Fabrikasi nanokeramik berbasis ZnFe2O4 ditambah 10% mol Mn2O3 berbahan dasar mineral lokal untuk aplikasi sensor gas alkohol

Fabrikasi Nanokeramik Berbasis ZnFe2O4 ditambah 10% mol Mn2O3 Berbahan Dasar Mineral Lokal Untuk Aplikasi Sensor Gas Alkohol telah berhasil dilakukan. Penelitian ini bertujuan untuk mengoptimalkan potensi mineral yang ada di Indonesia dan mengetahui pengaruh dari suhu pembakaran terhadap karakteristik nanokeramik. Material semikonduktor yang digunakan adalah besi oksida Fe2O3 (hasil pemurnian yarosit), Mn2O3 (hasil pemurnian Manganit) dan ZnO. Sintesis serbuk nanokeramik dilakukan dengan menggunakan metode presipitasi. Serbuk hasil sintesis dicampur dengan Organic Vehicle (OV) untuk dibuat menjadi pasta dengan perbandingan serbuk 70% : OV 30%. Fabrikasi nanokeramik dilakukan menggunakan metode screen printing dengan suhu pembakaran 600 dan 700 oC selama dua jam. Nanokeramik memiliki heterostruktur kubik dan hekasagonal dengan ukuran kristalit ~27 nm dan 125 nm berturut-turut untuk suhu pembakaran 600 dan 700 oC. Pori lebih banyak dihasilkan pada suhu pembakaran 700 oC meskipun dengan ukuran yang lebih kecil. Dimana permukaan keramiknya lebih rata serta memiliki ukuran butir yang seragam. Ini ditunjukkan dengan performa respon sensor yang tinggi terhadap gas alkohol pada suhu kerja 325 oC, dengan nilai konstanta alfa sebesar 1,16. Dimana nilai minimum kostanta alfa sensor komersial adalah satu yang menunjukkan bahwa sensor berpotensi untuk diproduksi secara komersial. Suhu pembakaran berpengaruh terhadap produksi pori dan respon sensor terhadap gas etanol. Dapat disimpulkan bahwa mineral lokal memiliki potensi tinggi dan mampu bersaing dengan material impor sebagai prekursor dalam fabrikasi sensor gas alkohol. Aplikasi lebih jauh dari sesnsor ini dapat diterapkan pada proses Halal Detection pada makanan dan minuman. Fabrication of ZnFe2O4 Based Nanoceramics plus Mn2O3 Based on Local Minerals for Alcohol Gas Sensor Applications have been successfully carried out. This study aims to optimize the mineral potential in Indonesia and determine the effect of combustion temperatures on the characteristics of nanocomposite ceramics. Semiconductor materials used are iron oxide Fe2O3 (purified by yarocytes), Mn2O3 (purified by Manganite) and ZnO. Nanocomposite powder synthesis was carried out using the precipitation method. The synthesized powder is mixed with Organic Vehicle (OV) to be made into a paste with a ratio of 70% powder: 30% OV. Fabrication of nanocomposite ceramics was carried out using a screen printing method with a burning temperature of 600 and 700 oC for two hours. Nanocomposite ceramics have cubic and hexagonal structures with a crystallite size of ~ 27 nm and 125 nm respectively for a burning temperature of 600 and 700 oC. More pores are produced at a combustion temperature of 700 °C even though with a smaller size. Where the ceramic surface is more even and has a uniform grain size. This is shown by the high sensor response performance to alcohol gas at a working temperature of 325 oC, with an alpha constant value of 1,16. Where the minimum value of a commercial sensor alpha cost is one that shows that the sensor has the potential to be produced commercially. The combustion temperature affects the pore production and the sensor response to ethanol gas. It can be concluded that local minerals have high potential and are able to compete with imported materials as a precursor in the fabrication of alcohol gas sensors. Further applications from these contributors can be applied to the Halal Detection process for food and beverages

Pengembangan Nanokeramik ZnxFe2-xO3:Mn berbahan lokal sebagai sensor alkohol bersensitivitas tinggi

