bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards a Uniform Welding Quality: A Novel Weaving Welding Control Algorithm Based on Constant Heat Input
Authors: Lu Hong , Wu Zidong , Zhang Yongquan , Wang Yongjing , Liu Shu , Huang He , Liu Meng , Liu Shijie
Published: May 2022

The weaving welding process is a key method used to improve the welding quality in multi-layer and multi-pass welding processes using robots. However, the heat-input fluctuation in the weaving welding process restricts its development. In this paper, we developed a novel weaving welding control algorithm to maintain a constant weld heat input through velocity adaptive planning. First, the heat consumption during the weaving welding was modeled to describe the influence of weaving parameters on the weld heat input. Then, based on the obtained relationship between the weld heat input and the weaving parameters, a velocity-adaptive trajectory planning strategy was proposed by leveraging the transformation matrix derived from the relationship between the workpiece and the robot co-ordinate systems. The simulation and experimental results show that the proposed strategy can compensate for the weaving parameters to maintain a constant heat input based on heat consumption and improve the quality of the robotic multi-layer and multi-pass welding process.
Optimal Design of Ceramic Based Hip Implant Composites Using Hybrid AHP-MOORA Approach
Authors: Singh Tej , Goswami Chandramani , Patnaik Amar , Lendvai László
Published: May 2022

Designing excellent hip implant composite material with optimal physical, mechanical and wear properties is challenging. Improper hip implant composite design may result in a premature component and product failure. Therefore, a hybrid decision-making tool was proposed to select the optimal hip implant composite according to several criteria that are probably conflicting. In varying weight proportions, a series of hip implant composite materials containing different ceramics (magnesium oxide, zirconium oxide, chromium oxide, silicon nitride and aluminium oxide) were fabricated and evaluated for wear and physicomechanical properties. The density, void content, hardness, indentation depth, elastic modulus, compressive strength, wear, and fracture toughness values were used to rank the hip implant composites. It was found that the density and void content of the biocomposites remain in the range of 3.920–4.307 g/cm3 and 0.0021–0.0089%, respectively. The composite without zirconium oxide exhibits the lowest density (3.920 g/cm3), while the void content remains lowest for the composite having no chromium oxide content. The highest values of hardness (28.81 GPa), elastic modulus (291 GPa) and fracture toughness (11.97 MPa.m1/2) with the lowest wear (0.0071 mm3/million cycles) were exhibited by the composites having 83 wt.% of aluminium oxide and 10 wt.% of zirconium oxide. The experimental results are compositional dependent and without any visible trend. As a result, selecting the best composites among a group of composite alternatives becomes challenging. Therefore, a hybrid AHP-MOORA based multi-criteria decision-making approach was adopted to choose the best composite alternative. The AHP (analytic hierarchy process) was used to calculate the criteria weight, and MOORA (multiple objective optimisation on the basis of ratio analysis) was used to rank the composites. The outcomes revealed that the hip implant composite with 83 wt.% aluminium oxide, 10 wt.% zirconium oxide, 5 wt.% silicon nitride, 3 wt.% magnesium oxide, and 1.5 wt.% chromium oxide had the best qualities. Finally, sensitivity analysis was conducted to determine the ranking’s robustness and stability concerning the criterion weight.
Effect of Biochar on Metal Distribution and Microbiome Dynamic of a Phytostabilized Metalloid-Contaminated Soil Following Freeze–Thaw Cycles
Authors: Radziemska Maja , Gusiatin Mariusz Z. , Cydzik-Kwiatkowska Agnieszka , Blazejczyk Aurelia , Kumar Vinod , Kintl Antonin , Brtnicky Martin
Published: May 2022

In the present paper the effectiveness of biochar-aided phytostabilization of metal/metalloid-contaminated soil under freezing–thawing conditions and using the metal tolerating test plant Lolium perenne L. is comprehensively studied. The vegetative experiment consisted of plants cultivated for over 52 days with no exposure to freezing–thawing in a glass greenhouse, followed by 64 days under freezing–thawing in a temperature-controlled apparatus and was carried out in initial soil derived from a post-industrial urban area, characterized by the higher total content of Zn, Pb, Cu, Cr, As and Hg than the limit values included in the classification provided by the Regulation of the Polish Ministry of Environment. According to the substance priority list published by the Toxic Substances and Disease Registry Agency, As, Pb, and Hg are also indicated as being among the top three most hazardous substances. The initial soil was modified by biochar obtained from willow chips. The freeze–thaw effect on the total content of metals/metalloids (metal(-loid)s) in plant materials (roots and above-ground parts) and in phytostabilized soils (non- and biochar-amended) as well as on metal(-loid) concentration distribution/redistribution between four BCR (community bureau of reference) fractions extracted from phytostabilized soils was determined. Based on metal(-loid)s redistribution in phytostabilized soils, their stability was evaluated using the reduced partition index (Ir). Special attention was paid to investigating soil microbial composition. In both cases, before and after freezing–thawing, biochar increased plant biomass, soil pH value, and metal(-loid)s accumulation in roots, and decreased metal(-loid)s accumulation in stems and total content in the soil, respectively, as compared to the corresponding non-amended series (before and after freezing–thawing, respectively). In particular, in the phytostabilized biochar-amended series after freezing–thawing, the recorded total content of Zn, Cu, Pb, and As in roots substantially increased as well as the Hg, Cu, Cr, and Zn in the soil was significantly reduced as compared to the corresponding non-amended series after freezing–thawing. Moreover, exposure to freezing–thawing itself caused redistribution of examined metal(-loid)s from mobile and/or potentially mobile into the most stable fraction, but this transformation was favored by biochar presence, especially for Cu, Pb, Cr, and Hg. While freezing–thawing greatly affected soil microbiome composition, biochar reduced the freeze–thaw adverse effect on bacterial diversity and helped preserve bacterial groups important for efficient soil nutrient conversion. In biochar-amended soil exposed to freezing–thawing, psychrotolerant and trace element-resistant genera such as Rhodococcus sp. or Williamsia sp. were most abundant.
Experimental Investigation on Seepage Characteristics of Clay–Structure Interface after Shear Deformation
Authors: Tan Jiacheng , Shen Zhenzhong , Xu Liqun , Zhang Hongwei , He Yingming
Published: May 2022

