bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical and thermal properties of flax/carbon/kevlar based epoxy hybrid composites
Authors: T. G. Yashas Gowda , A. Vinod , P. Madhu , Mavinkere Rangappa Sanjay , Siengchin Suchart , Jawaid Mohammad 
Published: July 2022

AbstractIn recent years, awareness on environmental issues has led to development of biobased materials for a variety of engineering structural applications. Nowadays, researchers and scientists are focusing their efforts on the development of sustainable materials that make use of readily available, renewable, and biodegradable natural resources. While significant progress has been made in the study of hybrid fiber reinforced composites, the fundamental problem of incorporating and selecting the optimal combination of reinforced fibers for various applications has not been adequately addressed. Hence present study addresses the use of combination of two natural fibers with different synthetic fibers to assess the performance of the hybrid fibers composites to develop for engineering applications. In present work the effect of stacking sequence on the mechanical and thermal property of the flax, kevlar, carbon and carbon‐kevlar hybrid fiber reinforced epoxy composites are studied. The four layered composite laminates with different stacking sequence were fabricated using hand layup technique to study the mechanical properties such as tensile, flexural, interlaminar shear, and impact tests, thermal behavior, water absorption, contact angle measurement and scanning electron microscopy. The hybrid carbon/flax composite (CFFC) had better strength as compared to KFFC, HFFC, and FFFF composite laminates with better tensile strength (178.48 MPa), tensile modulus (2132 MPa), flexural strength (378.86 MPa), flexural modulus (15.76 GPa) and interlaminar shear strength (13.91 MPa) and impact strength (13.86 MPa) and water absorption behavior. The stacking sequence revealed that the hybridization of the flax with the synthetic fiber enhanced the properties as compared to the pure flax composites. The influence of the synthetic fibers at outer skin layer had the effect on enhancing the properties of composites. From the obtained results we can effectively utilize the hybrid flax fibers in some various lightweight engineering applications.
Plasma methane activation on mesoporous silica for energy efficiency improvement
Authors: Park Kilsu , Park Daeil , Kim Taegyu 
Published: July 2022

AbstractThis study describes plasma CH4 activation on mesoporous silica (SBA‐15) with a high specific surface area (SSA) for energy efficiency improvement. A dielectric barrier discharge plasma was used, and the SSA of SBA‐15 was varied by controlling the hydrothermal reaction (HR) temperature. The effect of the SSA was investigated to improve the plasma CH4 activation. The synthesized SBA‐15 had a well‐ordered two‐dimensional hexagonal structure. CH4 conversion and C2 selectivity using plasma catalysis were twice as high as those using only the catalyst, because vibrationally excited CH4 can be adsorbed with low activation energy. Additionally, the energy efficiency was higher than that of other plasma catalysts when the plasma was applied to mesoporous SBA‐15 with the SSA of 516 m2 g−1 at a discharge frequency of 0.1 kHz.
Strain Rate and Temperature Effects of the JOXL‐1 Explosive
Authors: Zhu Xintao , Zhang Xiaojing , Li Wenbin , Yao Wenjin 
Published: July 2022

AbstractTo determine the influence of temperature and strain rate on the mechanical behavior of JOXL‐1 explosive, the stress‐strain curves of JOXL‐1 explosive at different temperatures (233 K‐473 K) and different strain rates (110 s−1‐400 s−1) were measured using a split Hopkinson pressure bar (SHPB) experimental system with a temperature control device. The results show that the dynamic mechanical properties of this explosive are sensitive to the strain rate and temperature in the experimental temperature range. The failure stress increases with increasing strain rate and decreases with increasing temperature. The failure strain increases with increasing strain rate, but it is almost unaffected by temperature. The DSC analysis shows that the JOXL‐1 explosive has good thermal stability when the temperature is lower than 391.37 K and that binders in the explosive gradually decompose when the temperature is higher than 391.37 K.
Experimental measurement and theoretical prediction for lower flammability limits of ternary hydrocarbon mixtures
Authors: Qi Chang , He Meng , Ning Ye , Chen Sheng , Yan Xingqing , Wang Yalei , Yu Xiaozhe , Yu Jianliang 
Published: July 2022

