Methylene blue is a popular dye used in the batik industry; however, it potentially causes environmental problems in view of the residual MB content in the liquid waste, which is difficult to naturally degrade. This study aimed to synthesize Fe3O4-TD using tea dregs from household waste and its application as an adsorbent for methylene blue dye. The synthesis was carried out using the reverse co-precipitation method with water as a solvent at room temperature. Fe3O4-TD characterization using FTIR, XRD, and PSA. The adsorption of methylene blue (MB) on Fe3O4-TD was studied at various pH MB, reaction time, and concentration MB to determine the kinetic model and MB adsorption isotherm on Fe3O4-TD and the interactions that occur between MB and Fe3O4-TD. FTIR spectra and X-Ray diffractogram showed that the magnetite formed in a pure state did not mix with other iron oxides. The crystal and particle size of Fe3O4-TD is 18.92 nm and 26.70 µm, respectively. MB adsorption on Fe3O4-TD occurred well at pH > 3 and followed the Ho' pseudo-second-order kinetics model and the Freundlich isotherm model. The interactions between MB and Fe3O4-TD through electrostatic interactions, hydrogen bonds, and phi-phi interactions.
{"title":"Eco-friendly synthesis of magnetite based on tea dregs (Fe3O4-TD) for methylene blue adsorbent from simulation waste","authors":"Maya Rahmayanti, Atika Yahdiyani, Ika Qurrotul Afifah","doi":"10.21924/cst.7.2.2022.965","DOIUrl":"https://doi.org/10.21924/cst.7.2.2022.965","url":null,"abstract":"Methylene blue is a popular dye used in the batik industry; however, it potentially causes environmental problems in view of the residual MB content in the liquid waste, which is difficult to naturally degrade. This study aimed to synthesize Fe3O4-TD using tea dregs from household waste and its application as an adsorbent for methylene blue dye. The synthesis was carried out using the reverse co-precipitation method with water as a solvent at room temperature. Fe3O4-TD characterization using FTIR, XRD, and PSA. The adsorption of methylene blue (MB) on Fe3O4-TD was studied at various pH MB, reaction time, and concentration MB to determine the kinetic model and MB adsorption isotherm on Fe3O4-TD and the interactions that occur between MB and Fe3O4-TD. FTIR spectra and X-Ray diffractogram showed that the magnetite formed in a pure state did not mix with other iron oxides. The crystal and particle size of Fe3O4-TD is 18.92 nm and 26.70 µm, respectively. MB adsorption on Fe3O4-TD occurred well at pH > 3 and followed the Ho' pseudo-second-order kinetics model and the Freundlich isotherm model. The interactions between MB and Fe3O4-TD through electrostatic interactions, hydrogen bonds, and phi-phi interactions.","PeriodicalId":36437,"journal":{"name":"Communications in Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44970782","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}
Pub Date : 2022-12-28DOI: 10.21924/cst.7.2.2022.1041
D. R. Wicakso, A. Mirwan, Era Agustin, Nova Fitria Nopembriani, Ikhsan Firdaus, Muhammad Fadillah
Water treatment sludge (WTS) still contains a lot of silica oxide (SiO2) as much as 43.12-66.90% by weight and can act as an adsorbent to be applied to the treatment of Sasirangan wastewater. Silica extraction from WTS was carried out by microwave-assisted leaching, which - compared to conventional extraction - had several advantages including high extraction yields, fast, uniform, and more selective processing time. In addition, Sasirangan liquid waste is a by-product of the dyeing process of Sasirangan cloth, which still contains heavy metals in amounts exceeding the quality standard. This study aims to extract silica from WTS by microwave-assisted leaching process to synthesize silica modified by chitosan (Si-Kit) as an adsorbent to reduce Pb(II) from Sasirangan wastewater, and to obtain a kinetic model of the adsorption process. The silica from microwave-assisted leaching process (Si-MaL) and Si-Kit adsorbents were characterized using FTIR and SEM. The results showed that the dominant functional groups of Si-Kit included Si-O-Si, Si-O-C stretching vibrations, and stretching vibration of C=N showing that the condensation between aldehyde groups and amino groups occurred to form base after the addition of glutaraldehyde. The SEM images showed that Si-MaL and Si-Kit adsorbent obviously increased in particle size with the presence of visible particles of homogeneous granules and large pores. The removal efficiency percentage of Pb(II) and color occurred at 6% w/v adsorbent weight and 70 min was 87.20% and 61.87% respectively. Meanwhile, the adsorption kinetics of Pb(II) and color followed the zero order kinetics model at weight variation of 6%-w/v based on the value of R2 close to one and the adsorption capacity of Pb(II) ion and color were 12.01 mg g-1 and 467 mg g-1, respectively.