Indonesia memiliki penduduk dengan mayoritas Muslim dan merupakan negara terbesar di dunia yang memiliki penduduk muslim. Syariat Islam mewajibkan kita untuk mengonsumsi makanan/minuman yang halal dan baik. Agar terjamin kebolehannya untuk dikonsumsi maka diperlukan suatu detektor. Hal ini menjadi tantangan bagi para peneliti khususnya di bidang material untuk berinovasi dalam menciptakan divais yang mampu mendeteksi kandungan gas yang terkandung dalam makanan/minuman tersebut. Sebagai contoh salah satu sampel gas yang sering terkandung dalam bahan konsumsi masyarakat adalah alkohol. Materi yang diuraikan di dalam buku ini mencakup berbagai macam metode sintesis material berukuran nano sebagai lapisan aktif yang sangat penting pada sensor gas. Teknik fabrikasi sensor yang fokus pada penggunanaan teknologi screen printing dan karakteristik sensor setelah penambahan dopan Mn dan chelating agent juga dibahas dalam buku ini. Dimana chelating agent digunakan sebagai media untuk mengikat ion-ion logam

Influence of sieve size on calorific value and proximate properties of bio-briquette composites

This work aimed to observe the influence of calorific value and proximate properties in the fabrication of rice husk (RS) and coffee shell (CH) briquettes composite. Rice and coffee husks contain cellulose, hemicellulose, and lignin. These contents are necessary for the adhesive to bind the briquette (amylose and amylopectin). The raw materials were carbonized at 400 oC for 60 minutes. Variations of sieving size (60, 80, and 100 mesh) and the composition ratio of raw material CH: RS were reviewed to study their effect. Tests of density, moisture content, volatile matter content, ash content, fixed carbon content, shatter index, combustion rate, and calorific value were carried out to determine the optimum composition. The results were obtained with the best quality at a particle size of 60 mesh with the highest calorific value of 17.422 MJ/Kg. It showed that the briquettes have good quality and are comparable with the standard briquette

Photocatalytic activity of MgFe2O4:TiO2 composite for degrading methylene blue

We reported the methylene blue (MB) degradation by the photocatalysis method. This work aimed to know the effectiveness of degradation using a MgFe2O4:TiO2 composite. Synthesis of the composite used the sol-gel method. We synthesized three samples with ratios between MgFe2O4 and TiO2. Those were 100:0, 50:50, and 75:25, respectively. Sample (75:25) degraded MB of 47.23% with a reaction rate of 5.326 x 10-3 minute-1 under solar radiation. Whereas, without solar radiation, a sample showed a lower reaction rate. It happened because the sunlight produced photon energy to produce OH* radical so that it could activate the sample to absorb the dye. Reusable test resulted 19.73% degradation of MB for 100:0, 17.03% for 50:50, and 20.59% for 75:25 for 120 minutes. The XRD result for 75:25 has three phases, which are MgFe2O4 with cubic structure, TiO2 with tetragonal structure, and Fe2O3 with hexagonal structure. This work indicated that the sol-gel method could synthesize composite structures, and the sample may be used to remove methylene blue

Influence of Sieve Size on Calorific Value and Proximate Properties of Bio-Briquette Composites

This work aimed to observe the influence of calorific value and proximate properties in the fabrication of rice husk (RH) and coffee shell (CS) briquettes composite. Rice and coffee husks contain cellulose, hemicellulose, and lignin. These contents are necessary for the adhesive to bind the briquette (amylose and amylopectin). The raw materials were carbonized at 400 °C for 60 minutes. Variations of sieving size (60, 80, and 100 mesh) and the composition ratio of raw material CS:RH were reviewed to study their effect. Tests of density, moisture content, volatile matter content, ash content, fixed carbon content, shatter index, combustion rate, and calorific value were carried out to determine the optimum composition. The results were obtained with the best quality at a particle size of 60 mesh with the highest calorific value of 17.422 MJ/kg. It showed that the briquettes have good quality and are comparable with the standard briquette

Study of Optical and Electrochemical Properties of Solvent-Dependent Natural Dye Extracted from Rivina humilis L