AbstractThe present work experimentally investigated the lower flammability limits of methane‐ethylene‐propane‐air mixtures at ambient temperature and pressure in a 20 L confined chamber. Moreover, a calculated flame temperature (CFT) modeling for predicting the lower flammability limit of multicomponent mixed combustible gas was proposed based on the law of conservation of energy. The results indicated that the relative error of Le Chatelier's law is 2.88% in the prediction of the lower flammability limit of the tested multicomponent mixed combustible medium. Also, the relative error of CFT modeling is only 1.47%, which is reduced by 48.96% and can significantly improve the prediction accuracy of the lower flammability limit of multicomponent mixtures. Furthermore, using the premixed laminar flame speed reactor, the USC 2.0 mechanism was employed to obtain the behavior of ternary hydrocarbon mixtures near the flammability limits. The sensitivity analysis showed that competition between the chain branching reaction R1 (H + O2 ⟺ O + OH) and the chain termination reaction R12 (H + CH3(+M) ⟺ CH4(+M)) was crucial in determining the lower flammable limit.
Tanshinone IIA improves contextual fear‐ and anxiety‐like behaviors in mice via the CREB/BDNF/TrkB signaling pathway
Authors: Jiang Yong‐li , Wang Xin‐shang , Li Xu‐bo , Liu An , Fan Qing‐yu , Yang Le , Feng Ban , Zhang Kun , Lu Liang , Qi Jing‐yu , Yang Fan , Song Da‐ke , Wu Yu‐mei , Zhao Ming‐gao , Liu Shui‐bing 
Published: July 2022

AbstractPosttraumatic stress disorder (PTSD) is one of the most common psychiatric diseases, which is characterized by the typical symptoms such as re‐experience, avoidance, and hyperarousal. However, there are few drugs for PTSD treatment. In this study, conditioned fear and single‐prolonged stress were employed to establish PTSD mouse model, and we investigated the effects of Tanshinone IIA (TanIIA), a natural product isolated from traditional Chinese herbal Salvia miltiorrhiza, as well as the underlying mechanisms in mice. The results showed that the double stress exposure induced obvious PTSD‐like symptoms, and TanIIA administration significantly decreased freezing time in contextual fear test and relieved anxiety‐like behavior in open field and elevated plus maze tests. Moreover, TanIIA increased the spine density and upregulated synaptic plasticity‐related proteins as well as activated CREB/BDNF/TrkB signaling pathway in the hippocampus. Blockage of CREB remarkably abolished the effects of TanIIA in PTSD model mice and reversed the upregulations of p‐CREB, BDNF, TrkB, and synaptic plasticity‐related protein induced by TanIIA. The molecular docking simulation indicated that TanIIA could interact with the CREB‐binding protein. These findings indicate that TanIIA ameliorates PTSD‐like behaviors in mice by activating the CREB/BDNF/TrkB pathway, which provides a basis for PTSD treatment.
Learning to become ignorant: Improving the quality of epistemic knowledge in science education
Authors: Tan Michael , Koh Teck Seng 
Published: July 2022

AbstractIn considering goals for science education, it is conventional to make arguments for the utility of scientific knowledge for a variety of purposes. Less prominent are rationales based on the beauty or truth of science. In this paper, we examine how an approach to science education might be different if we shift the goals of communication to an appreciation of the ways in which our knowledge is limited, and how the practical boundaries of our knowledge can be closer than we think—in other words, how we are collectively ignorant. Key to this approach is a renewed understanding of the role of material investigations in providing partial knowledge. Instead of providing incontrovertible evidence, empirical investigations provide a form of “explanatory excess” whereby the appropriate choice of explanation is not necessarily one that can be simplistically determined. Although scientific practices provide techniques to minimize the possibility of error in making our conclusions, these practices are performed by fallible human communities, from which the notion of “tentative, yet durable” claims derives. We argue that public scientific literacy may be better served by more circumspect claims of validity, and crucially, an enhanced understanding of the ways in which materiality influences epistemic processes and limits our claims. We illustrate these proposals through the case of the International Young Physicists' Tournament, a contest that invites participants to play with interesting physical phenomena for over a year. We identify three factors prominent in these tournament problems that present possibilities for increasing the authenticity of practical investigations. These are (i) multiple physical interactions in phenomena leading to the openness of choice of explanatory theory; (ii) the qualitative, subjective nature of the explanatory utility of theories; and (iii) the material contingency of empirical investigations. We argue that a more open‐handed embrace of the limits of our knowledge may serve as a better epistemic orientation for science instruction.
Substituent Effect: Synthesis of Three TNP‐Detecting Fluorescent Probes Based on Triazolothiadiazole‐Quinazolinone**
Authors: Zhang Chenglu , Wang Yiming , Jiang Yanhua , Zhang Yining , Xie Yanxuan , Gong Rongqing , Hao Qiang 
Published: July 2022

