S. Ambika, S. Gopinath, K. Sivakumar, K. Saravanan
A series of cobalt oxide nanoparticles (sample A (300 °C), sample B (400 °C) and sample C (500 °C)) are synthesized in a starch medium by the hydrothermal method followed by annealing. The structural, morphological, and magnetic, of these cobalt oxide nanoparticles, become characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) correspondingly. Furthermore, it can be seen that the increase in the synthesis temperature results in a substantial increase in the average particle size. The impact of synthesis temperature in relation to morphology (size and shape) and magnetic properties of cobalt oxide nanoparticles has been investigated. Besides, the antibacterial and catalytic activity of these nanoparticles are examined. A systematic analysis is presented on the influence of parameters of synthesis on the formation and structural properties of cobalt oxide nanoparticles. We expect in which this topic will give many valuable ideas for the metal oxide nanomaterials development, synthesis, as well as applications.
{"title":"Spinel-Type Cobalt Oxide Nanoparticles: Synthesis, Characterization and Antibacterial Properties","authors":"S. Ambika, S. Gopinath, K. Sivakumar, K. Saravanan","doi":"10.1166/asem.2020.2623","DOIUrl":"https://doi.org/10.1166/asem.2020.2623","url":null,"abstract":"A series of cobalt oxide nanoparticles (sample A (300 °C), sample B (400 °C) and sample C (500 °C)) are synthesized in a starch medium by the hydrothermal method followed by annealing. The structural, morphological, and magnetic, of these cobalt oxide nanoparticles, become\u0000 characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) correspondingly. Furthermore, it can be seen that the increase in the synthesis temperature results in a substantial increase in the average\u0000 particle size. The impact of synthesis temperature in relation to morphology (size and shape) and magnetic properties of cobalt oxide nanoparticles has been investigated. Besides, the antibacterial and catalytic activity of these nanoparticles are examined. A systematic analysis is presented\u0000 on the influence of parameters of synthesis on the formation and structural properties of cobalt oxide nanoparticles. We expect in which this topic will give many valuable ideas for the metal oxide nanomaterials development, synthesis, as well as applications.","PeriodicalId":7213,"journal":{"name":"Advanced Science, Engineering and Medicine","volume":"463 1","pages":"859-863"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87895707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. L. Costa, S. B. O. Fernandes, C. E. Fingolo, F. Boylan, A. M. J. C. Neto, G. S. Mota, B. A. Soares, M. Siqueira, Thaís Forest Giacomello
Coronaviruses belong to the subfamily Coronavirinae, which are large viruses with a single Ribonucleic acid tape and a nucleocapsid. In a recent study it was found that the molecule of tryptanthrin has antiviral potential against human coronavirus NL63. In this work, we used a combination of theoretical techniques with experimental nuclear magnetic resonance data to assist in the structural characterization of the Tryptanthrin molecule. Tryptanthrin was extracted from Couroupita guianensis leaves. The theoretical calculations of hydrogen-1, homonuclear spin–spin coupling constants and the quantum theory of atoms in molecules were performed employing density functional theory. Our results show that the hydrogen-1 chemical shifts calculated at the gaseous phase and solvent presented similar performance. The quantum theory of atoms in molecules calculations was able to quantify and qualify bonded interactions based on five topological parameters obtained at the analyzed bond critical point to tryptanthrin molecule. We obtained a satisfactory correlation between tryptanthrin delocalization index values and its experimental and calculated proton–proton coupling constants. In conclusion, the theoretical techniques used in this work in combination with NMR experimental data can be a useful tool in aiding the structural determination of organic compounds.
