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Selective surface functionalization at regions of high local curvature in graphene

chemical Communications 2013年第7期49卷 677-679页

作者： Wu, Qingzhi Wu, Yaping Hao, Yufeng Geng, Jianxin Charlton, Matthew Chen, Shanshan Ren, Yujie Ji, Hengxing Li, Huifeng Boukhvalov, Danil W. Piner, Richard D. Bielawski, Christopher W. Ruoff, Rodney S. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Biomedical Materials and Engineering Center Wuhan University of Technology Wuhan 430070 China Department of Mechanical Engineering Department of Materials Science Department of Engineering Program The University of Texas at Austin Austin TX 78712 1 University Station C2200 United States Department of Chemistry and Biochemistry The University of Texas at Austin Austin TX 78712 1 University Station A1590 United States School of Computational Sciences Korea Institute for Advanced Study Seoul 130-722 South Korea ) School of Chemical and Biological Engineering Seoul National University Seoul 151-742 South Korea

Monolayer graphene was deposited on a Si wafer substrate decorated with SiO2 nanoparticles (NPs) and then exposed to aryl radicals that were generated in situ from their diazonium precursors. Using micro-Raman mapping...

Monolayer graphene was deposited on a Si wafer substrate decorated with SiO₂ nanoparticles (NPs) and then exposed to aryl radicals that were generated in situ from their diazonium precursors. Using micro-Raman mapping, the aryl radicals were found to selectively react with the regions of graphene that covered the NPs. The enhanced chemical reactivity was attributed to the increased strain energy induced by the local mechanical deformation of the graphene. © The Royal Society of Chemistry.

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Application of Response Surface Methodology for Biodiesel Synthesis Optimization Through Transesterification Reaction using h-zeolite/ki Heterogeneous Catalyst

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IOP Conference Series: Materials Science and engineering 2019年第1期536卷

作者： E Kurniasih P Pardi Department of Chemical Engineering Study Program of Industrial Chemical Technology Politeknik Negeri Lhokseumawe Aceh Departement of Chemical Engineering Study Program of Oil and Gas Production Politeknik Negeri Lhokseumawe Aceh

Biodiesel production based on crude palm oil (CPO) using heterogeneous catalysts is a new hope for solving the energy crisis. One type of heterogeneous catalyst is H-Zeolite/KI synthesized from natural zeolite impregnated with 0.05% (w/v) KI compound for 2 hours. The research focuses on determining the optimum operating conditions for biodiesel production using H-zeolite/KI catalysts. As raw material used CPO which has pre-treatment through an esterification reaction using 15% H2SO4 (w/v) as catalyst, temperature 65°C, stirrer speed of 400 rpm for 2 hours to reduce the free fatty acid content of raw materials up to 40%. Optimization of biodiesel production is carried out at the transesterification reaction. The research data was designed following the Response Surface Methodology (RSM) method using 3 independent variables and 5 levels, namely the ratio of H-zeolite/KI catalyst, transesterification temperature and mole methanol: CPO ratio with coded level (-1.682), (-1), (0), (+1), (+1.682). The research results show that the optimum operating conditions of biodiesel production were at the ratio of H-zeolite/KI catalyst at 2% - 2.5% (w/w), temperature at 45°C-50°C and mole ratio of methanol: CPO at (1:6). The biodiesel product was confirmed using gas chromatography and showed ester content of 88.02%. Characteristics of biodiesel products showed flash point 130C, acid number 0.4%, glycerol free 0%, viscosity 3.6 cP, density0.879 gr/cm3.

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Transesterification Condition of Crude Palm Oil to Biodiesel Using Solid Catalyst Zeolite/NaOH

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IOP Conference Series: Materials Science and engineering 2020年第1期854卷

作者： E Kurniasih P Pardi Adriana Department of Chemical Engineering Study Program of Industrial Chemical Technology Polytechnic State of Lhokseumawe Aceh Department of Chemical Engineering Study Program of Oil and Gas Production Polytechnic State of Lhokseumawe Aceh

The use of NaOH as a catalyst for biodiesel production has long been used and provides high conversion conversions. Homogeneous NaOH phase during the transesterification reaction causes soap to form at the end of the process. Soap is diseparasi from biodiesel by washing and decantation techniques. The presence of soap can reduce the quality of biodiesel, especially at the flash point of biodiesel. Heterogeneous catalyst zeolite / NaOH is synthesized from natural zeolite and NaOH through the impregnation method. Natural zeolite is contained in natural rock obtained from Ujong Pancu, Aceh Besar. The synthesis of natural zeolite catalyst was initiated by activating zeolite powder with 4 M HCl for 10 hours at 90oC. Activated zeolite was impregnated using 2.5% NaOH at a ratio of 1: 2 (w / v) at 90oC for 2 hours. Application of zeolite / NaOH in transesterification reaction using crude palm oil off grade. The results showed that the use of zeolite / NaOH can prevent the formation of soap with characteristics that have met SNI 04-7182-2006 standards.