This work aimed to study the natural dye extracted from Indonesian wild plants (Rivina humilis L) using different solvents. The natural dye was extracted using the maceration method. Three different solvents, namely, aquades, acetone, and ethanol 96%, were used to extract natural dye from Rivina humilis L fruit. The absorbance spectra of the extracted dye were recorded using Ultraviolet-Visible (UV-Vis) spectroscopy. The different spectra of betalain pigment revealed the dye extract’s dependence on the solvent. The functional groups of the extracted dye were analyzed using FTIR spectroscopy. The adherence of carbonyl and hydroxyl groups from FTIR spectra indicated that this dye could anchor to a semiconducting material, e.g., TiO2, which was commonly used in DSSC. The electrochemical properties of the extracted pigments were studied through Higher Occupied Molecular Orbital (HOMO) and Lower Unoccupied Molecular Orbital (LUMO) energy levels. Based on the results, the best performance to construct DSSC was achieved by natural dye adsorption with aquades solvent

A global metagenomic map of urban microbiomes and antimicrobial resistance

We present a global atlas of 4,728 metagenomic samples from mass-transit systems in 60 cities over 3 years, representing the first systematic, worldwide catalog of the urban microbial ecosystem. This atlas provides an annotated, geospatial profile of microbial strains, functional characteristics, antimicrobial resistance (AMR) markers, and genetic elements, including 10,928 viruses, 1,302 bacteria, 2 archaea, and 838,532 CRISPR arrays not found in reference databases. We identified 4,246 known species of urban microorganisms and a consistent set of 31 species found in 97% of samples that were distinct from human commensal organisms. Profiles of AMR genes varied widely in type and density across cities. Cities showed distinct microbial taxonomic signatures that were driven by climate and geographic differences. These results constitute a high-resolution global metagenomic atlas that enables discovery of organisms and genes, highlights potential public health and forensic applications, and provides a culture-independent view of AMR burden in cities.Funding: the Tri-I Program in Computational Biology and Medicine (CBM) funded by NIH grant 1T32GM083937; GitHub; Philip Blood and the Extreme Science and Engineering Discovery Environment (XSEDE), supported by NSF grant number ACI-1548562 and NSF award number ACI-1445606; NASA (NNX14AH50G, NNX17AB26G), the NIH (R01AI151059, R25EB020393, R21AI129851, R35GM138152, U01DA053941); STARR Foundation (I13- 0052); LLS (MCL7001-18, LLS 9238-16, LLS-MCL7001-18); the NSF (1840275); the Bill and Melinda Gates Foundation (OPP1151054); the Alfred P. Sloan Foundation (G-2015-13964); Swiss National Science Foundation grant number 407540_167331; NIH award number UL1TR000457; the US Department of Energy Joint Genome Institute under contract number DE-AC02-05CH11231; the National Energy Research Scientific Computing Center, supported by the Office of Science of the US Department of Energy; Stockholm Health Authority grant SLL 20160933; the Institut Pasteur Korea; an NRF Korea grant (NRF-2014K1A4A7A01074645, 2017M3A9G6068246); the CONICYT Fondecyt Iniciación grants 11140666 and 11160905; Keio University Funds for Individual Research; funds from the Yamagata prefectural government and the city of Tsuruoka; JSPS KAKENHI grant number 20K10436; the bilateral AT-UA collaboration fund (WTZ:UA 02/2019; Ministry of Education and Science of Ukraine, UA:M/84-2019, M/126-2020); Kyiv Academic Univeristy; Ministry of Education and Science of Ukraine project numbers 0118U100290 and 0120U101734; Centro de Excelencia Severo Ochoa 2013–2017; the CERCA Programme / Generalitat de Catalunya; the CRG-Novartis-Africa mobility program 2016; research funds from National Cheng Kung University and the Ministry of Science and Technology; Taiwan (MOST grant number 106-2321-B-006-016); we thank all the volunteers who made sampling NYC possible, Minciencias (project no. 639677758300), CNPq (EDN - 309973/2015-5), the Open Research Fund of Key Laboratory of Advanced Theory and Application in Statistics and Data Science – MOE, ECNU, the Research Grants Council of Hong Kong through project 11215017, National Key RD Project of China (2018YFE0201603), and Shanghai Municipal Science and Technology Major Project (2017SHZDZX01) (L.S.