tool–sheet contact; hence, more strains than conventional stamping and deep drawing are obtained. In the present study, two variations of ISF, namely cold ISF (CISF) and warm ISF (WISF), are compared. First, FEA modeling is carried out on ABAQUS to reach the forming forces involved in the process. It is found that WISF reduces the forming forces. The temperature for WISF is maintained at 180 °C. Following the simulation analysis, tests are carried out. The forming force in WISF is 55.77% less than that in CISF. The part fabricated by CISF is slightly more substantial than that by WISF; however, more forming depth can be achieved by WISF. There is a more uniform thickness distribution in the case of CISF than in WISF. However, the surface quality of the CISF product is inferior to that of WISF. It is observed that there is reduced forming force, increased formability, and better strain distribution in WISF compared to CISF. However, post-processing heat treatment and surface polishing of the formed parts is required to restore their mechanical properties.
Mechanism Correlating Microstructure and Wear Behaviour of Ti-6Al-4V Plate Produced Using Selective Laser Melting
Authors: Jeyaprakash Natarajan , Yang Che-Hua , Prabu Govindarajan , Radhika Nachimuthu
Published: March 2023

In the present study, a dry sliding wear test has been conducted to analyse the wear rate of Ti-6Al-4V alloy specimens which were fabricated using selective laser melting and conventional methods. Microstructure, micro- and nanohardness, and wear behaviour of selective laser melting specimens were investigated and compared with commercially available conventionally fabricated Ti-6Al-4V specimens. The mechanism correlating microstructure and wear behaviour of conventional and selective laser melting based Ti-6Al-4V specimens have been explained. The microhardness of the selective laser melting specimen was improved by around 22.4% over the specimen from the conventional method. The selective laser melting specimen showed broadened peaks and an increase in intensity height greater than that of the conventional specimen due to the presence of the martensite phase. The selective laser melting specimen possessed 41.4% higher nanohardness than that of the conventional specimen. The selective laser melting specimen had a 62.1% lower wear rate when compared to that of the conventional specimen. The selective laser melting specimen exhibited 62.7% less coefficient of friction than that of the conventional specimen at a 50 N load with 1.2 m/s sliding velocities. The finer needle-like microstructures of the specimen produced using the selective laser melting process had higher wear resistance, as it had higher hardness than the conventional specimen.
Molecular, Metabolic, and Nutritional Changes after Metabolic Surgery in Obese Diabetic Patients (MoMen): A Protocol for a Multicenter Prospective Cohort Study
Authors: Fazliana Mansor , Nor Hanipah Zubaidah , Mohd Yusof Barakatun Nisak , Zainal Abidin Nur Azlin , Tan You Zhuan , Mohkiar Farah Huda , Liyana Ahmad Zamri , Mohd Naeem Mohd Nawi , Mohmad Misnan Norazlan , Ahmad Haron , Draman Mohd Shazli , Tsen Poh Yue , Lim Shu Yu , Gee Tikfu
Published: March 2023

Metabolic surgery is an essential option in the treatment of obese patients with type 2 diabetes (T2D). Despite its known advantages, this surgery still needs to be introduced in Malaysia. In this prospective study, the pathophysiological mechanisms at the molecular level will be studied and the metabolomics pathways of diabetes remission will be explored. The present study aims to evaluate the changes in the anthropometric measurements, body composition, phase angle, diet intake, biochemistry parameters, adipokines, microRNA, and metabolomics, both pre- and post-surgery, among obese diabetic patients in Malaysia. This is a multicenter prospective cohort study that will involve obese patients (n = 102) with a body mass index (BMI) of ≥25 kg/m2 (Asian BMI categories: WHO/IASO/IOTF, 2000) who will undergo metabolic surgery. They will be categorized into three groups: non-diabetes, prediabetes, and diabetes. Their body composition will be measured using a bioimpedance analyzer (BIA). The phase angle (PhA) data will be analyzed. Venous blood will be collected from each patient for glycated hemoglobin (HbA1c), lipids, liver, renal profile, hormones, adipokines, and molecular and metabolomics analyses. The serum microRNA will be measured. A gene expression study of the adipose tissue of different groups will be conducted to compare the groups. The relationship between the 1HNMR-metabolic fingerprint and the patients’ lifestyles and dietary practices will be determined. The factors responsible for the excellent remission of T2D will be explored in this study.
Corinthian Currants Supplementation Restores Serum Polar Phenolic Compounds, Reduces IL-1beta, and Exerts Beneficial Effects on Gut Microbiota in the Streptozotocin-Induced Type-1 Diabetic Rat
Authors: Kompoura Vasiliki , Prapa Ioanna , Vasilakopoulou Paraskevi B. , Mitropoulou Gregoria , Nelios Grigorios , Balafas Evangelos , Kostomitsopoulos Nikolaos , Chiou Antonia , Karathanos Vaios T. , Bezirtzoglou Eugenia , Kourkoutas Yiannis , Yanni Amalia E.
Published: March 2023