There exist shear and seepage behaviors on the interface between clay core and concrete slab in clay core dams. In order to investigate the seepage characteristics of the clay–structure interface after shear deformation, a shear-seepage test system is proposed, in which the seepage direction is perpendicular to the shear direction. The shear test and shear-seepage test are performed on clay–metal and clay–mortar interfaces under different normal stresses (100, 200, 400, 800, and 1600 kPa). The shear stress-deformation curves of two clay–structure interfaces exhibit softening behavior and residual friction behavior. The interface roughness can enhance peak and residual shear strength and increase peak displacement. The shear-seepage test results show that specimen permeability decreases first and then increases to a stable value as shear deformation increases under low normal stress, while it decreases continuously and then retains stability under high normal stress. The interface roughness enhances specimen permeability under low normal stress, whereas it has a weak effect on specimen permeability under high normal stress. Compared with initial permeability, shear deformation reduces specimen permeability rather than raise it. The ratio of stabilized permeability coefficient to initial value ranges from 0.6 to 0.8. The clay–structure interface still has a good resistance to seepage failure after shear deformation. The shear dilation features and interface pore decrease caused by shear behavior are the internal attributions of clay–structure specimen permeability evolution.
Adverse Effects of Using Metallurgical Slags as Supplementary Cementitious Materials and Aggregate: A Review
Authors: Zhao Qiang , Pang Lang , Wang Dengquan
Published: May 2022

This paper discusses a sustainable way to prepare construction materials from metallurgical slags. Steel slag, copper slag, lead-zinc slag, and electric furnace ferronickel slag are the most common metallurgical slags that could be used as supplementary cementitious materials (SCMs) and aggregates. However, they have some adverse effects that could significantly limit their applications when used in cement-based materials. The setting time is significantly delayed when steel slag is utilized as an SCM. With the addition of 30% steel slag, the initial setting time and final setting time are delayed by approximately 60% and 40%, respectively. Because the specific gravity of metallurgical slags is 10–40% higher than that of natural aggregates, metallurgical slags tend to promote segregation when utilized as aggregates. Furthermore, some metallurgical slags deteriorate the microstructure of hardened pastes, resulting in higher porosity, lower mechanical properties, and decreased durability. In terms of safety, there are issues with the soundness of steel slag, the alkali-silica reaction involving cement and electric furnace ferronickel slag, and the environmental safety concerns, due to the leaching of heavy metals from copper slag and lead-zinc slag.
Experiment and Numerical Simulation of Damage Progression in Transparent Sandwich Structure under Impact Load
Authors: Wang Mufei , Li Yuting , Luo Haoshun , Zheng Xiaoxia , Li Zhiqiang
Published: May 2022

Crack initiation and propagation is a long-standing difficulty in solid mechanics, especially for elastic brittle materials. A new type of transparent sandwich structure, with a magnesium–aluminum spinel ceramic glass as the outer structure, was proposed in this paper. Its dynamic response was studied by high-speed impact experiments and numerical simulations of peridynamics under impact loads, simultaneously. In the experiments, a light gas cannon was used to load the projectile to 180 m/s, and the front impacted the transparent sandwich structure. In the numerical simulations, the discontinuous Galerkin peridynamics method was adopted to investigate the dynamic response of the transparent sandwich structure. We found that both the impact experiments and the numerical simulations could reproduce the crack propagation process of the transparent sandwich structure. The radial cracks and circumferential cracks of the ceramic glass layer and the inorganic glass layer were easy to capture. Compared with the experiments, the numerical simulations could easily observe the damage failure of every layer and the splashing of specific fragments of the transparent sandwich structure. The ceramic glass layer and the inorganic glass layer absorbed the most energy in the impact process, which is an important manifestation of the impact resistance of the transparent sandwich structure.
Molecular Dynamics Simulation Study on the Interactions of Mixed Cationic/Anionic Collectors on Muscovite (001) Surface in Aqueous Solution
Authors: Di Yuli , Jiang Ao , Huang Haiyan , Deng Lin , Zhang Dafu , Deng Wenwei , Wang Rui , Luo Qian , Chen Shanhua
Published: May 2022