{"title":"Potential of silica from water treatment sludge modified with chitosan for Pb(II) and color adsorption in sasirangan waste solution","authors":"D. R. Wicakso, A. Mirwan, Era Agustin, Nova Fitria Nopembriani, Ikhsan Firdaus, Muhammad Fadillah","doi":"10.21924/cst.7.2.2022.1041","DOIUrl":"https://doi.org/10.21924/cst.7.2.2022.1041","url":null,"abstract":"Water treatment sludge (WTS) still contains a lot of silica oxide (SiO2) as much as 43.12-66.90% by weight and can act as an adsorbent to be applied to the treatment of Sasirangan wastewater. Silica extraction from WTS was carried out by microwave-assisted leaching, which - compared to conventional extraction - had several advantages including high extraction yields, fast, uniform, and more selective processing time. In addition, Sasirangan liquid waste is a by-product of the dyeing process of Sasirangan cloth, which still contains heavy metals in amounts exceeding the quality standard. This study aims to extract silica from WTS by microwave-assisted leaching process to synthesize silica modified by chitosan (Si-Kit) as an adsorbent to reduce Pb(II) from Sasirangan wastewater, and to obtain a kinetic model of the adsorption process. The silica from microwave-assisted leaching process (Si-MaL) and Si-Kit adsorbents were characterized using FTIR and SEM. The results showed that the dominant functional groups of Si-Kit included Si-O-Si, Si-O-C stretching vibrations, and stretching vibration of C=N showing that the condensation between aldehyde groups and amino groups occurred to form base after the addition of glutaraldehyde. The SEM images showed that Si-MaL and Si-Kit adsorbent obviously increased in particle size with the presence of visible particles of homogeneous granules and large pores. The removal efficiency percentage of Pb(II) and color occurred at 6% w/v adsorbent weight and 70 min was 87.20% and 61.87% respectively. Meanwhile, the adsorption kinetics of Pb(II) and color followed the zero order kinetics model at weight variation of 6%-w/v based on the value of R2 close to one and the adsorption capacity of Pb(II) ion and color were 12.01 mg g-1 and 467 mg g-1, respectively.","PeriodicalId":36437,"journal":{"name":"Communications in Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44070894","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}
Pub Date : 2022-12-28DOI: 10.21924/cst.7.2.2022.963
R. Retnosari, Karina Kurnia Sari, S. Marfu’ah, Sutrisno, I. B. Rachman
In recent years, the need for compounds with antioxidant activities have expanded. Generally, the natures of these compounds involve the presence of conjugated double bonds, phenolic groups, and resonance effects on the structure. One of the compounds with the phenolic group is vanillin. It can be modified into the derivative of 1,8-dioxo-octahydroxantene compound due to its aldehyde content. Meanwhile, 1,8-dioxo-octahydroxantene compound has two 2- cyclohexenone rings bound in the pyran ring and one phenolic group, expected to carry more excellent antioxidant activity than vanillin. The 9-(4-hydroxy-3-methoxyphenyl)-3,4,5,6,7,9- hexahydro -1H-xantene-1,8(2H)-dione (Compound 1) was synthesized from 1,3- cyclohexanedione and vanillin through Knoevenagel's condensation reaction aided with an acid catalyst with a single reaction phase. Besides, green chemistry was adopted in this study using environmentally friendly catalysts from lime juice and ultrasonic wave. The synthesized compounds' structure was confirmed through the spectrophotometer IR, GC-MS, and 1H-NMR spectrometer, while its antioxidant activity was tested using the DPPH method. The reaction occurred with and without lime juice catalyst, producing yields of 6.65% and 70.58%, respectively. The results of the antioxidant activity test suggest that Compound 1 carries substantially robust antioxidant activities, with IC50 of 0.99 ppm.