{"title":"Experimental and Theoretical Nuclear Magnetic Resonance Data from Tryptanthrin, an Alkaloid with Potential Activity Against Human Coronavirus","authors":"F. L. Costa, S. B. O. Fernandes, C. E. Fingolo, F. Boylan, A. M. J. C. Neto, G. S. Mota, B. A. Soares, M. Siqueira, Thaís Forest Giacomello","doi":"10.1166/asem.2020.2638","DOIUrl":"https://doi.org/10.1166/asem.2020.2638","url":null,"abstract":"Coronaviruses belong to the subfamily Coronavirinae, which are large viruses with a single Ribonucleic acid tape and a nucleocapsid. In a recent study it was found that the molecule of tryptanthrin has antiviral potential against human coronavirus NL63. In this work, we used\u0000 a combination of theoretical techniques with experimental nuclear magnetic resonance data to assist in the structural characterization of the Tryptanthrin molecule. Tryptanthrin was extracted from Couroupita guianensis leaves. The theoretical calculations of hydrogen-1, homonuclear\u0000 spin–spin coupling constants and the quantum theory of atoms in molecules were performed employing density functional theory. Our results show that the hydrogen-1 chemical shifts calculated at the gaseous phase and solvent presented similar performance. The quantum theory of atoms in\u0000 molecules calculations was able to quantify and qualify bonded interactions based on five topological parameters obtained at the analyzed bond critical point to tryptanthrin molecule. We obtained a satisfactory correlation between tryptanthrin delocalization index values and its experimental\u0000 and calculated proton–proton coupling constants. In conclusion, the theoretical techniques used in this work in combination with NMR experimental data can be a useful tool in aiding the structural determination of organic compounds.","PeriodicalId":7213,"journal":{"name":"Advanced Science, Engineering and Medicine","volume":"45 1","pages":"963-969"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81021996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. A. Mohammed, Azhar A. Habieb, Ahmed O. Swary, Dalal N. Ahilfi, D. K. Thbayh
Noble metals gold NPs are produced by pulsed (“Q-switched, 1064 nm Nd: YAG”) ablation of gold foil dipped in doubles distilled water DDW by laser. (PLAL) the process was performed with laser energy in range (400–700) mJ at (90 pulses, wavelength 1064 and room temperature and liquid depth 9 mm. The influence of laser energies have been tested structurally, optically and morphologically and examined by using scanning electron microscope (SEM), UV-visible spectroscopy and atomic force microscope (AFM). The absorption spectra of AuNPs are prepared in water piercing and solitary peaks nearby 518 and 524 nm, demonstrating the assembly of clean and sphericals in shape AuNPs with the middling size in the range of (20–50) nm. SEM and AFM have established all the measurements of size.
{"title":"Effect of Laser Energy on Optical and Morphological Properties of Gold Nanoparticles","authors":"K. A. Mohammed, Azhar A. Habieb, Ahmed O. Swary, Dalal N. Ahilfi, D. K. Thbayh","doi":"10.1166/asem.2020.2662","DOIUrl":"https://doi.org/10.1166/asem.2020.2662","url":null,"abstract":"Noble metals gold NPs are produced by pulsed (“Q-switched, 1064 nm Nd: YAG”) ablation of gold foil dipped in doubles distilled water DDW by laser. (PLAL) the process was performed with laser energy in range (400–700) mJ at (90 pulses, wavelength 1064 and room temperature\u0000 and liquid depth 9 mm. The influence of laser energies have been tested structurally, optically and morphologically and examined by using scanning electron microscope (SEM), UV-visible spectroscopy and atomic force microscope (AFM). The absorption spectra of AuNPs are prepared in water piercing\u0000 and solitary peaks nearby 518 and 524 nm, demonstrating the assembly of clean and sphericals in shape AuNPs with the middling size in the range of (20–50) nm. SEM and AFM have established all the measurements of size.","PeriodicalId":7213,"journal":{"name":"Advanced Science, Engineering and Medicine","volume":"52 Suppl 1 1","pages":"989-993"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89335626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. R. Souza, K. Bonfim, M. V. Lorevice, D. Correa, L. Mattoso, M. R. Moura
This work describes an outstanding synthesis of poly(ε-caprolactone) nanoparticles of distinct sizes loaded (PCLNP/OEO) or not (PCLNP) with oregano (Origanum vulgare) essential oil (OEO) by the nanoprecipitation method in order investigate the antimicrobial properties against bacteria Escherichia coli and Staphylococcus aureus. OEO antimicrobial activity was achieved by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). FTIR spectra indicated that encapsulation of OEO by PCLNPs was successful. Scanning electron microscopy images revealed that PCLNP and PCLNP/OEO presented spherical shape with diameters around 150 nm, while PCLNP exhibited size distribution raging 158 to 300 nm and zeta potential ranging from -13.8 to -28.5 mV. Thermogravimetric analysis indicated an increase in initial temperature of weight loss for PCLNP/OEO. PCLNP with 80% wt. of OEO has exhibited the highest decrease of growth of bacteria, and MIC against S. aureus and E. coli and MBC only for E. coli, which indicate a promising alternative for designing stable antimicrobial nanoparticles for application in novel food active packaging.