The present study aimed at investigating the possible benefits of a dietary intervention with Corinthian currants, a rich source of phenolic compounds, on type 1 diabetes (T1D) using the animal model of the streptozotocin-(STZ)-induced diabetic rat. Male Wistar rats were randomly assigned into four groups: control animals, which received a control diet (CD) or a diet supplemented with 10% w/w Corinthian currants (CCD), and diabetic animals, which received a control diet (DCD) or a currant diet (DCCD) for 4 weeks. Plasma biochemical parameters, insulin, polar phenolic compounds, and inflammatory factors were determined. Microbiota populations in tissue and intestinal fluid of the caecum, as well as fecal microbiota populations and short-chain fatty acids (SCFAs), were measured. Fecal microbiota was further analyzed by 16S rRNA sequencing. The results of the study showed that a Corinthian currant-supplemented diet restored serum polar phenolic compounds and decreased interleukin-1b (IL-1b) (p < 0.05) both in control and diabetic animals. Increased caecal lactobacilli counts (p < 0.05) and maintenance of enterococci levels within normal range were observed in the intestinal fluid of the DCCD group (p < 0.05 compared to DCD). Higher acetic acid levels were detected in the feces of diabetic rats that received the currant diet compared to the animals that received the control diet (p < 0.05). Corinthian currant could serve as a beneficial dietary component in the condition of T1D based on the results coming from the animal model of the STZ-induced T1D rat.
Neurodegeneration, Mitochondria, and Antibiotics
Authors: Suárez-Rivero Juan M. , López-Pérez Juan , Muela-Zarzuela Inés , Pastor-Maldonado Carmen , Cilleros-Holgado Paula , Gómez-Fernández David , Álvarez-Córdoba Mónica , Munuera-Cabeza Manuel , Talaverón-Rey Marta , Povea-Cabello Suleva , Suárez-Carrillo Alejandra , Piñero-Pérez Rocío , Reche-López Diana , Romero-Domínguez José M. , Sánchez-Alcázar José Antonio
Published: March 2023

Neurodegenerative diseases are characterized by the progressive loss of neurons, synapses, dendrites, and myelin in the central and/or peripheral nervous system. Actual therapeutic options for patients are scarce and merely palliative. Although they affect millions of patients worldwide, the molecular mechanisms underlying these conditions remain unclear. Mitochondrial dysfunction is generally found in neurodegenerative diseases and is believed to be involved in the pathomechanisms of these disorders. Therefore, therapies aiming to improve mitochondrial function are promising approaches for neurodegeneration. Although mitochondrial-targeted treatments are limited, new research findings have unraveled the therapeutic potential of several groups of antibiotics. These drugs possess pleiotropic effects beyond their anti-microbial activity, such as anti-inflammatory or mitochondrial enhancer function. In this review, we will discuss the controversial use of antibiotics as potential therapies in neurodegenerative diseases.
Lipidomic Profiling Reveals Concerted Temporal Patterns of Functionally Related Lipids in Aedes aegypti Females Following Blood Feeding
Authors: Lau Meng-Jia , Nie Shuai , Yang Qiong , Harshman Lawrence G. , Mao Cungui , Williamson Nicholas A. , Hoffmann Ary A.
Published: March 2023

We conducted a lipidomic analysis of the whole body of female Aedes aegypti mosquitoes at different time points over the course of feeding and reproduction. There were temporal biphasic increases of more than 80% of lipids identified at the time of feeding and from 16 h to 30 h post blood meal (PBM). During these two increases, the abundance of many lipids dropped while body weight remained stable, probably reflecting blood lipid digestion and the synthesis of vitellogenin in this period. A concerted temporal pattern was particularly strong at the second peak for membrane and signalling lipids such as phosphatidylethanolamine (PE), phosphatidylinositol (PI), cardiolipin (CL), hexosylceramide (HexCer) and lyso-phosphatidic acid (LPA). Lyso-glycerophospholipids showed three distinct change patterns that are functionally related: Lyso-PE and Lyso-phosphatidylcholine (LPC), which are membrane lipids, showed little change; LPA, a signalling lipid, showed a significant increase from 16 to 30 h PBM; Lyso-PI, a bioactive lipid, and both lyso-phosphatidylglycerol (LPG) and lyso-phosphatidylserine (LPS), which are bacterial membrane lipids, showed one significant increase from the time of feeding to 16 h post blood meal. The result of our study on the anautogenous insect Ae. aegypti point to specific lipids likely to be important in the reproductive process with a role in the formation and growth of ovarian follicles.
A Novel Atomically Resolved Scanning Tunneling Microscope Capable of Working in Cryogen-Free Superconducting Magnet
Authors: Geng Tao , Wang Jihao , Meng Wenjie , Zhang Jing , Feng Qiyuan , Hou Yubin , Lu Qingyou
Published: March 2023