{"title":"Assisted ultrasonic wave of vanillin derivatives synthesis and antioxidant activity using DPPH method","authors":"R. Retnosari, Karina Kurnia Sari, S. Marfu’ah, Sutrisno, I. B. Rachman","doi":"10.21924/cst.7.2.2022.963","DOIUrl":"https://doi.org/10.21924/cst.7.2.2022.963","url":null,"abstract":"In recent years, the need for compounds with antioxidant activities have expanded. Generally, the natures of these compounds involve the presence of conjugated double bonds, phenolic groups, and resonance effects on the structure. One of the compounds with the phenolic group is vanillin. It can be modified into the derivative of 1,8-dioxo-octahydroxantene compound due to its aldehyde content. Meanwhile, 1,8-dioxo-octahydroxantene compound has two 2- cyclohexenone rings bound in the pyran ring and one phenolic group, expected to carry more excellent antioxidant activity than vanillin. The 9-(4-hydroxy-3-methoxyphenyl)-3,4,5,6,7,9- hexahydro -1H-xantene-1,8(2H)-dione (Compound 1) was synthesized from 1,3- cyclohexanedione and vanillin through Knoevenagel's condensation reaction aided with an acid catalyst with a single reaction phase. Besides, green chemistry was adopted in this study using environmentally friendly catalysts from lime juice and ultrasonic wave. The synthesized compounds' structure was confirmed through the spectrophotometer IR, GC-MS, and 1H-NMR spectrometer, while its antioxidant activity was tested using the DPPH method. The reaction occurred with and without lime juice catalyst, producing yields of 6.65% and 70.58%, respectively. The results of the antioxidant activity test suggest that Compound 1 carries substantially robust antioxidant activities, with IC50 of 0.99 ppm.","PeriodicalId":36437,"journal":{"name":"Communications in Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42014170","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}
Pub Date : 2022-12-28DOI: 10.21924/cst.7.2.2022.1004
N. Munandar, S. Kasim, R. Arfah, Djabal Nur Basir, Y. Hala, M. Zakir, H. Natsir
Our present study describes the green synthesis of copper oxide nanoparticles (CuONPs) using a leaf extract from Anredera cordifolia (AC). The presence of flavonoids, saponins, and alkaloids in the plant extract was confirmed by phytochemical analysis, and these chemicals can be used as reducing, stabilizing, and capping agents. UV-Vis Spectrophotometry, XRD, FT-IR, and SEM-EDS were used to characterize the CuONPs. The UV-Vis spectroscopy of the biosynthesized CuONPs revealed an absorption peak at 325 nm. The XRD graph also revealed that the Debye-Scherrer formula observed an average crystalline size of around 43.47 nm. EDS analysis confirmed the composition and purity of CuONPs. The presence of functional groups -OH, C=O, and C-O triggers the synthesis of CuONPs, according to FT-IR analysis. Furthermore, the CuONPs antioxidant property inhibited free radicals as antioxidants with an IC50 value of 34.20 g/mL.
{"title":"Green synthesis of copper oxide (CuO) nanoparticles using Anredera cordifolia leaf extract and their antioxidant activity","authors":"N. Munandar, S. Kasim, R. Arfah, Djabal Nur Basir, Y. Hala, M. Zakir, H. Natsir","doi":"10.21924/cst.7.2.2022.1004","DOIUrl":"https://doi.org/10.21924/cst.7.2.2022.1004","url":null,"abstract":"Our present study describes the green synthesis of copper oxide nanoparticles (CuONPs) using a leaf extract from Anredera cordifolia (AC). The presence of flavonoids, saponins, and alkaloids in the plant extract was confirmed by phytochemical analysis, and these chemicals can be used as reducing, stabilizing, and capping agents. UV-Vis Spectrophotometry, XRD, FT-IR, and SEM-EDS were used to characterize the CuONPs. The UV-Vis spectroscopy of the biosynthesized CuONPs revealed an absorption peak at 325 nm. The XRD graph also revealed that the Debye-Scherrer formula observed an average crystalline size of around 43.47 nm. EDS analysis confirmed the composition and purity of CuONPs. The presence of functional groups -OH, C=O, and C-O triggers the synthesis of CuONPs, according to FT-IR analysis. Furthermore, the CuONPs antioxidant property inhibited free radicals as antioxidants with an IC50 value of 34.20 g/mL.","PeriodicalId":36437,"journal":{"name":"Communications in Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49022609","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}
Pub Date : 2022-07-31DOI: 10.21924/cst.7.1.2022.757
A. B. Nandiyanto, R. Ragadhita, M. Fiandini, Dwi Fitria Al Husaeni, Dwi Novia Al Husaeni, F. Fadhillah