{"title":"Antibacterial Properties of Oregano Essential Oil Encapsulated in Poly(ε-Caprolactone) Nanoparticles","authors":"J. R. Souza, K. Bonfim, M. V. Lorevice, D. Correa, L. Mattoso, M. R. Moura","doi":"10.1166/asem.2020.2626","DOIUrl":"https://doi.org/10.1166/asem.2020.2626","url":null,"abstract":"This work describes an outstanding synthesis of poly(ε-caprolactone) nanoparticles of distinct sizes loaded (PCLNP/OEO) or not (PCLNP) with oregano (Origanum vulgare) essential oil (OEO) by the nanoprecipitation method in order investigate the antimicrobial properties against\u0000 bacteria Escherichia coli and Staphylococcus aureus. OEO antimicrobial activity was achieved by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). FTIR spectra indicated that encapsulation of OEO by PCLNPs was successful. Scanning electron microscopy\u0000 images revealed that PCLNP and PCLNP/OEO presented spherical shape with diameters around 150 nm, while PCLNP exhibited size distribution raging 158 to 300 nm and zeta potential ranging from -13.8 to -28.5 mV. Thermogravimetric analysis indicated an increase in initial temperature of weight\u0000 loss for PCLNP/OEO. PCLNP with 80% wt. of OEO has exhibited the highest decrease of growth of bacteria, and MIC against S. aureus and E. coli and MBC only for E. coli, which indicate a promising alternative for designing stable antimicrobial nanoparticles for application\u0000 in novel food active packaging.","PeriodicalId":7213,"journal":{"name":"Advanced Science, Engineering and Medicine","volume":"8 1","pages":"864-869"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87083467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Use of swarm intelligence has proliferated over previous couple of years for damage assessment in large and complex structures using vibration data. Available literatures shows ‘ant colony optimization’ (ACO) and ‘particle swarm optimization’ (PSO) are predominantly used for solving complex engineering problems including damage identification and quantification problems. The time requirement and accuracy of the vibration based damage identification algorithms depends on early exploration and late exploitation capabilities of soft computing techniques. However, there are not any literature available comparing algorithms on these bases. In the current study, an inverse problem is constructed using the natural frequency changes which is then solved using ACO and PSO algorithms. The algorithm is run for identification of single and multiple damages in simple support and cantilever beam structures. It's found that, both ACO and PSO based algorithms are capable of detecting and quantifying the damage accurately within the limited number of iterations. However, ACO based algorithm by virtue of its good exploration capability is able to identify near optimal region faster than PSO based algorithm, whereas PSO algorithm has good exploitation capability and hence able to provide better damage quantification than ACO algorithm at latter stages of iteration. Further, PSO based algorithm takes less time to reach at required accuracy level. It is also observed that, the time required for these algorithms are independent of numbers of damage and support conditions.