We present a novel homebuilt scanning tunneling microscope (STM) with atomic resolution integrated into a cryogen-free superconducting magnet system with a variable temperature insert. The STM head is designed as a nested structure of double piezoelectric tubes (PTs), which are connected coaxially through a sapphire frame whose top has a sample stage. A single shaft made of tantalum, with the STM tip on top, is held firmly by a spring strip inside the internal PT. The external PT drives the shaft to the tip–sample junction based on the SpiderDrive principle, and the internal PT completes the subsequent scanning and imaging work. The STM head is simple, compact, and easy to assemble. The excellent performance of the device was demonstrated by obtaining atomic-resolution images of graphite and low drift rates of 30.2 pm/min and 41.4 pm/min in the X–Y plane and Z direction, respectively, at 300K. In addition, we cooled the sample to 1.6 K and took atomic-resolution images of graphite and NbSe2. Finally, we performed a magnetic field sweep test from 0 T to 9 T at 70 K, obtaining distinct graphite images with atomic resolution under varying magnetic fields. These experiments show our newly developed STM’s high stability, vibration resistance, and immunity to high magnetic fields.
Analysis of Degradation of Electromigration Reliability of Au-Al and OPM Wire Bonded Contacts at 250 °C Using Resistance Monitoring Method
Authors: Li Xueqin , Gao Linchun , Ni Tao , Zhou Jingnan , Li Xiaojing , Li Yifan , Xu Lida , Wang Runjian , Zeng Chuanbin , Li Bo , Luo Jiajun , Li Jing
Published: March 2023

The ongoing trend towards miniaturization and increased packaging density has exacerbated the reliability problem of Au-Al heterogeneous metal bonding structures in high-temperature environments, where extreme temperatures and high current pose a serious challenge. In order to address this issue, the present study aims to investigate the electromigration reliability of Au-Al bonding by comparing the conventional heterogeneous contacts with OPM structures, which are homogeneous contacts. A novel bonding layout was developed to precisely detect the resistance and obtain stage changes in electromigration. The experimental results demonstrated that the relative resistance shift of Au-Al bonding at 250 °C was 98.7%, while CrAu and NiPdAu OPM structures exhibited only 46.1% and 2.93% shifts, which suggests that the reliability of OPM structures was improved by a factor of 2.14 and 33.6, respectively. The degradation of Au-Al bonding was attributed to the large cracks observed at the bonding interface and lateral consumption of Al elements. In contrast, OPM structures only exhibited tiny voids and maintained a better bonding state overall, indicating that homogeneous metal contacts have better immunity to electromigration. Furthermore, this study also observed the polarity effect of electromigration and analyzed the impact of NiPdAu thickness on reliability. Overall, this research provides a novel approach and an insightful theoretical reference for addressing the bottleneck of high-temperature electromigration reliability in high-temperature sensor packaging.
Sub PPM Detection of NO2 Using Strontium Doped Bismuth Ferrite Nanostructures
Authors: Dmonte David John , Bhardwaj Aman , Wilhelm Michael , Fischer Thomas , Kuřitka Ivo , Mathur Sanjay
Published: March 2023

The present work investigates the NO2 sensing properties of acceptor-doped ferrite perovskite nanostructures. The Sr-doped BiFeO3 nanostructures were synthesized by a salt precursor-based modified pechini method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The synthesized materials were drop coated to fabricate chemoresistive gas sensors, delivering a maximum sensitivity of 5.2 towards 2 ppm NO2 at 260 °C. The recorded values of response and recovery time are 95 s and 280 s, respectively. The sensor based on Bi0.8Sr0.2FeO3–δ (BSFO) that was operated was shown to have a LOD (limit of detection) as low as 200 ppb. The sensor proved to be promising for repeatability and selectivity measurements, indicating that the Sr doping Bismuth ferrite could be a potentially competitive material for sensing applications. A relevant gas-sensing mechanism is also proposed based on the surface adsorption and reaction behavior of the material.
Reduction of Friction Using Microabrasive Air Jet Machining
Authors: Lee Sungcheul , Choi Soochang , Lee Hyeon Hwa , Ro Seung-Kook
Published: March 2023