AbstractThree novel fluorescent probes (QZLSZ‐1∼QZLSZ‐3) were designed and synthesized based on quinazolinone for comparing the representative substituent effects on QZLSZ fluorescence detection of 2, 4, 6‐trinitrophenol (TNP). The results show that the probes all exhibit high selectivity and good photo‐stability in wide pH rang and high quenching efficiency, indicating the rational structural design. Compared the substituent effects on the fluorescent properties of QZLSZ, it is found that electron ‐ donating group in QZLSZ‐1 is more favorable than the electron‐withdrawing group in QZLSZ‐3. The probe QZLSZ‐1 has the highest fluorescence quantum yield (0.5407) and the biggest Storks shift (191 nm). Furthermore, it has the lowest detection limit (0.16 μM), the optimal sensitivity (1.3 × 105 M−1), the largest detection range (10∼50 μM) and the rapidest response time (60 s) for the fluorescence recognition of TNP. The theoretical calculation results using Density functional theory (DFT) are highly consistent with that of the experiments. Particularly, QZLSZ‐1 has the best practical application value for qualitative and quantitative fluorescence detection of TNP in actual water samples.
Synthesis and Characterization of Zinc Oxide Nanoparticles Using Thermophilic Bacteria Isolated from Arid Region of Rajasthan
Authors: Parihar Jagdish , Kumawat Ashok , Misra Kamakhya Prakash , Bagaria Ashima 
Published: July 2022

AbstractFour bacterial strains were used for biosynthesis of zinc oxide (ZnO) nanoparticles (NPs), namely Bacillus tropicus SHJP5, Bacillus tropicus LKJP6, Aeribacillus composti SJP25, and Aeribacillus pallidus SJP28. The synthesized nanoparticles were characterized using UV‐Visible spectroscopy (UV‐Vis), Fourier transform infrared spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Photoluminescence spectroscopy (PL), Thermogravimetric analysis (TGA), and X‐ray diffraction (XRD). The XRD pattern of NPs (bio‐synthesized) shows the polycrystalline hexagonal wurtzite structure with the three major planes (100), (002), and (001). The average crystallite size determined by the Debye‐Scherrer equation is between 8–54 nm. A reduction in crystallite size of as‐prepared nanoparticles was observed in the presence of bacterial strains. The FTIR analysis reveals the amide, carboxyl, and hydroxyl groups found on the surface of biosynthesized ZnO NPs. These groups behave as reducing and stabilizing agents. The UV‐Vis spectra reveal the absorption bands for control, SHJP5, LKJP6, SJP25, and SJP28 at 373, 363, 382, 358, and 380 nm respectively. The corresponding energy band gap was found to be 3.324, 3.415, 3.246, 3.463, and 3.263 eV respectively, with the decreasing size of the nanoparticles produced by bacterial strains. The FESEM analysis confirms the hexagonal structure of bio‐synthesized ZnO NPs. The nanoparticles have a uniform distribution of spherical shape except for the strain Aeribacillus pallidus LKJP6 which exhibits uniform and thin nanorods. Minimum inhibitory concentration (MIC) tests against E. coli (7.1 mg/ml) and S. aureus (3.2 mg/ml) verified the antibacterial activity of produced ZnO NPs. The use of isolated strains for the extracellular manufacture of ZnO NPs is encouraged in this work. To the best of our knowledge, this might be the first study that has been presented that shows the structural, optical, and surface morphology of a thermophilic bacterium, Bacillus tropicus SHJP5, Bacillus tropicus LKJP6, Aeribacillus composti SJP25, and Aeribacillus pallidus SJP28 for the biosynthesis of ZnO NPs in particular.
Photocatalyzed gem‐Difluoroallylation of Tertiary Amines with α‐Trifluoromethyl Alkenes
Authors: Yang Chunhui , Chen Jingchao , Li Xinhan , Yang Xiaoju , Zhu Yuanbin , Wu Shiyuan , Zeng Guangzhi , Wang Kaimin , Fan Baomin 
Published: July 2022

AbstractThe gem‐difluoroalkene moiety has attracted considerable attention from the synthetic chemistry community due to its outstanding performance in the drug design and development. By employing 4‐CzIPN as photocatalyst, a metal‐free synthetic method for gem‐difluoroalkenes is developed under blue LED irradiation. A wide range of tertiary amines and α‐trifluoromethyl alkenes are applicable in the present gem‐difluoroallylation and successfully transformed into the gem‐difluoroalkenes in good yields.
Sustainable Efficient Synthesis of Pyrrolidones from Levulinic Acid over Pd/C Catalyst
Authors: Liu Yingxin , Wang Yun , Cheng Yuran , Wei Zuojun 
Published: July 2022