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Estimating the opportunities of ester content improvement through variation of NaOH, KI And KIO3 developed impregnators on activated natural zeolite catalyst for methyl ester synthesis

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IOP Conference Series: Materials Science and engineering 2020年第1期725卷

作者： E Kurniasih P Pardi Departement of Chemical Engineering Study Program of Industrial Chemical Technology Polytechnic State of Lhokseumawe Aceh Departement of Chemical Engineering Study Program of Oil and Gas Production Polytechnic State of Lhokseumawe Aceh

The Content of esters are the number of compositions of esters formed after the esterification and / or when transesterification reaction takes place. Esters are formed by breaking up the alkyl acid carboxylic group of fatty acids or triglycerides which react with methyl groups from methanol. To increase the reaction rate, heterogeneous catalysts were synthesized using impregnators NaOH, KI and KIO3. The impregnator is carried out in the framework of natural zeolite with a concentration of 2.5% (w/v). The zeolite framework was previously activated using 6M HCl solution for 10 hours at a temperature of 90°C. To strengthen the impregnator bond on a heterogeneous zeolite catalyst, calcination was carried out at a temperature of 600°C for 4 hours. Heterogeneous catalysts were tested on biodiesel production using a transesterification reaction. The transesterification reaction was carried out at a temperature of 65°C for 2 hours based on crude ester with 5%-10% (w/w) heterogeneous zeolite catalyst ratio shows the percentage decrease in free fatty acid content of 74.05% for zeolite/NaOH, 75.01% for zeolite/KIO3 and 75.77% for zeolite/KI. Based on the results of gas chromatography analysis, it was found that zeolite/KI catalysts of 77.1591.86%.

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Analysis of process variables on biodiesel transesterification reaction using Taguchi Method

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IOP Conference Series: Materials Science and engineering 2018年第1期420卷

Continuous process for biodiesel production using homogeneous catalysts finds many constraints. Heterogeneous catalysts are the solution for the production of continuous biodiesel. One of the heterogeneous catalysts is zeolite/KIO3. Determination of operating conditions for heterogeneous catalysts, especiallyzeolite/KIO3 is required to obtain appropriate process conditions in order to the continuous system. The Taguchi method is one of experimental design that focuses on the variable approach to product quality improvement by control operation condition. Taguchi method is designed using 4 independent variables with 2 levels (4x2), which are temperature, mole ratio, time reaction and heterogeneous catalyst ratio. The Taguchi method can provide an analysis of the influence of each process variable significantly. This study aims to determine optimal operating conditions for the production of biodiesel with the KIO3 heterogeneous catalyst. Biodiesel is synthesized by esterification (pre-treatment) and transesterification following the Taguchi method. The source of triglyceride is crude palm oil while the alkyl source comes from methanol. Based on the result of analysis Taguchi method known that all process variables have an effect to transesterification reaction. But, variable temperature and reactant mole ratio give the most significant influence and show the interaction with p-value value 0.000 (temperature) and p-value 0.001(reactant mole ratio).Thus, for the production of biodiesel using the KIO3 heterogeneous catalyst obtained optimal operation conditions at temperature 65°C, mole ratio 1:6, time reaction 120 minutes and heterogeneous catalyst ratio at 5% (w/w). ANOVA gave result decided to reject Ho, and decided the reaction model influence by the variable process.

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Hydrolysis of sorghum starch to glucose using organic acid catalyst from rosella flower extract (Hibiscus sabdariffa L.)