In this paper, we introduce a microabrasive air jet (micro-AAJ) machining system and describe machining results obtained while using it. Our research activities have focused on the development of micro-AAJ machining methods for friction reduction without requiring a mask. Through this study, we want to show that such processing is possible without a mask when using the AAJ method. In this paper, a micro-AAJ machining system is introduced, and the processing results are described. By comparing the friction coefficient of texturing under various conditions, the relative relationship between the surface shape and the friction coefficient can be identified. We investigated the effect of the relationship between rotating velocity, traverse speed, density of the patterned area and injection pressure on friction. The friction is decreased with a low traverse speed and high-density patterned area under high-speed driving conditions, as verified by experiments using a friction test system.
Semi-VOCs of Wood Vinegar Display Strong Antifungal Activities against Oomycete Species Globisporangium ultimum and Pythium aphanidermatum
Authors: Chenari Bouket Ali , Narmani Abolfazl , Sharifi Kasra , Naeimi Shahram , Afshar Mogaddam Mohammad Reza , Hamidi Ali Asghar , Luptakova Lenka , Alenezi Faizah N. , Belbahri Lassaad
Published: March 2023

Plant disease outbreaks are increasingly exacerbated by climate change and the conditions of stress combinations. They are negatively affecting crop yield and driving threats to food security in many areas of the world. Although synthetic pesticides offer relative success in the control of pests and plant diseases, they are often overused, and this method faces numerous drawbacks, including environmental toxicity, soil degradation, and adverse effects on human health. Therefore, alternatives are being developed and examined, including the biocontrol of pests and pathogens and biomass pyrolysis leading to wood vinegar that has shown great promise in agriculture and organic farming. However, while wood vinegar use is expanding and allows the control of numerous pests and bacterial and fungal diseases, its application to control oomycete diseases is limited. This study aimed to test wood vinegar for the control of oomycete plant pathogens from which six wood vinegars of pistachio, pomegranate, almond, pine, cypress, and walnut were produced. The inhibitory effects of volatile metabolites (semi-VOCs) of different wood vinegars concentrations (100%, 50%, 25%, 12.5%, and 6.25%) were examined against the hyphal growth of Globisporangium ultimum and Pythium aphanidermatum isolates. An in vitro analysis unambiguously demonstrated that for Globisporangium ultimum, the wood vinegar semi-VOCs of almond, pistachio (C 100% and 50%), and walnut (C 100%) totally inhibited mycelial growth. On the other hand, Pythium aphanidermatum, pistachio (C 100%, 50%, and 25%), and cypress (C 100%) expressed their abilities to completely inhibit the mycelial growth. Other treatments, including relevant concentrations of pine and pomegranate significantly inhibited the growth of mycelia of both species compared to the control (p ≤ 0.05). Therefore, wood vinegar could be considered a natural and organic product to use in agriculture to cope not only against pests, bacterial and fungal pests but also against emerging oomycete plant diseases.
The Distribution Regularity and Flotation Study of Niobium-Bearing Minerals in Baiyun Obo
Authors: Zhang Min , Chen Fangfang , Yan Guoying , Li Hongjing , Li Jing , Peng Guan , Yu Hongdong
Published: March 2023

The characteristics of Baiyun Obo niobium-bearing minerals are complex physicochemical properties that make the beneficiation of niobium minerals extremely difficult. In this paper, X-ray diffraction, X-ray fluorescence and mineral liberation analyzer (MLA) systems were used to study the niobium occurrence state and distribution of niobium-bearing minerals in the samples from Baiyun Obo. The results show that the chemical and mineral compositions of the sample are complex, with a Nb2O5 grading of 0.24%. There are many kinds of niobium minerals, including ilmenorutile, nioboaeschynite-Nd, baotite, latrappite, euxenite-Y, fergusonite and columbite-Mn, and the highest mass fraction of 0.55% is achieved with Nb in nioboaeschynite-Nd, followed by the mass fraction of ilmenorutile (0.33%). All of the niobium-containing minerals demonstrate a low degree of dissociation. Flotation experiments explored the optimal flotation conditions for HOBA (1-hydroxyoctyl-1,1-bisphosphonic acid) as a flotation collector for Baiyun Obo niobium minerals, which is able to increase the grade of Nb2O5 in the concentrate to 1.31%. The optimal use conditions of the reagent are pH 3.5–4.5, and the amount of the collector is 1000 g/t. By further optimizing the beneficiation process and reagent system, ilmenorutile and nioboaeschynite-Nd were significantly enriched in the concentrate, which suggested that HOBA can efficiently increase the grade of Nb2O5 in the concentrate.