AbstractThe synthesis of 5‐methyl‐2‐pyrrolidone through reductive amination of levulinic acid (LA) with ammonium formate (AF) as a source of both hydrogen and nitrogen over Pd/C catalyst was investigated. The effects of various reaction parameters, such as solvent, catalyst dosage, ammonium formate amount and temperature on the conversion of LA into 5‐methyl‐2‐pyrrolidone (MPD) were systematically investigated. The results showed that a MPD yield as high as 98 % was obtained in water at 180 °C for 4 h under a low metal content (0.28 mol% Pd relative to LA), which is higher than many previous reports. The Pd/C catalyst could be reused for at least 9 times with only a slight loss in activity. Meanwhile, Pd/C catalyst was efficient for the conversion of LA/ester into various N‐substituted‐5‐methyl‐2‐pyrrolidones (80–93 % yield) by using a mixture of formic acid and the corresponding primary amines.
PVC Coated Lignin/silica Composites Derived from Biomass Rice Husks as a High Performance Anode Material for Lithium Ion Batteries
Authors: Cui Xinying , Liu Li , Liu Xiaoyang , Li Yixin , He Zhongyu , Liu Liangyu , Zhang Minzhe , Zhu Yanchao , Wang Xiaofeng 
Published: July 2022

AbstractLignin, as the second most abundant natural polymer, has not been fully utilized in the industrial field due to the complex structure and functional groups. In this paper, polyvinyl chloride (PVC) coated lignin‐silica composites (PLS) with excellent cycling performance are prepared from rice husk and PVC through the method of alkali extraction and acid precipitation and mechanical mixing process. Due to the existence of functional groups on the surface of lignin, it can be closely combined with PVC to form a stable structure. The first discharge specific capacity and Coulombic efficiency of PLS is 1436 mA h g−1 and 56 %, respectively, and the reversible capacity is 720 mA h g−1 after 200 cycles at 0.1 A g−1, showing a stable cycling performance. This work promotes the application of lignin in the SiO2/C anode material of lithium ion battery, and confirms the stable combination between PVC and organic carbon.
An efficient approach to access 2,5‐disubstituted 1,3,4‐oxadiazoles by oxidation of 2‐arenoxybenzaldehyde N‐acyl hydrazones with molecular iodine
Authors: Başpınar Küçük Hatice , Alhonaish Anoud , Yıldız Tülay , Güzel Mustafa 
Published: July 2022

AbstractAn oxidative cyclization of 2‐arenoxybenzaldehyde N‐acyl hydrazones 3 a–o was employed to synthesize new 2,5‐disubstituted 1,3,4‐oxadiazole compounds 4 a–d, 4 f–i, 4 k–n. This method involves oxidative cyclization of 2‐arenoxybenzaldehyde N‐acyl hydrazones 3 a–o with molecular iodine mediated catalysis in which potassium carbonate served as a base. Characterization of all the synthesized novel compounds involved, proton and carbon NMR, mass spectrometry, and CHN elemental analysis. The synthesis of novel 2,5‐disubstituted 1,3,4‐oxadiazoles may display potential to provide pharmacologically important heterocyclic compounds.
Large‐Scale Synthesis of FeNi Nanoalloys‐Layered Porous N‐Doped Carbon Nanosheets for Efficient Electrocatalytic Water Splitting
Authors: Han Meng , Yun Yapei , Yao Aimin , Hu Jiashen , Wang Yan , Zhu Qingtao , Sheng Hongting , Du Yuanxin , Zhu Manzhou 
Published: July 2022

AbstractDeveloping non‐noble metal catalysts with high efficiency and stability is critical for the industrial application of electrocatalytic water splitting. Herein, FeNi nanoalloys‐layered porous N‐doped carbon nanosheets (FeNi‐NCS) were large‐scale synthesized by simple formamide pyrolysis method. The framework of FeNi‐NCS was a micro‐flowerlike structure composed of mesoporous N‐doped carbon nanosheets as petals, on which FeNi nanoalloy particles were uniformly dispersed. Benefiting from the unique N doping electronic modification, hierarchically porous structure, and the synergetic effect between Fe and Ni, the FeNi‐NCS exhibited high intrinsic activity and robust structure which can improve catalytic performance significantly. By tuning the pyrolysis temperature and the molar ratio of Fe and Ni, the Fe1Ni1‐NCS‐900 displayed optimal activity and stability for electrocatalytic hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) and required 261 and 310 mV overpotential to achieve 10 mA cm−2 respectively. This work presented a simple and effective way to fabricate high‐performance and stable non‐noble metal electrocatalysts for water splitting.
Fe3C Decorated N, Fe Co‐Doped Hollow Carbon Microspheres as Efficient Air Electrode Catalyst for Zinc‐Air Battery
Authors: Zhang Xiangtai , Hu Shuozhen , Sun Shigang , Zhang Xinsheng 
Published: July 2022