{"title":"A Comparative Study on Inverse Vibration Based Damage Assessment Techniques in Beam Structure Using Ant Colony Optimization and Particle Swarm Optimization","authors":"Aditi Majumdar, Bharadwaj Nanda","doi":"10.1166/asem.2020.2649","DOIUrl":"https://doi.org/10.1166/asem.2020.2649","url":null,"abstract":"Use of swarm intelligence has proliferated over previous couple of years for damage assessment in large and complex structures using vibration data. Available literatures shows ‘ant colony optimization’ (ACO) and ‘particle swarm optimization’ (PSO) are predominantly\u0000 used for solving complex engineering problems including damage identification and quantification problems. The time requirement and accuracy of the vibration based damage identification algorithms depends on early exploration and late exploitation capabilities of soft computing techniques.\u0000 However, there are not any literature available comparing algorithms on these bases. In the current study, an inverse problem is constructed using the natural frequency changes which is then solved using ACO and PSO algorithms. The algorithm is run for identification of single and multiple\u0000 damages in simple support and cantilever beam structures. It's found that, both ACO and PSO based algorithms are capable of detecting and quantifying the damage accurately within the limited number of iterations. However, ACO based algorithm by virtue of its good exploration capability is\u0000 able to identify near optimal region faster than PSO based algorithm, whereas PSO algorithm has good exploitation capability and hence able to provide better damage quantification than ACO algorithm at latter stages of iteration. Further, PSO based algorithm takes less time to reach at required\u0000 accuracy level. It is also observed that, the time required for these algorithms are independent of numbers of damage and support conditions.","PeriodicalId":7213,"journal":{"name":"Advanced Science, Engineering and Medicine","volume":"41 1","pages":"918-923"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90532798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vishal Kumar, M. Hussain, R. Singh, Shashanka P. Kumar
The present study concentrated on the variation of process parameters on metal removal rate (MRR) used in turning of widely used material (stainless steel 304 and Mild steel). Turning is essential and robust process of material removal in the form of chips. The Turning process involved lots of process parameters as tool geometry, feed rate, rotational speed of job and rigidity of machine tools etc. In the present work study was done on the following cutting parameters as cutting speed (85,150 and 250 rpm), feed rate (0.13, 0.28 and 0.15, 0.09 mm/sec), depth of cut (0.4, 0.7 and 1 mm). The three label orthogonal array for process parameters were selected for metal removal rate analysis. The carbide tipped cutting tool was selected as cutting tool of positive rake angle. The analysis of process parameters was done through Minitab 17 software. The orthogonal array was selected 3*3; by the use of signal to noise (S/N) ratio is to minimise the variation due to uncontrolled parameters with the help of Taguchi method. Total nine experiments were performing on stainless steel and other set of nine experiments were perform on the mild steel. The experimental results reveals that moderate cutting speed 150 rpm, 0.09 mm/sec feed rate and 1 mm depth of cut yield good results for stainless steel 304 grade and mild steel.
{"title":"Comparison of Process Parameters on Mild Steel and SS304 Through Statistical Analysis of Optimization Technique","authors":"Vishal Kumar, M. Hussain, R. Singh, Shashanka P. Kumar","doi":"10.1166/asem.2020.2646","DOIUrl":"https://doi.org/10.1166/asem.2020.2646","url":null,"abstract":"The present study concentrated on the variation of process parameters on metal removal rate (MRR) used in turning of widely used material (stainless steel 304 and Mild steel). Turning is essential and robust process of material removal in the form of chips. The Turning process involved\u0000 lots of process parameters as tool geometry, feed rate, rotational speed of job and rigidity of machine tools etc. In the present work study was done on the following cutting parameters as cutting speed (85,150 and 250 rpm), feed rate (0.13, 0.28 and 0.15, 0.09 mm/sec), depth of cut (0.4,\u0000 0.7 and 1 mm). The three label orthogonal array for process parameters were selected for metal removal rate analysis. The carbide tipped cutting tool was selected as cutting tool of positive rake angle. The analysis of process parameters was done through Minitab 17 software. The