In this study, the adsorption mechanisms of dodecylamine hydrochloride(DDAHC), sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate(SDBS), and their mixed anionic/cationic collectors at ten different molar ratios on a muscovite (Mcv) surface in neutral aqueous solution were assessed by molecular dynamics simulations (MDS). According to the snapshot, interaction energy, radial distribution function (RDF), and density profile between the Mcv surface and collector molecules, the individual DDAHC collector was an effective collector for the flotation of Mcv. The molar ratio of anionic/cationic collectors was determined to be an essential factor in the flotation recovery of Mcv. The DDAHC collector was involved in the adsorption of the mixed anionic/cationic collectors on the Mcv (001) surface, whereas SDS and SDBS collectors were co-adsorbed with DDAHC. The mixed cationic/anionic collector showed the best adsorption on the Mcv surface in a molar ratio of 2. Additionally, SDBS, which has one more benzene ring than SDS, was more likely to form spherical micelles with DDAHC, thus resulting in better adsorption on the Mcv surface. The results of micro-flotation experiments indicated that the DDAHC collector could improve the flotation recovery of Mcv in neutral aqueous solution, which was in agreement with MDS-derived findings. In conclusion, DDAHC alone is the optimum collector for Mcv flotation under the neutral aqueous conditions, while the mixture of DDAHC and SDBS collectors (molar ratio = 2:1) exhibits the similar flotation performance.
Electrical and Thermal Characteristics of AlGaN/GaN HEMT Devices with Dual Metal Gate Structure: A Theoretical Investigation
Authors: Qu Yongfeng , Deng Ningkang , Yuan Yuan , Hu Wenbo , Liu Hongxia , Wu Shengli , Wang Hongxing
Published: May 2022

The electrical and thermal characteristics of AlGaN/GaN high-electron mobility transistor (HEMT) devices with a dual-metal gate (DMG) structure are investigated by electrothermal simulation and compared with those of conventional single-metal gate (SMG) structure devices. The simulations reveal that the DMG structure devices have a 10-percent higher transconductance than the SMG structure devices when the self-heating effect is considered. In the meantime, employing the DMG structure, a decrease of more than 11% in the maximum temperature rise of the devices can be achieved at the power density of 6 W/mm. Furthermore, the peak in heat generation distribution at the gate edge of the devices is reduced using this structure. These results could be attributed to the change in the electric field distribution at the gate region and the suppression of the self-heating effect. Therefore, the electrical and thermal performances of AlGaN/GaN HEMT devices are improved by adopting the DMG structure.
Al-Doped SrMoO3 Perovskites as Promising Anode Materials in Solid Oxide Fuel Cells
Authors: Cascos Vanessa , Fernández-Díaz María Teresa , Alonso José Antonio
Published: May 2022

Two perovskite materials with SrMo1−xAlxO3−δ (x = 0.1, 0.2) compositions have been synthesized by reduction from the corresponding scheelite phases, with SrMo1−xAlxO4−δ stoichiometry; the pertinent characterization shows that the defective perovskites can be used as anode materials in solid oxide fuel cells, providing maximum output power densities of 633 mW/cm2 for x = 0.2. To correlate structure and properties, a neutron powder diffraction investigation was carried out for both perovskite and scheelite phases. Both perovskites are cubic, defined in the Pm-3m space group, displaying a random distribution of Mo and Al cations over the 1a sites of the structure. The introduction of Al at Mo positions produced conspicuous amounts of oxygen vacancies in the perovskite, detected by neutrons. This is essential to induce ionic diffusion, providing a mixed ionic and electronic conduction (MIEC), since in MIEC electrodes, charge carriers are combined in one single phase and the ionic conductivity can be one order of magnitude higher than in a conventional material. The thermal expansion coefficients of the reduced and oxidized samples demonstrated that these materials perfectly match with the La0.8Sr0.2Ga0.83Mg0.17O3−δ electrolyte, La0.4Ce0.6O2−δ buffer layer and other components of the cell. Scanning electron microscopy after the test in a real solid oxide fuel cell showed a very dense electrolyte and porous electrodes, essential requirements for this type of fuel. SrMo1−xAlxO3−δ perovskites are, thus, a good replacement of conventional biphasic cermet anodes in solid oxide fuel cells.
Evaluation of Effect of Thermoplastic Polyurethane (TPU) on Crumb Rubber Modified (CRM) Asphalt Binder
Authors: Yun Jihyeon , Mazumder Mithil , Na Il-Ho , Lee Moon-Sup , Kim Hyun Hwan
Published: May 2022

Crumb rubber binder with thermoplastic polyurethane (TPU) has been experimented with to characterize the performance properties considering the workability, rutting, fatigue cracking and cracking resistance at low temperatures depending on the temperatures and aging states. Physical and rheological properties were evaluated to proceed with the study by applying Superpave asphalt binder testing and multi-stress creep recovery (MSCR). Based on the targeted experiments, the binder samples were produced at three aging states (original, short-term aged and long-term aged) using a rolling thin film oven (RTFO) and pressure aging vessel (PAV). The results revealed that (i) the addition of TPU into CRM binders has a potential effect on increasing viscoelasticity at the original condition, (ii) CRM binders containing TPU showed improved anti-aging performance based on results of RTFO residues and (iii) the inclusion of TPU made it possible for CRM asphalt binder to improve its fatigue and cracking resistance at low temperature.
Non-Thermal Plasma Reduction of Ag+ Ions into Silver Nanoparticles in Open Atmosphere under Statistically Optimized Conditions for Biological and Photocatalytic Applications
Authors: Altaf Noor Ul Huda , Naz Muhammad Yasin , Shukrullah Shazia , Ghamkhar Madiha , Irfan Muhammad , Rahman Saifur , Jakubowski Tomasz , Alqurashi Esam A. , Glowacz Adam , Mahnashi Mater H.
Published: May 2022