AbstractEfficient metal‐air batteries need active catalysts with low cost for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, hollow spherical Fe−M/G/H catalyst was synthesized through a polycondensation/pyrolysis method without template. Polycondensation of melamine, d‐glucose, and hexamethylenetetramine was accomplished to obtain carbon spheres with high nitrogen content. Hollow microspheres containing Fe‐Nx and Fe3C were fabricated by subsequent pyrolysis with Fe catalysts. Hollow microsphere structures not only expose more active sites (doped‐N, Fe‐Nx, and Fe3C), but also promote the mass transfer of O2. Fe−M/G/H possesses superior ORR performance in alkaline media with high limiting current density (5.09 mA cm−2) and half‐wave potential (0.80 V). The OER activity of Fe−M/G/H is superior to commercial Pt/C. Fe−M/G/H assembled zinc‐air battery exhibits high peak power density (90.27 mW cm−2) and long stability. This research provides a new approach to design hollow carbon catalysts with homo‐dispersed Fe‐Nx/Fe3C active sites and high doped‐N concentration.
One‐pot Economic Synthesis to the Functional Copper Mixed‐triazolate MOF Materials Towards an Enhanced Adsorptive Removal of Diclofenac Sodium
Authors: Chen Tianying , Shi Si , Yang Guang , Chen Zhihao , Zhang Wenhua 
Published: July 2022

AbstractFunctional copper mixed‐triazolate MOF materials (CuMtz‐3a and CuMtz‐3b), were designed and successfully prepared via simply stirring 1,2,4‐triazole (tzH) and the starting reactants of CuTz‐1 at room temperature. The obtained CuMtz‐3a and CuMtz‐3b were thoroughly characterized by PXRD, 1H‐NMR, EA, SEM, TG, etc. Furthermore, they were evaluated on the removal of diclofenac sodium (DCF). It was found that CuMtz‐3b, with a tzH doping of 18 %, exhibited a superior activity on the adsorption of DCF in the aqueous solution in comparison to that observed over CuMtz‐3a (10 % doping of tzH) and CuTz‐1. DCF adsorption over CuMtz‐3b are attributed to both anion exchange and hydrogen bonding. Owing to the incorporation of tzH, higher pore width and exposed hydrogen bonding sites (nitrogen sites of tzH) generated in CuMtz‐3b can improve the activity towards the removal of DCF. Furthermore, the regenerated CuMtz‐3b can be used for another three cycles while maintaining its crystallinity and morphology.
Indole‐2‐carboxamides as New Anti‐Mycobacterial Agents: Design, Synthesis, Biological Evaluation and Molecular Modeling against mmpL3
Authors: Bhakhar Kaushikkumar A. , Vaghela Punit V. , Varakala Saiprasad D. , Chudasma Shrdhhaba J. , Gajjar Normi D. , Nagar Prinsa R. , Sriram Dharmarajan , Dhameliya Tejas M. 
Published: July 2022

AbstractTuberculosis (TB), an airborne disease caused byMycobacterium tuberculosis, has infected millions of people and been responsible for their deaths. Toward the anti‐TB endeavor, the synthesis of total twenty‐four indole‐2‐carboxamide derivatives as potent anti‐TB agents have been carried out using CDI‐mediated amidation. The biological evaluation against H37Rv revealed compounds5d,5eand5uwith MICs in the range of 3.125‐12.5 μg/mL using MABA assay. Further, compound5uwas tested against RAW 264.7 cell by MTT assay and showed 32 % growth inhibitions. The structure activity relationship of the indole‐2‐carboxamides has been established for antimycobacterial activity. The physicochemical properties and ADMET parameters of the5d,5eand5uusing pKCSM and SwissADME revealed their suitability as promising drug candidates. Molecular docking studies using AutoDock Vina revealed binding of5uwith the catalytic site of mmpL3 (PDB ID: 6AJG). The MD simulations of the most active compound5uusing GROMACS 2020.1 revealed its stability at the protein active site. Further optimization of indole‐2‐carboxamies may reveal the potentiation of identified anti‐mycobacterial drug candidates.