orthogonal\u0000 array was selected 3*3; by the use of signal to noise (S/N) ratio is to minimise the variation due to uncontrolled parameters with the help of Taguchi method. Total nine experiments were performing on stainless steel and other set of nine experiments were perform on the mild steel. The experimental\u0000 results reveals that moderate cutting speed 150 rpm, 0.09 mm/sec feed rate and 1 mm depth of cut yield good results for stainless steel 304 grade and mild steel.","PeriodicalId":7213,"journal":{"name":"Advanced Science, Engineering and Medicine","volume":"1764 1","pages":"888-893"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82848356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An ab initio study has been performed for the stability, structural and electronic properties of forty-four ZnxTey (x + y = p = 2 to 5) nanoclusters by employing B3LYP-DFT/LANL2DZ method. The zero-point energy correction is also considered in this study. For a particular configuration, the nanoclusters containing a large number of Te atoms are found the most stable structure in comparison with the other nanoclusters. The most stable nanoclusters have either linear or planer structures and, only Zn4Te configuration has no stable structure as the structures of this configuration have at least one imaginary vibrational frequency. The HOMO–LUMO gap of the most stable structure shows a zigzag variation with the increase in the number of atoms in the nanocluster. The observed enhancement trend of the HOMO–LUMO gap with a decrease in the size of the nanocluster confirms to the quantum-confinement effect. The ionization potential (IP) shows decreasing behavior with an increase in the number of atoms in nanoclusters and the variation of electron affinity (EA) with nanocluster size shows zig-zag behavior.
采用B3LYP-DFT/LANL2DZ方法对44个ZnxTey (x + y = p = 2 ~ 5)纳米团簇的稳定性、结构和电子性能进行了从头算研究。本研究还考虑了零点能量校正。对于特定的结构，与其他纳米簇相比，含有大量Te原子的纳米簇是最稳定的结构。最稳定的纳米团簇要么是线性结构，要么是平面结构，只有Zn4Te构型没有稳定的结构，因为这种构型的结构至少有一个虚振动频率。最稳定结构的HOMO-LUMO隙随着纳米团簇中原子数的增加呈之字形变化。观察到的HOMO-LUMO隙随着纳米团簇尺寸的减小而增强的趋势证实了量子约束效应。电离势(IP)随纳米团簇原子数的增加而减小，电子亲和势(EA)随纳米团簇大小的变化呈锯齿状。
{"title":"Ab-Initio Study of Structural and Electronic Properties of ZnxTey (x + y = 2 to 5) Nanoclusters","authors":"D. Pandey, P. S. Yadav","doi":"10.1166/asem.2020.2634","DOIUrl":"https://doi.org/10.1166/asem.2020.2634","url":null,"abstract":"An ab initio study has been performed for the stability, structural and electronic properties of forty-four ZnxTey (x + y = p = 2 to 5) nanoclusters by employing B3LYP-DFT/LANL2DZ method. The zero-point energy correction is also\u0000 considered in this study. For a particular configuration, the nanoclusters containing a large number of Te atoms are found the most stable structure in comparison with the other nanoclusters. The most stable nanoclusters have either linear or planer structures and, only Zn4Te configuration\u0000 has no stable structure as the structures of this configuration have at least one imaginary vibrational frequency. The HOMO–LUMO gap of the most stable structure shows a zigzag variation with the increase in the number of atoms in the nanocluster. The observed enhancement trend of the\u0000 HOMO–LUMO gap with a decrease in the size of the nanocluster confirms to the quantum-confinement effect. The ionization potential (IP) shows decreasing behavior with an increase in the number of atoms in nanoclusters and the variation of electron affinity (EA) with nanocluster size shows\u0000 zig-zag behavior.","PeriodicalId":7213,"journal":{"name":"Advanced Science, Engineering and Medicine","volume":"170 1","pages":"930-938"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80680017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amongst the various methods of machining, Electro Discharge Machining is the convenient alternatives for the industries due to non-contact of work piece and tool. In the study of various EDM processes the main target is to achieve the better finish of surface, high material removal rate and good dimensional accuracy by regulating the different input parameters. There are various applications of EDM such as aerospace parts, medical equipments, dies and moulds, nuclear and automobile industry. In this experimental study, a trial has made to look the impact of input factors like pulse-on, pulse-off, peak current, tension of wire on rate of material removal, gap current and time for machining. Taguchi (L9 OA) and Analysis of Variance technique were used to optimize the outcomes for wire cut EDM of EN-31 tool steel. The outcomes revealed that Ton and Toff are the leading cogent factor for material removal rate and gap current respectively.