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IOP Conference Series: Materials Science and engineering 2020年第1期959卷

作者： Riniati S H Abdulloh R H Fauziyah Istiqomaturohmah Chemical Analysis Study Program Chemical Engineering Department Politeknik Negeri Bandung Indonesia

Highly starch content in sorghum seed has a high potential raw material for the sorghum fluor to be a raw material of liquid sugar known as glucose syrup. The syrup is usually produced through enzymatically or chemically hydrolysis using a strong acid. In this study, sorghum starch is hydrolyzed chemically using a catalyst of organic acids extracted from roselle flower (Hibiscus sabdariffa L.). The goal of the study is to produce glucose syrup free from chemical agents so as generally recognized as safe (GRAS). Rosella flowers are known to contain high amounts of organic acids such as citric acid, malic acid, tartaric acid, oxalic acid, and hibiscus acid. Apart from having natural acid content, rosella flowers also contain vitamins (ascorbic acid) and are rich in natural red pigment dyes from the anthocyanins that can be an added value for the glucose syrup products. Organic acid extraction of dried rosella flowers was carried out at a temperature of 100°C for 30 minutes in a water bath and filtered. The resulting acid extract then determined the value of the total titrated acid (TTA) by the acid-base titration method. Sorghum starch is prepared by mixing sorghum flour with distilled water and then cooled at 4°C for 12 hours. Starch is obtained from the dried filtrate to obtain a water content of <14%. The starch hydrolysis process with rosella flower extract was carried out in several variations, namely the hydrolysis time of 1 - 4 hours, the TTA concentration of rosella 4 - 16%. Meanwhile, the temperature and stirring speed were fixed at 96°C and 200 rpm. The resulting glucose levels were analyzed by the spectrophotometric method. From this research, the result shows that the best sorghum starch hydrolysis condition was obtained at the addition of 16% acid extract for 180 minutes which gave 13.83% of glucose yield

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Retraction notice to "Pyrolysis: An effective technique for degradation of COVID-19 medical wastes" [Chemosphere 275 (2021) 130092]

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Chemosphere 2025年 370卷 143824页

作者： Selvakumar Dharmaraj Veeramuthu Ashokkumar Rajesh Pandiyan Heli Siti Halimatul Munawaroh Kit Wayne Chew Wei-Hsin Chen Chawalit Ngamcharussrivichai (Deemed to be University) Chennai 603112 Tamil Nadu India. Center of Excellence in Catalysis for Bioenergy and Renewable Chemicals (CBRC) Faculty of Science Chulalongkorn University Bangkok 10330 Thailand. Department of Biochemistry Karpagam Academy of Higher Education (formerly Karpagam University) Pollachi Main Road Eachanari Post Coimbatore Tamil Nadu India. Chemistry Study Program Department of Chemistry Education Faculty of Mathematics and Science Education Universitas Pendidikan Indonesia Jl. Dr. Setiabudhi 229 Bandung 40154 Indonesia. School of Energy and Chemical Engineering Xiamen University Malaysia Jalan Sunsuria Bandar Sunsuria 43900 Sepang Selangor Malaysia College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 Fujian China. Department of Aeronautics and Astronautics National Cheng Kung University Tainan 701 Taiwan Research Center for Smart Sustainable Circular Economy Tunghai University Taichung 407 Taiwan Department of Mechanical Engineering National Chin-Yi University of Technology Taichung 411 Taiwan. Center of Excellence in Catalysis for Bioenergy and Renewable Chemicals (CBRC) Faculty of Science Chulalongkorn University Bangkok 10330 Thailand Center of Excellence on Petrochemical and Materials Technology (PETROMAT) Chulalongkorn University Pathumwan Bangkok 10330 Thailand.

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Effect of sugar on nutrient composition and shelf life of red guava jams 2

Effect of sugar on nutrient composition and shelf life of re...

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2nd International Conference on Life and Applied Sciences for Sustainable Rural Development, ICLAS-SURE 2019

作者： Nissa, Choirun Arifan, Fahmi Febrianto, Rico Aditya, William Hayu Dwimawanti, Ida Pramudyono Widyasmara, Reyno Nutrition Department Faculty of Medicine Diponegoro University Jl. Prof Soedharto Tembalang Semarang50239 Indonesia Chemical Engineering Department DiponegoroUniversity Jl. Prof Soedharto Tembalang Semarang50239 Indonesia Public Administration Department DiponegoroUniversity Jl. Prof Soedharto Tembalang Semarang50239 Indonesia Publik Health Study Program Hakli College of Health Sciences Jl. Dr. Ismangil No.27 Bongsari Semarang Indonesia