An environmentally friendly non-thermal DC plasma reduction route was adopted to reduce Ag+ ions at the plasma–liquid interface into silver nanoparticles (AgNPs) under statistically optimized conditions for biological and photocatalytic applications. The efficiency and reactivity of AgNPs were improved by statistically optimizing the reaction parameters with a Box–Behnken Design (BBD). The size of the AgNPs was chosen as a statistical response parameter, while the concentration of the stabilizer, the concentration of the silver salt, and the plasma reaction time were chosen as independent factors. The optimized parameters for the plasma production of AgNPs were estimated using a response surface methodology and a significant model p < 0.05. The AgNPs, prepared under optimized conditions, were characterized and then tested for their antibacterial, antioxidant, and photocatalytic potentials. The optimal conditions for these three activities were 3 mM of stabilizing agent, 5 mM of AgNO3, and 30 min of reaction time. Having particles size of 19 to 37 nm under optimized conditions, the AgNPs revealed a 82.3% degradation of methyl orange dye under UV light irradiation. The antibacterial response of the optimized AgNPs against S. aureus and E. coli strains revealed inhabitation zones of 15 mm and 12 mm, respectively, which demonstrate an antioxidant activity of 81.2%.
Hinged Adaptive Fiber-Rubber Composites Driven by Shape Memory Alloys—Development and Simulation
Authors: Lohse Felix , Annadata Achyuth Ram , Häntzsche Eric , Gereke Thomas , Trümper Wolfgang , Cherif Chokri
Published: May 2022

Adaptive structures based on fiber-rubber composites with integrated Shape Memory Alloys are promising candidates for active deformation tasks in the fields of soft robotics and human-machine interactions. Solid-body hinges improve the deformation behavior of such composite structures. Textile technology enables the user to develop reinforcement fabrics with tailored properties suited for hinged actuation mechanisms. In this work, flat knitting technology is used to create biaxially reinforced, multilayer knitted fabrics with hinge areas and integrated Shape Memory Alloy wires. The hinge areas are achieved by dividing the structures into sections and varying the configuration and number of reinforcement fibers from section to section. The fabrics are then infused with silicone, producing a fiber-rubber composite specimen. An existing simulation model is enhanced to account for the hinges present within the specimen. The active deformation behavior of the resulting structures is then tested experimentally, showing large deformations of the hinged specimens. Finally, the simulation results are compared to the experimental results, showing deformations deviating from the experiments due to the developmental stage of the specimens. Future work will benefit from the findings by improving the deformation behavior of the specimens and enabling further development for first applications.
Structural and Optical Characterization of Mechanochemically Synthesized CuSbS2 Compounds
Authors: Esperto Luís , Figueira Isabel , Mascarenhas João , Silva Teresa P. , Correia José B. , Neves Filipe
Published: May 2022

One of the areas of research on materials for thin-film solar cells focuses on replacing In and Ga with more earth-abundant elements. In that respect, chalcostibite (CuSbS2) is being considered as a promising environmentally friendly and cost-effective photovoltaic absorber material. In the present work, single CuSbS2 phase was synthesized directly by a short-duration (2 h) mechanochemical-synthesis step starting from mixtures of elemental powders. X-ray diffraction analysis of the synthesized CuSbS2 powders revealed a good agreement with the orthorhombic chalcostibite phase, space group Pnma, and a crystallite size of 26 nm. Particle-size characterization revealed a multimodal distribution with a median diameter ranging from of 2.93 μm to 3.10 μm. The thermal stability of the synthesized CuSbS2 powders was evaluated by thermogravimetry and differential thermal analysis. No phase change was observed by heat-treating the mechanochemically synthesized powders at 350 °C for 24 h. By UV-VIS-NIR spectroscopy the optical band gap was determined to be 1.41 eV, suggesting that the mechanochemically synthesized CuSbS2 can be considered suitable to be used as absorber materials. Overall, the results show that the mechanochemical process is a viable route for the synthesis of materials for photovoltaic applications.
Relationship between Structure and Antibacterial Activity of α-Aminophosphonate Derivatives Obtained via Lipase-Catalyzed Kabachnik−Fields Reaction
Authors: Koszelewski Dominik , Kowalczyk Paweł , Śmigielski Paweł , Samsonowicz-Górski Jan , Kramkowski Karol , Wypych Aleksandra , Szymczak Mateusz , Ostaszewski Ryszard
Published: May 2022

We reported a new method dealing with the synthesis of novel pharmacologically relevant α-aminophosphonate derivatives via a lipase-catalyzed Kabachnik−Fields reaction with yields of up to 93%. The advantages of this protocol are excellent yields, mild reaction conditions, low costs, and sustainability. The developed protocol is applicable to a range of H-phosphites and organic amines, providing a wide substrate scope. A new class of α-aminophosphonate analogues possessing P-chiral centers was also synthesized. The synthesized compounds were characterized on the basis of their antimicrobial activities against E. coli. The impact of the various alkoxy groups on antimicrobial activity was demonstrated. The crucial role of the substituents, located at the aromatic rings in the phenylethyloxy and benzyloxy groups, on the inhibitory action against selected pathogenic E. coli strains was revealed. The observed results are especially important because of increasing resistance of bacteria to various drugs and antibiotics.
Recent Progress in the Removal of Legacy and Emerging Organic Contaminants from Wastewater Using Metal–Organic Frameworks: An Overview on Adsorption and Catalysis Processes
Authors: Badea Silviu-Laurentiu , Niculescu Violeta-Carolina
Published: May 2022