The objective of this study is to develop a new environmentally-friendly brake pad made from eggshells (Es) and banana peels (BPs) as reinforcement agents. E and BP particles as dual reinforcement with various compositions were combined. The E/BP mixture was then embedded on a polymer matrix composing a resin/hardener mixture in a 1:1 ratio. As a standard, brake pads using a single reinforcement of E and BP particles were also fabricated. Physical properties (i.e. particle size, surface roughness, morphology, and density), as well as mechanical properties (i.e. hardness, wear rate, and friction coefficient properties) were investigated. It was observed that using dual reinforcements was preferable (compared to using single reinforcements) because they had a synergistic effect on the mechanical properties of the brake pad. The best mechanical properties were found in dual reinforcements of brake pad specimens using E/BP particles with a higher BP ratio in which the value of the stiffness test, puncture test, wear rate, and coefficient of friction were 4.5 MPa, 86.80, 0.093×10-4 g/s.mm2, and 1.67×10-4, respectively. A high BP particle ratio played a dominant role in dual reinforcements, increasing the resin's bonding ability and resulting in good adhesion between the reinforcement and matrix. When compared to commercial brake pads, the brake pad specimens fabricated in this study met the standards. The techno-economic analysis also confirmed the prospective production of brake pads from E and BP particles (compared to commercial brake pads). From this research, it is expected that environmentally friendly and low-cost brake pads can be used to replace the dangerous friction materials.
{"title":"Domestic waste (eggshells and banana peels particles) as sustainable and renewable resources for improving resin-based brakepad performance: Bibliometric literature review, techno-economic analysis, dual-sized reinforcing experiments, to comparison ...","authors":"A. B. Nandiyanto, R. Ragadhita, M. Fiandini, Dwi Fitria Al Husaeni, Dwi Novia Al Husaeni, F. Fadhillah","doi":"10.21924/cst.7.1.2022.757","DOIUrl":"https://doi.org/10.21924/cst.7.1.2022.757","url":null,"abstract":"The objective of this study is to develop a new environmentally-friendly brake pad made from eggshells (Es) and banana peels (BPs) as reinforcement agents. E and BP particles as dual reinforcement with various compositions were combined. The E/BP mixture was then embedded on a polymer matrix composing a resin/hardener mixture in a 1:1 ratio. As a standard, brake pads using a single reinforcement of E and BP particles were also fabricated. Physical properties (i.e. particle size, surface roughness, morphology, and density), as well as mechanical properties (i.e. hardness, wear rate, and friction coefficient properties) were investigated. It was observed that using dual reinforcements was preferable (compared to using single reinforcements) because they had a synergistic effect on the mechanical properties of the brake pad. The best mechanical properties were found in dual reinforcements of brake pad specimens using E/BP particles with a higher BP ratio in which the value of the stiffness test, puncture test, wear rate, and coefficient of friction were 4.5 MPa, 86.80, 0.093×10-4 g/s.mm2, and 1.67×10-4, respectively. A high BP particle ratio played a dominant role in dual reinforcements, increasing the resin's bonding ability and resulting in good adhesion between the reinforcement and matrix. When compared to commercial brake pads, the brake pad specimens fabricated in this study met the standards. The techno-economic analysis also confirmed the prospective production of brake pads from E and BP particles (compared to commercial brake pads). From this research, it is expected that environmentally friendly and low-cost brake pads can be used to replace the dangerous friction materials.","PeriodicalId":36437,"journal":{"name":"Communications in Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43574363","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}
Pub Date : 2022-07-31DOI: 10.21924/cst.7.1.2022.681
Yusnimar, Evelyn, Azka Aman, Chairul, Suci Rahmadahana, A. Amri
The need of dissolving pulp (DP) for rayon fiber production is increasing rapidly in recent years. Sustainable sources of DP raw materials and an effective manufacturing process are urgently required. This study aims to manufacture dissolving pulp (DP) with high brightness from Sansevieria-trifasciata (ST) fiber through the pre-hydrolysis, soda-Anthraquinone (Soda-AQ) cooking, and chlorine-free bleaching processes. The cellulose content, kappa number, pulp yield, and viscosity were analyzed. The results showed that the ?-cellulose content in ST raw material (39.43%) was relatively similar to the ?-cellulose content in Acacia pulping kraft (39.2%). Furthermore, the variations in pre-hydrolysis time affected the Kappa number, pulp yield, and viscosity. The DP obtained by the elementary chlorine-free (ECF) bleaching process had a viscosity of 9.3 cP, ?-cellulose content of 97.7%, and the brightness of 90.1% which was higher than the ISO standard of pulp brightness. The high DP brightness obtained from this unique combination of pre-hydrolysis, soda-AQ cooking and chlorine-free bleaching sequences has great potential for further development, as it can be used in viscose rayon staple fibers production.