Red guava as fruit jams normally preserved using added sugar to prolong its shelf life. Heating process and different sugar content could affect in nutrient content and expiration date. Hence, the aim of this study was to evaluate the nutrient content and shelf life of jams based on two different sugar content. Two hundred (jam A) and two hundred and fifty grams of sugar (jam B) was added in 800 grams of guava then cooked at 70°C within an hour. Protein and fat was measured using Kjeldahl and soxhlet, while water and ash content was analyzed using thermogravimetry and dry ash method. Carbohydrate was calculated using by difference method. Shelf life determination was obtained using organoleptic test, containing taste, aroma, and visual sensory. In result, jam A have a higher protein (0.334%), fat (1.567%), and water (29.21%) than jam B (0.306%;1.092%;27.32%). On the other hand, ash (0.34%) and carbohydrate (68.549%) in jam A are lower than B (0.37% and 70.912 respectively). Overall, jam A have a higher protein, fat, water and carbohydrate content than jam B. A higher water content potentially indicate a lower shelf life which seen in jam A. In conclution, terms of nutritional composition, jam A have higher content than jam B, but have lower shelf life. © Published under licence by IOP Publishing Ltd.

关键词： Nutrition

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Design of mutation-resistant HIV protease inhibitors with the substrate envelope hypothesis (vol 69, pg 298, 2007)

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chemical BIOLOGY & DRUG DESIGN 2007年第6期69卷 455-455页

作者： Chellappan, S. Center for Advanced Research in Biotechnology University of Maryland Biotechnology Institute 9600 Gudelsky Drive Rockville MD 20850 USA Chemical Biology Program Department of Biochemistry and Molecular Pharmacology University of Massachusetts Medical School Worcester MA 01605 USA Department of Biochemistry and Molecular Pharmacology University of Massachusetts Medical School Worcester MA 01605 USA Department of Chemistry Massachusetts Institute of Technology Cambridge MA 02139 USA Biological Engineering Division Department of Electrical Engineering & Computer Science Massachusetts Institute of Technology Cambridge MA 02139 USA *Correspondence: Michael K. Gilson *Correspondence: * Michael K. Gilson gilson@umbi.umd.edu http://gilsonlab.umbi.umd.edu[?][?]These authors contributed equally to this study.

There is a clinical need for HIV protease inhibitors that can evade resistance mutations. One possible approach to designing such inhibitors relies upon the crystallographic observation that the substrates of HIV protease occupy a rather constant region within the binding site. In particular, it has been hypothesized that inhibitors which lie within this region will tend to resist clinically relevant mutations. The present study offers the first prospective evaluation of this hypothesis, via computational design of inhibitors predicted to conform to the substrate envelope, followed by synthesis and evaluation against wild-type and mutant proteases, as well as structural studies of complexes of the designed inhibitors with HIV protease. The results support the utility of the substrate envelope hypothesis as a guide to the design of robust protease inhibitors.

关键词： AIDS crystal drug design inhibitor protease

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Solid-state fermentation with variation of inoculum volume in mold to increase the content of alpinetin in rice bran oil

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AIP Conference Proceedings 2024年第1期2710卷

作者： Muhammad Reynaldy Syamsurridjal Tania Surya Utami Rita Arbianti Bioprocess Engineering Study Program Department of Chemical Engineering Universitas Indonesia Depok Indonesia

Alpinetin (7-hydroxy-5-methoxyflavanone) is a flavonoid with anti-bacterial, anti-inflammatory, and other important therapeutic effects, so it has significant potential benefits. Rice husks or bran from rice are known to contain antioxidants, one of which is flavonoids. The addition of mold in the fermentation process can be used to enrich the lipid content of the fermented bran. Therefore, Aspergillus terreus chose as a mold. In this study, the fermentation process varied in the volume of mold inoculum with variables 1, 3, 5, 7, and 9 mL in the fermentation medium, respectively. Inoculum volume variables are related to the metabolic products of the mold used, Aspergillus terreus, where the metabolic products in the form of desaturase and elongase enzymes catalyze the formation of unsaturated fatty acids. This unsaturated fatty acid content was tested qualitatively using LC-MS/MS-TQF. The results showed that the volume of inoculum with a variation of 7 mL had the highest lipid yield of 19.94% and with the detection of alpinetin content in RT 13.04 with an area (%) of 31.03%.

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