Water covers about 70% of the Earth’s surface, but the amount of freshwater available for human use is only 2.5% and, although it is continuously replenished via the water cycle, freshwater is a finite and limited resource. The Earth’s water is affected by pollution and while water quality is an issue of global concern, the specific regulations on contaminants of emerging concern (CECs) are limited. In order to achieve the goals set by EU regulations, the treatment of wastewater is a scientifically and technologically challenging issue. Metal–organic frameworks (MOFs) are promising materials used for the removal of priority and emerging contaminants from wastewater, since they can mitigate those contaminants via both adsorption as well as catalysis processes. MOFs can offer selective adsorption of CECs by various adsorption mechanisms. The catalytic removal of priority and emerging organic contaminants from wastewater using MOFs implies Fenton, electro-Fenton, and photo-Fenton processes. Overall, MOFs can be considered as promising materials for the elimination of priority and emerging organic contaminants from various wastewater types, but the involved processes must be studied in detail for a larger number of compounds.
Sugar Palm Fibre-Reinforced Polymer Composites: Influence of Chemical Treatments on Its Mechanical Properties
Authors: Asyraf Muhammad Rizal Muhammad , Syamsir Agusril , Supian Abu Bakar Mohd , Usman Fathoni , Ilyas Rushdan Ahmad , Nurazzi Norizan Mohd , Norrrahim Mohd Nor Faiz , Razman Muhammad Rizal , Zakaria Sharifah Zarina Syed , Sharma Shubham , Itam Zarina , Rashid Mohamad Zakir Abd
Published: May 2022

In the era of globalisation, decreasing synthetic resources, especially petroleum, have encouraged global communities to apply biomass waste as a substitute material for green technology development. The development of plastic products from lignocellulosic fibre-reinforced composites has been a hot topic among material scientists and engineers due to their abundance, sustainable in nature, and less toxic towards health. For the Malaysian scenario, sugar palm is a plant found in the wild and locally planted in certain areas in Malaysia and Indonesia. Generally, sugar palm can be harvested for traditional foods, fruits, starch sugar (gula kabung), and alcohol, whereas sugar palm fibre (SPF) is used in conventional products (brushes and brooms). Various researchers are working on the characterisation of fibre and its composites for engineering and packaging products. The main drawback of SPF is its hydrophilic behaviour, which leads to high moisture uptake and inhibits a good bond between the fibre and the matrix. Thus, a solution for this problem is by implementing chemical treatments on the fibre. From the literature review, no comprehensive review paper has been published on the influence of chemical treatment on the mechanical behaviour of SPF-reinforced polymer composites. Thus, the present review examines recent studies on the mechanical properties of sugar palm lignocellulosic fibres with various chemical treatments to evaluate their potential in structural applications.
Numerical Investigation of Flow Force and Cavitation Phenomenon in the Pilot Stage of Electrical-Hydraulic Servo Valve under Temperature Shock
Authors: Ma Li , Yan Hao , Ren Yukai , Li Lei , Cai Cunkun
Published: May 2022

The flow field structure in the pilot stage of the electro-hydraulic servo valve is small and complex, and the extreme temperature environment will aggravate the self-excited oscillation, resulting in a decrease in the control accuracy of the servo valve. With the increase in temperature, the size of the orifice, the temperature characteristics of the fluid and the pressure loss in the flow pipe will influence the characteristics of the pilot stage. Considering the influence of temperature and pressure loss, a theoretical mathematical model is established to describe the flow force in the pilot stage. To verify the accuracy of the theoretical model, CFD simulations of the flow force at different inlet pressures and deflection positions and temperatures are analyzed in this paper. As the temperature rises, the oil viscosity rapidly decreases, which results in the flow force acting on the flapper increasing with the temperature. When the temperature exceeds 50 °C, the effect of oil viscosity is small, and the flow force tends to decrease slightly with the combined effect. As the supply oil pressure increases and the flapper moves toward the nozzle, the flow force acting on the flapper increases, and the trend is consistent with the CFD simulation results. An experimental device is designed, including establishing the experimental conditions and measuring the flow force to validate the theoretical model and to observe the cavitation phenomenon of the pilot stage.
A Compound Control Method Based on the Adaptive Linear Extended State Observer and Global Fast Terminal Sliding Mode Control for Inertially Stabilized Platform
Authors: Fu Fa , Lei Xusheng , Wang Rui
Published: May 2022

To realize high-performance control for the inertially stabilized platform, a compound control method based on the adaptive linear extended state observer and global fast terminal sliding mode control is proposed. For estimating the unknown disturbances of inertially stabilized platform, an adaptive linear extended state observer was developed. With the full use of the information of attitude and angular velocity, the adaptive bandwidth of an adaptive linear extended state observer can deal with the peaking phenomenon without introducing excessive noise. Furthermore, the adaptation law based on the global fast terminal sliding mode control for disturbance estimation compensation was developed, which can improve the disturbance estimation accuracy of the adaptive linear extended state observer, and the higher order terminal function in global fast terminal sliding mode control was replaced by the lumped disturbance estimation of adaptive linear extended state observer, which can improve the anti-interference ability of inertially stabilized platform, reduce the chattering problem, and improve the control performance. The asymptotic stability of the proposed control method has been proven by the Lyapunov stability theory. The effectiveness of the proposed method was validated by a series of simulations and experiments.
Existence of Solutions for Coupled Higher-Order Fractional Integro-Differential Equations with Nonlocal Integral and Multi-Point Boundary Conditions Depending on Lower-Order Fractional Derivatives and Integrals
Authors: Subramanian Muthaiah , Alzabut Jehad , Abbas Mohamed I. , Thaiprayoon Chatthai , Sudsutad Weerawat
Published: May 2022