{"title":"Parametric Optimization of EN-31 Steel in Wire Cut Electro Discharge Machining by Taguchi Technique","authors":"Sahil Sharma, U. K. Vates, A. Bansal","doi":"10.1166/asem.2020.2645","DOIUrl":"https://doi.org/10.1166/asem.2020.2645","url":null,"abstract":"Amongst the various methods of machining, Electro Discharge Machining is the convenient alternatives for the industries due to non-contact of work piece and tool. In the study of various EDM processes the main target is to achieve the better finish of surface, high material removal\u0000 rate and good dimensional accuracy by regulating the different input parameters. There are various applications of EDM such as aerospace parts, medical equipments, dies and moulds, nuclear and automobile industry. In this experimental study, a trial has made to look the impact of input factors\u0000 like pulse-on, pulse-off, peak current, tension of wire on rate of material removal, gap current and time for machining. Taguchi (L9 OA) and Analysis of Variance technique were used to optimize the outcomes for wire cut EDM of EN-31 tool steel. The outcomes revealed that Ton and\u0000 Toff are the leading cogent factor for material removal rate and gap current respectively.","PeriodicalId":7213,"journal":{"name":"Advanced Science, Engineering and Medicine","volume":"32 1","pages":"881-887"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73661938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
David Shine, S. Shasha, Alorku Kingdom, Okoampah Emmanuel, S. S. Fometu, Wu Guohua
The toxicity and cost involved in the synthesis of nanoparticles using physical and chemical methods have led to the emergence of biological techniques being employed by scientists. Hence the present study employed an eco-friendly method by using Parkia biglobosa leaves extract as a reducing and stabilizing agent of chloroauric gold (HAuCl4) to gold nanoparticle (AuNPs). Direct Analysis in Real-Time (DART-MS) was employed for phytochemical screening. However, the AuNPs were characterized by Ultraviolet-Visible spectroscopy (UV/Vis), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray spectroscopy, Fourier Transmission Infrared Spectroscopy, and X-ray diffraction spectroscopy, before the antibacterial and photocatalysis study. DART-MS showed more than 20 phytochemicals, including phenolic compounds. The FT-IR revealed the existence of flavonoids that we hypothesized are responsible for gold chloride reduction reactions. The optical properties of the gold nanoparticles by UV/Vis spectra registered plasmon surface resonance at a peak of 530 nm, whiles TEM revealed the AuNPs to be mono-dispersed and shapes were spherical and triangular with sizes ranging from 3.4 nm to 39.7 nm. XRD also recorded face-centered cubic AuNPs with 20.94 nm as the average crystallite size. The synthesized AuNPs were able to elucidate their anti-bacterial efficacy on Gram-positive bacteria Staphylococcus aureus, enterococcus faecalis and Gram-negative bacteria Escherichia coli, pseudomonas aeruginosa. The photocatalytic activities of AuNPs under UV/Vis irradiation exhibited a substantial degradation effect on rhodamine b (RhB) within 75 minutes. Due to their non-toxic nature, plant-mediated biosynthesized AuNPs, would be valuable in enhancing their biomedical applications and in wastewater treatment.