{"title":"Manufacturing of high brightness dissolving pulp from sansevieria-trifasciata fiber by effective sequences processes","authors":"Yusnimar, Evelyn, Azka Aman, Chairul, Suci Rahmadahana, A. Amri","doi":"10.21924/cst.7.1.2022.681","DOIUrl":"https://doi.org/10.21924/cst.7.1.2022.681","url":null,"abstract":"The need of dissolving pulp (DP) for rayon fiber production is increasing rapidly in recent years. Sustainable sources of DP raw materials and an effective manufacturing process are urgently required. This study aims to manufacture dissolving pulp (DP) with high brightness from Sansevieria-trifasciata (ST) fiber through the pre-hydrolysis, soda-Anthraquinone (Soda-AQ) cooking, and chlorine-free bleaching processes. The cellulose content, kappa number, pulp yield, and viscosity were analyzed. The results showed that the ?-cellulose content in ST raw material (39.43%) was relatively similar to the ?-cellulose content in Acacia pulping kraft (39.2%). Furthermore, the variations in pre-hydrolysis time affected the Kappa number, pulp yield, and viscosity. The DP obtained by the elementary chlorine-free (ECF) bleaching process had a viscosity of 9.3 cP, ?-cellulose content of 97.7%, and the brightness of 90.1% which was higher than the ISO standard of pulp brightness. The high DP brightness obtained from this unique combination of pre-hydrolysis, soda-AQ cooking and chlorine-free bleaching sequences has great potential for further development, as it can be used in viscose rayon staple fibers production.","PeriodicalId":36437,"journal":{"name":"Communications in Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48363033","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}
Pub Date : 2022-07-31DOI: 10.21924/cst.7.1.2022.799
Panisa Michu, Pimprapa Chaijak
The ceramic separator has been interested in low-cost alternative proton exchange membranes in a microbial fuel cell (MFC). In this study, the silica-modified ceramic separator has been integrated with the yeast-based MFC for electricity generation and phenol treatment from the winery wastewater. The 30% (w/w) silica powder was mixed with the 70% (w/w) natural clay. The modified ceramic plates (0.2, 0.5, and 1.0 cm of thickness) were prepared at 680°C and used for MFC operation. As an anolyte, synthetic winery wastewater (2,000 mg COD/L and 100 mg/L phenol) with 5% (v/v) ethanol was used. The ethanol-tolerant yeast Pichia sp. ET-KK was used as an anodic catalyst. The results showed the maximal power density of 0.212 W/m2 and phenol removal of 95.05% were reached from the 0.2-thick ceramic plate integrated MFC. This study demonstrated that the silica-modified ceramic separator has a high potential for enhancing electricity generation in the yeast-based MFC.