In this article, we investigate the existence and uniqueness of solutions for a nonlinear coupled system of Liouville–Caputo type fractional integro-differential equations supplemented with non-local discrete and integral boundary conditions. The nonlinearity relies both on the unknown functions and their fractional derivatives and integrals in the lower order. The consequence of existence is obtained utilizing the alternative of Leray–Schauder, while the result of uniqueness is based on the concept of Banach contraction mapping. We introduced the concept of unification in the present work with varying parameters of the multi-point and classical integral boundary conditions. With the help of examples, the main results are well demonstrated.
Topological Data Analysis with Spherical Fuzzy Soft AHP-TOPSIS for Environmental Mitigation System
Authors: Riaz Muhammad , Tanveer Shaista , Pamucar Dragan , Qin Dong-Sheng
Published: May 2022

The idea of spherical fuzzy soft set (SFSS) is a new hybrid model of a soft set (SS) and spherical fuzzy set (SFS). An SFSS is a new approach for information analysis and information fusion, and fuzzy modeling. We define the concepts of spherical-fuzzy-soft-set topology (SFSS-topology) and spherical-fuzzy-soft-set separation axioms. Several characteristics of SFSS-topology are investigated and related results are derived. We developed an extended choice value method (CVM) and the AHP-TOPSIS (analytical hierarchy process and technique for the order preference by similarity to ideal solution) for SFSSs, and presented their applications in multiple-criteria group decision making (MCGDM). Moreover, an application of the CVM is presented in a stock market investment problem and another application of the AHP-TOPSIS is presented for an environmental mitigation system. The suggested methods are efficiently applied to investigate MCGDM through case studies.
Magneto Mixed Convection of Williamson Nanofluid Flow through a Double Stratified Porous Medium in Attendance of Activation Energy
Authors: Tamilzharasan B. M. , Karthikeyan S. , Kaabar Mohammed K. A. , Yavuz Mehmet , Özköse Fatma
Published: May 2022

This article aims to develop a mathematical simulation of the steady mixed convective Darcy–Forchheimer flow of Williamson nanofluid over a linear stretchable surface. In addition, the effects of Cattaneo–Christov heat and mass flux, Brownian motion, activation energy, and thermophoresis are also studied. The novel aspect of this study is that it incorporates thermal radiation to investigate the physical effects of thermal and solutal stratification on mixed convection flow and heat transfer. First, the profiles of velocity and energy equations were transformed toward the ordinary differential equation using the appropriate similarity transformation. Then, the system of equations was modified by first-order ODEs in MATLAB and solved using the bvp4c approach. Graphs and tables imply the impact of physical parameters on concentration, temperature, velocity, skin friction coefficient, mass, and heat transfer rate. The outcomes show that the nanofluid temperature and concentration are reduced with the more significant thermal and mass stratification parameters estimation.
Marine Microbial-Derived Resource Exploration: Uncovering the Hidden Potential of Marine Carotenoids
Authors: Steven Ray , Humaira Zalfa , Natanael Yosua , Dwivany Fenny M. , Trinugroho Joko P. , Dwijayanti Ari , Kristianti Tati , Tallei Trina Ekawati , Emran Talha Bin , Jeon Heewon , Alhumaydhi Fahad A. , Radjasa Ocky Karna , Kim Bonglee
Published: May 2022

Microbes in marine ecosystems are known to produce secondary metabolites. One of which are carotenoids, which have numerous industrial applications, hence their demand will continue to grow. This review highlights the recent research on natural carotenoids produced by marine microorganisms. We discuss the most recent screening approaches for discovering carotenoids, using in vitro methods such as culture-dependent and culture-independent screening, as well as in silico methods, using secondary metabolite Biosynthetic Gene Clusters (smBGCs), which involves the use of various rule-based and machine-learning-based bioinformatics tools. Following that, various carotenoids are addressed, along with their biological activities and metabolic processes involved in carotenoids biosynthesis. Finally, we cover the application of carotenoids in health and pharmaceutical industries, current carotenoids production system, and potential use of synthetic biology in carotenoids production.
Antimicrobial and Immunoregulatory Activities of TS40, a Derived Peptide of a TFPI-2 Homologue from Black Rockfish (Sebastes schlegelii)
Authors: Liu Hongmei , Wang Guanghua , Hao Dongfang , Wang Changbiao , Zhang Min
Published: May 2022