{"title":"Biosynthesizing Gold Nanoparticles with Parkia biglobosa Leaf Extract for Antibacterial Efficacy In Vitro and Photocatalytic Degradation Activities of Rhodamine B Dye","authors":"David Shine, S. Shasha, Alorku Kingdom, Okoampah Emmanuel, S. S. Fometu, Wu Guohua","doi":"10.1166/asem.2020.2661","DOIUrl":"https://doi.org/10.1166/asem.2020.2661","url":null,"abstract":"The toxicity and cost involved in the synthesis of nanoparticles using physical and chemical methods have led to the emergence of biological techniques being employed by scientists. Hence the present study employed an eco-friendly method by using Parkia biglobosa leaves extract\u0000 as a reducing and stabilizing agent of chloroauric gold (HAuCl4) to gold nanoparticle (AuNPs). Direct Analysis in Real-Time (DART-MS) was employed for phytochemical screening. However, the AuNPs were characterized by Ultraviolet-Visible spectroscopy (UV/Vis), Transmission Electron\u0000 Microscopy (TEM), Energy Dispersive X-ray spectroscopy, Fourier Transmission Infrared Spectroscopy, and X-ray diffraction spectroscopy, before the antibacterial and photocatalysis study. DART-MS showed more than 20 phytochemicals, including phenolic compounds. The FT-IR revealed the existence\u0000 of flavonoids that we hypothesized are responsible for gold chloride reduction reactions. The optical properties of the gold nanoparticles by UV/Vis spectra registered plasmon surface resonance at a peak of 530 nm, whiles TEM revealed the AuNPs to be mono-dispersed and shapes were spherical\u0000 and triangular with sizes ranging from 3.4 nm to 39.7 nm. XRD also recorded face-centered cubic AuNPs with 20.94 nm as the average crystallite size. The synthesized AuNPs were able to elucidate their anti-bacterial efficacy on Gram-positive bacteria Staphylococcus aureus, enterococcus faecalis\u0000 and Gram-negative bacteria Escherichia coli, pseudomonas aeruginosa. The photocatalytic activities of AuNPs under UV/Vis irradiation exhibited a substantial degradation effect on rhodamine b (RhB) within 75 minutes. Due to their non-toxic nature, plant-mediated biosynthesized AuNPs,\u0000 would be valuable in enhancing their biomedical applications and in wastewater treatment.","PeriodicalId":7213,"journal":{"name":"Advanced Science, Engineering and Medicine","volume":"152 1","pages":"970-981"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79585417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have investigated the study of double diffusive stationary convection in the presence of applied magnetic field and internal heating. A weakly nonlinear stability analysis has been performed using the finite amplitude Ginzburg-Landau model. This finite amplitude of convection is obtained at third order of the system. It is assumed that the buoyancy term has two parts, steady and oscillatory parts. The second part is varying sinusoidally with time and vibrates the system with finite amplitude δ1 and frequency ω. The effects of δ1 and on heat/mass transports have been analysed and depicted graphically. The studies are established that the heat/mass transports can be controlled effectively by gravity modulation. Further, it is found that internal Rayleigh number Ri is to enhance heat transfer and reduces the mass transfer in the system.
{"title":"The Effect of Gravity Modulation on Double Diffusive Convection in the Presence of Applied Magnetic Field and Internal Heat Source","authors":"P. Kiran, S. Manjula, R. Roslan","doi":"10.1166/asem.2020.2576","DOIUrl":"https://doi.org/10.1166/asem.2020.2576","url":null,"abstract":"We have investigated the study of double diffusive stationary convection in the presence of applied magnetic field and internal heating. A weakly nonlinear stability analysis has been performed using the finite amplitude Ginzburg-Landau model. This finite amplitude of convection is\u0000 obtained at third order of the system. It is assumed that the buoyancy term has two parts, steady and oscillatory parts. The second part is varying sinusoidally with time and vibrates the system with finite amplitude δ1 and frequency ω. The effects of δ1\u0000 and on heat/mass transports have been analysed and depicted graphically. The studies are established that the heat/mass transports can be controlled effectively by gravity modulation. Further, it is found that internal Rayleigh number Ri is to enhance heat transfer and reduces\u0000 the mass transfer in the system.","PeriodicalId":7213,"journal":{"name":"Advanced Science, Engineering and Medicine","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77360310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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