{"title":"Electricity generation and winery wastewater treatment using silica modified ceramic separator integrated with yeast-based microbial fuel cell","authors":"Panisa Michu, Pimprapa Chaijak","doi":"10.21924/cst.7.1.2022.799","DOIUrl":"https://doi.org/10.21924/cst.7.1.2022.799","url":null,"abstract":"The ceramic separator has been interested in low-cost alternative proton exchange membranes in a microbial fuel cell (MFC). In this study, the silica-modified ceramic separator has been integrated with the yeast-based MFC for electricity generation and phenol treatment from the winery wastewater. The 30% (w/w) silica powder was mixed with the 70% (w/w) natural clay. The modified ceramic plates (0.2, 0.5, and 1.0 cm of thickness) were prepared at 680°C and used for MFC operation. As an anolyte, synthetic winery wastewater (2,000 mg COD/L and 100 mg/L phenol) with 5% (v/v) ethanol was used. The ethanol-tolerant yeast Pichia sp. ET-KK was used as an anodic catalyst. The results showed the maximal power density of 0.212 W/m2 and phenol removal of 95.05% were reached from the 0.2-thick ceramic plate integrated MFC. This study demonstrated that the silica-modified ceramic separator has a high potential for enhancing electricity generation in the yeast-based MFC.","PeriodicalId":36437,"journal":{"name":"Communications in Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45011765","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}
Pub Date : 2022-07-31DOI: 10.21924/cst.7.1.2022.823
T. Prayitno
Available reports mentioned that the magnetic ground state in the AA-stacked bilayer zigzag graphene nanoribbons is the non-magnetic state. As a consequence, it is impossible to exploit magnetism for future electronic devices. This paper aims to show how to generate magnetism in the AA-stacked bilayer zigzag graphene nanoribbons by employing ?rst-principles calculations. As we stacked different ribbon widths, the magnetic ground states appeared for all the thicknesses. In general, the G-type antiferromagnetic state, which is the antiferromagnetic alignment between both intraplane- and interplane-edge carbon atoms, is the ground state for all the thicknesses. We also found that the degenerate magnetic ground states and excited states may appear under certain thicknesses, thus yielding the richness of the magnetic state. As hole-electron doping was applied, a phase transition of magnetic ground state emerged for certain thicknesses, indicating that a new magnetic ground state in the AA-stacked bilayer zigzag graphene nanoribbons can be tuned by the doping.
{"title":"Tuning the magnetic states in AA-stacked bilayer zigzag graphene nanoribbons","authors":"T. Prayitno","doi":"10.21924/cst.7.1.2022.823","DOIUrl":"https://doi.org/10.21924/cst.7.1.2022.823","url":null,"abstract":"Available reports mentioned that the magnetic ground state in the AA-stacked bilayer zigzag graphene nanoribbons is the non-magnetic state. As a consequence, it is impossible to exploit magnetism for future electronic devices. This paper aims to show how to generate magnetism in the AA-stacked bilayer zigzag graphene nanoribbons by employing ?rst-principles calculations. As we stacked different ribbon widths, the magnetic ground states appeared for all the thicknesses. In general, the G-type antiferromagnetic state, which is the antiferromagnetic alignment between both intraplane- and interplane-edge carbon atoms, is the ground state for all the thicknesses. We also found that the degenerate magnetic ground states and excited states may appear under certain thicknesses, thus yielding the richness of the magnetic state. As hole-electron doping was applied, a phase transition of magnetic ground state emerged for certain thicknesses, indicating that a new magnetic ground state in the AA-stacked bilayer zigzag graphene nanoribbons can be tuned by the doping.","PeriodicalId":36437,"journal":{"name":"Communications in Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48393514","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}
Pub Date : 2022-07-31DOI: 10.21924/cst.7.1.2022.661
L. M. Quynh, Hoang Van Huy, Nguyen Duy Thien, Le Thi Cam Van, L. Dũng
Marine diatoms play a very crucial role in carbon export, and current food-web and become an important factor in global silica cycle. This then has made the mechanism of their biosilicification interesting to be a research subject. The classical theory states that the silica metabolism has been originated from the absorption of silicate ions, which might not give a suitable explanation for the solid silica silicification. In this study, mono-disperse Si/SiO2 fluorescent submicron-spheres were synthesized in aqueous solution, and applied in monitoring the extracellular solid silica accumulation of Chaetoceros sp. diatom. The Si/SiO2 submicron particles emitted light-blue color with the spectrum centered at 440 nm under the excitation of 365 nm UV light, similar to the typical excitation/emission pair of the DAPI fluorophore (excitation/emission: 358 nm/461 nm). The fluorescence-microscopic investigation showed that the Si/SiO2 particles delocalized on the diatoms’ surface and increased a silicic-acid-level surrounding the microalgae. As a consequence, the growth rate of the diatoms increased as the concentration of the SiO2 particles was at 120 mg/L, and reached 1.5 times higher than the growth rate calculated from the F2 media. The study not only introduces a new aspect to the extracellular metabolism of microalgae biosilicification corresponding to the global silica cycle, but also presents a new-type of culturing media using SiO2 nanoparticles for diatom cultivation, which increases the growth rate of artificial diatom-culturing for further applications.