Tissue factor pathway inhibitor-2 (TFPI-2) is a Kunitz-type serine protease inhibitor. Previous reports have shown that TFPI-2 plays an important role in innate immunity, and the C-terminal region of TFPI-2 proved to be active against a broad-spectrum of microorganisms. In this study, the TFPI-2 homologue (SsTFPI-2) of black rockfish (Sebastods schegelii) was analyzed and characterized, and the biological functions of its C-terminal derived peptide TS40 (FVSRQSCMDVCAKGAKQHTSRGNVRRARRNRKNRITYLQA, corresponding to the amino acid sequence of 187-226) was investigated. The qRT-PCR (quantitative real-time reverse transcription-PCR) analysis showed that the expression of SsTFPI-2 was higher in the spleen and liver. The expression of SsTFPI-2 increased significantly under the stimulation of Listonella anguillarum. TS40 had a strong bactericidal effect on L. anguillarum and Staphylococcus aureus. Further studies found that TS40 can destroy the cell structure and enter the cytoplasm to interact with nucleic acids to exert its antibacterial activity. The in vivo study showed that TS40 treatment could significantly reduce the transmission of L. anguillarum and the viral evasion in fish. Finally, TS40 enhanced the respiratory burst ability, reactive oxygen species production and the expression of immune-related genes in macrophages, as well as promoted the proliferation of peripheral blood leukocytes. These results provide new insights into the role of teleost TFPI-2.
Antihypertensive Effects of IGTGIPGIW Peptide Purified from Hippocampus abdominalis: p-eNOS and p-AKT Stimulation in EA.hy926 Cells and Lowering of Blood Pressure in SHR Model
Authors: Lee Hyo-Geun , Kim Hyun-Soo , An Hyesuck , Baek Kyunghwa , Lee Jeong Min , Yim Mi-Jin , Ko Seok-Chun , Kim Ji-Yul , Oh Gun-Woo , Je Jun-Geon , Lee Dae-Sung , Jeon You-Jin
Published: May 2022

The aim of this study was to assess the potential hypertensive effects of the IGTGIPGIW peptide purified from Hippocampus abdominalis alcalase hydrolysate (HA) for application in the functional food industry. We investigated the antihypertensive effects of IGTGIPGIW in vitro by assessing nitric oxide production in EA.hy926 endothelial cells, which is a major factor affecting vasorelaxation. The potential vasorelaxation effect was evaluated using 4-amino-5-methylamino-2′,7′-difluorofluorescein diacetate, a fluorescent stain. IGTGIPGIW significantly increased the expression of endothelial-derived relaxing factors, including endothelial nitric oxide synthase and protein kinase B, in EA.hy926 cells. Furthermore, oral administration of IGTGIPGIW significantly lowered the systolic blood pressure (183.60 ± 1.34 mmHg) and rapidly recovered the diastolic blood pressure (143.50 ± 5.55 mmHg) in the spontaneously hypertensive rat model in vivo. Our results demonstrate the antihypertensive activity of the IGTGIPGIW peptide purified from H. abdominalis and indicate its suitability for application in the functional food industry.
Therapeutic Potential of Phlorotannin-Rich Ecklonia cava Extract on Methylglyoxal-Induced Diabetic Nephropathy in In Vitro Model
Authors: Cho Chi-Heung , Lee Chang-Jun , Kim Min-Gyeong , Ryu Bomi , Je Jun-Geon , Kim Yoonsook , Lee Sang-Hoon
Published: May 2022

Advanced glycation end-products (AGEs) play a vital role in the pathogenesis of diabetic complications. Methylglyoxal (MGO), one of the major precursors of AGEs, is a highly reactive dicarbonyl compound that plays an important role in the pathogenesis of diabetic nephropathy. This study was designed to evaluate the therapeutic potential of phlorotannin-rich Ecklonia cava extract (ECE) on MGO-induced diabetic nephropathy in in vitro models using mouse glomerular mesangial cells. ECE showed anti-glycation activity via breaking of AGEs-collagen cross-links and inhibition of AGEs formation and AGE-collagen cross-linking formation. The renoprotective effects were determined by assessing intracellular reactive oxygen species (ROS) and MGO accumulation, cell apoptosis, and the Nrf-2/ARE signaling pathway. MGO-induced renal damage, intracellular ROS production level, and MGO-protein adduct accumulation were significantly decreased by pretreating ECE. Moreover, ECE pretreatment exhibited preventive properties against MGO-induced dicarbonyl stress via activation of the Nrf2/ARE signaling pathway and reduction of RAGE protein expression in mouse glomerular mesangial cells. Collectively, these results indicated potential anti-glycation properties and prominent preventive effects of ECE against MGO-induced renal damage. Additionally, ECE may be utilized for the management of AGE-related diabetic nephropathy.
A Novel Bi-Functional Fibrinolytic Enzyme with Anticoagulant and Thrombolytic Activities from a Marine-Derived Fungus Aspergillus versicolor ZLH-1
Authors: Zhao Lihong , Lin Xiuping , Fu Jingyun , Zhang Jun , Tang Wei , He Zengguo
Published: May 2022

Fibrinolytic enzymes are important components in the treatment of thrombosis-associated disorders. A new bi-functional fibrinolytic enzyme, versiase, was identified from a marine-derived fungus Aspergillus versicolor ZLH-1. The enzyme was isolated from the fungal culture through precipitation with ammonium sulfate at 90% saturation. Additionally, it was further purified by DEAE-based ion-exchange chromatography, with a recovery of 20.4%. The fibrinolytic enzyme presented as one band on both SDS-PAGE and fibrin-zymogram, with a molecular mass of 37.3 kDa. It was elucidated as a member of metalloprotease in M35 family by proteomic approaches. The homology-modeling analysis revealed that versiase shares significant structural homology wuth the zinc metalloendopeptidase. The enzyme displayed maximum activity at 40 °C and pH 5.0. The activity of versiase was strongly inhibited by the metalloprotease inhibitors EDTA and BGTA. Furthermore, versiase hydrolyzed fibrin directly and indirectly via the activation of plasminogen, and it was able to hydrolyze the three chains (α, β, γ) of fibrin(ogen). Additionally, versiase demonstrated promising thrombolytic and anticoagulant activities, without many side-effects noticed. In conclusion, versiase appears to be a potent fibrinolytic enzyme deserving further investigation.
Polyene Macrolactams from Marine and Terrestrial Sources: Structure, Production Strategies, Biosynthesis and Bioactivities
Authors: Zhao Wei , Jiang Hong , Liu Xiao-Wan , Zhou Jian , Wu Bin
Published: May 2022