{"title":"Synthesis of Si/SiO2 core/shell fluorescent submicron-spheres for monitoring the accumulation of colloidal silica during the growth of diatom Chaetoceros sp.","authors":"L. M. Quynh, Hoang Van Huy, Nguyen Duy Thien, Le Thi Cam Van, L. Dũng","doi":"10.21924/cst.7.1.2022.661","DOIUrl":"https://doi.org/10.21924/cst.7.1.2022.661","url":null,"abstract":"Marine diatoms play a very crucial role in carbon export, and current food-web and become an important factor in global silica cycle. This then has made the mechanism of their biosilicification interesting to be a research subject. The classical theory states that the silica metabolism has been originated from the absorption of silicate ions, which might not give a suitable explanation for the solid silica silicification. In this study, mono-disperse Si/SiO2 fluorescent submicron-spheres were synthesized in aqueous solution, and applied in monitoring the extracellular solid silica accumulation of Chaetoceros sp. diatom. The Si/SiO2 submicron particles emitted light-blue color with the spectrum centered at 440 nm under the excitation of 365 nm UV light, similar to the typical excitation/emission pair of the DAPI fluorophore (excitation/emission: 358 nm/461 nm). The fluorescence-microscopic investigation showed that the Si/SiO2 particles delocalized on the diatoms’ surface and increased a silicic-acid-level surrounding the microalgae. As a consequence, the growth rate of the diatoms increased as the concentration of the SiO2 particles was at 120 mg/L, and reached 1.5 times higher than the growth rate calculated from the F2 media. The study not only introduces a new aspect to the extracellular metabolism of microalgae biosilicification corresponding to the global silica cycle, but also presents a new-type of culturing media using SiO2 nanoparticles for diatom cultivation, which increases the growth rate of artificial diatom-culturing for further applications.","PeriodicalId":36437,"journal":{"name":"Communications in Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48539399","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}
Pub Date : 2022-07-31DOI: 10.21924/cst.7.1.2022.746
Muhammad Dzulqarnain Al Firdausi, Shafiq Ahmad
Fault detection is an urgent need for maintenance to obtain the optimal scheduling of production activities, improve system reliability, and reduce operation and maintenance costs. Many studies published in recent years focus on machine learning models to detect any system anomalies in line with the era of big data and the fourth industrial revolution (Industry 4.0). Say, a working condition of bearing can be monitored and then any fault can be detected using the vibration analysis of bearing acceleration data. Most of the published works are presented based upon the knowledge of signal processing in which the result depends heavily on feature extraction. It becomes a challenge then to apply a machine learning algorithm directly to the raw acceleration data as it has been successfully applied to raw data in other science and engineering domains. In this article, a concise Convolutional Neural Networks-based deep learning model is proposed for bearing fault detection. The proposed model was concise with 98% less number of parameters compared to other well-known models. It produced 21.21% and 7.03% better accuracy and fault detection rate, respectively. The model was also tested in different operating parameter environments and still gave an excellent result. Since the proposed concise architecture of the model needed short training time, it is deemed suitable for application on manufacturing floor where the pace of production moves fast and the change of the production machine configuration likely occurs.
{"title":"Concise convolutional neural network model for fault detection","authors":"Muhammad Dzulqarnain Al Firdausi, Shafiq Ahmad","doi":"10.21924/cst.7.1.2022.746","DOIUrl":"https://doi.org/10.21924/cst.7.1.2022.746","url":null,"abstract":"Fault detection is an urgent need for maintenance to obtain the optimal scheduling of production activities, improve system reliability, and reduce operation and maintenance costs. Many studies published in recent years focus on machine learning models to detect any system anomalies in line with the era of big data and the fourth industrial revolution (Industry 4.0). Say, a working condition of bearing can be monitored and then any fault can be detected using the vibration analysis of bearing acceleration data. Most of the published works are presented based upon the knowledge of signal processing in which the result depends heavily on feature extraction. It becomes a challenge then to apply a machine learning algorithm directly to the raw acceleration data as it has been successfully applied to raw data in other science and engineering domains. In this article, a concise Convolutional Neural Networks-based deep learning model is proposed for bearing fault detection. The proposed model was concise with 98% less number of parameters compared to other well-known models. It produced 21.21% and 7.03% better accuracy and fault detection rate, respectively. The model was also tested in different operating parameter environments and still gave an excellent result. Since the proposed concise architecture of the model needed short training time, it is deemed suitable for application on manufacturing floor where the pace of production moves fast and the change of the production machine configuration likely occurs.","PeriodicalId":36437,"journal":{"name":"Communications in Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41968881","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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