Over the past few decades (covering 1972 to 2022), astounding progress has been made in the elucidation of structures, bioactivities and biosynthesis of polyene macrolactams (PMLs), but they have only been partially summarized. PMLs possess a wide range of biological activities, particularly distinctive fungal inhibitory abilities, which render them a promising drug candidate. Moreover, the unique biosynthetic pathways including β-amino acid initiation and pericyclic reactions were presented in PMLs, leading to more attention from inside and outside the natural products community. According to current summation, in this review, the chem- and bio-diversity of PMLs from marine and terrestrial sources are considerably rich. A systematic, critical and comprehensive overview is in great need. This review described the PMLs’ general structural features, production strategies, biosynthetic pathways and the mechanisms of bioactivities. The challenges and opportunities for the research of PMLs are also discussed.
Diagnostic Value of Radioisotope Cisternography Using 111In-DTPA in a Patient with Rhinorrhea and Purulent Meningitis
Authors: Porubcin Stefan , Rovnakova Alena , Zahornacky Ondrej , Jarcuska Pavol
Published: May 2022

Cerebrospinal fluid (CSF) leakage is a rare condition. Prompt diagnosis and early treatment of CSF leakage minimizes the risk of severe complications such as bacterial meningitis. Different diagnostic modalities are used to detect the site of CSF leakage but often with unreliable results. The literature offers limited evidence-based guidance on the diagnostic approach for rhinorrhea. Correct localization of the defect is the mainstay for successful surgical treatment. Herein, we describe a case of recurrent meningitis due to cranio-nasal fistula and rhinorrhea successfully localized with radioisotope cisternography (RIC). We provide a detailed and practical overview of the RIC procedure and compare different imaging modalities used to detect the site of CSF leakage.
The Association of Minimally Invasive Surgical Approaches and Mortality in Patients with Malignant Pleuropericarditis—A 10 Year Retrospective Observational Study
Authors: Nistor Claudiu-Eduard , Găvan Camelia Stanciu , Ciritel Alexandra-Andreea , Nemes Alexandra Floriana , Ciuche Adrian
Published: May 2022

Background and Objectives: Malignant neoplasms are common causes of acute pleuropericardial effusion. Pleuropericarditis denotes poor patient prognosis, is associated with shortened average survival time, and represents a surgical emergency. Materials and Methods: We analyzed the impact of two minimally invasive surgical approaches, the type of cancer, and other clinical variables on the mortality of 338 patients with pleuropericarditis admitted to an emergency hospital in Romania between 2009 and 2020. All patients underwent minimally invasive surgeries to prevent the recurrence of the disease and to increase their life expectancy. Log-rank tests were used to check for survival probability differences by surgical approach. We also applied univariate and multivariate Cox proportional hazard models to assess the effect of each covariate. Results: No significant differences were found in the 2-year overall survival rate between patients who underwent the two types of surgery. The multivariate Cox proportional regression model adjusted for relevant covariates showed that age, having lung cancer, and a diagnosis of pericarditis and right pleural effusion increased the mortality risk. The surgical approach was not associated with mortality in these patients. Conclusion: These findings open up avenues for future research to advance the understanding of survival among patients with pleuropericarditis.
Influence of Visible Violet, Blue and Red Light on the Development of Cataract in Porcine Lenses
Authors: Zeller Katja , Mühleisen Stephan , Shanmugarajah Pranavi , Fehler Nicole , Haag Robin , Hessling Martin
Published: May 2022

Background and Objectives: Cataract is a disease that is globally prevalent in today’s population and occurs mostly in the elderly. It is an opacity of the lens that worsens vision and can lead to blindness. One well-known risk factor of cataract is ultraviolet (UV) radiation. However, increasing exposure to modern artificial light sources like light emitting diodes (LEDs) and displays might have an impact on cataract formation due to possible high (and hidden) blue radiation. An ex-vivo study indicates that intense blue radiation causes cataract in porcine lenses. The goal of this work is the investigation whether violet or red light also lead to cataract formation in porcine lenses and to compare the impact of the different wavelengths. Materials and Methods: LEDs with wavelengths of 407 nm (violet), 463 nm (blue) and 635 nm (red) are used to irradiate ex–vivo porcine lenses with a dose of 6 kJ/cm2. Before and after irradiation the lens transmissions are measured and dark field images are taken to determine cataract formation. The same procedure is performed for unirradiated controls. Results: The results of the transmission measurements are in accordance with the results of the dark field images and state that 635 nm (red) is inducing no or only weak cataract. In comparison to the dark field images the transmission measurements exhibit stronger cataract formation for 407 nm than for 463 nm irradiation while the dark field images show similar cataract formation for both wavelengths. Conclusions: Visible light of short wavelengths cause cataract formation in porcine eyes, and it cannot be excluded that these wavelengths, which are emitted by modern LED illuminants, also pose a danger to human eyes.