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Synthesis of amorphous silica from rice husk ash using the sol–gel method: Effect of alkaline and alkaline concentration

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Materials Today: Proceedings 2023年 87卷 225-229页

作者： Aprilia S. Rosnelly C.M. Zuhra Fitriani F. Haffiz Akbar E. Raqib M. Rahmah K. Amin A. Baity R.A. Department of Chemical Engineering Engineering Faculty Universitas Syiah Kuala Banda Aceh 23111 Indonesia Doctoral Program School of Engineering Post Graduate Program Universitas Syiah Kuala Banda Aceh 23111 Indonesia Mechanical Engineering Department Engineering Faculty University of Abulyatama Lampoh Keude-Aceh Besar Indonesia

In this study, silica extraction from RHA (rice husk ash) has been successfully performed by alkaline using KOH and NaOH with sol–gel precipitation. The silica gel was characterized for the functional group by FTIR, crystallinity with XRD, structure silica with SEM and particle size with PSA. The results show the higher concentration of solvent led to higher silica. The FTIR analysis revealed vibrations of Si[sbnd]O and Si[sbnd]O[sbnd]Si on the product. Additionally, observed to be amorphous and aggregated, the silica extracted from RHA also exhibited a decrease in all samples. © 2023

关键词： Alkaline extraction Concentration of solvent Potassium hydroxide Rice husk ash Silica Sodium hydroxide

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Characteristics of Lantung Fiber and the Effect of Alkali Treatment and Water Absorption on the mechanical Properties of Lantung Fiber Reinforced Composites

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Jordan Journal of mechanical and Industrial engineering 2025年第2期19卷 469-478页

作者： Hestiawan, Hendri Zuliantoni Supardi, NurulIman Sudibyo Study Program of Mechanical Engineering Faculty of Engineering University of Bengkulu Bengkulu38112 Indonesia Research Unit for Mineral Technology National Research and Innovation Agency Lampung35361 Indonesia

This study aims to investigate the effect of alkali treatment and water absorption on the mechanical properties of composites reinforced with lantung fibers. Lantung fibers were alkali-treated for one and two hours at room temperature using 4% and 6% sodium hydroxide solutions. Composite samples reinforced with lantung fibers were prepared by the hand lay-up method. The composite samples were soaked in distilled water at 60°C for 1080 hours or 45 days. All samples were subjected to tensile tests, flexural tests, and impact tests based on ASTM D638-02, D790-02, and D5942-96 standards. Alkali treatment was proven to be effective in improving the mechanical properties of lantung fiber reinforced composites. Lantung fibers soaked in 4% sodium hydroxide solution for 2 hours gave the highest mechanical properties. The initial absorption process of lantung fiber reinforced composites soaked in distilled water at 60°C was found to approach the Fickian diffusion behavior. Following an hour-long immersion in a 6% sodium hydroxide solution, lantung fibers had the lowest diffusion coefficient of 9.15x10-12 m2/s and the highest water content of 4.89%. The mechanical properties of lantung fiber reinforced composites showed insignificant decrease in impact, flexural, and tensile strength after water absorption so that lantung fiber is recommended for use in wet environmental conditions. © 2025 Jordan Journal of mechanical and Industrial engineering. All rights reserved

关键词： Tensile strength

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Effects of Wind Stresses and Progressive Waves on Surf-Zone Currents 5

Effects of Wind Stresses and Progressive Waves on Surf-Zone ...

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5th International IEEE Novel Intelligent and Leading Emerging Sciences Conference, NILES 2023

作者： Elshabrawy, Mohamed Khalid, Osama Zaki, Mamdouh Fasseh, Khaled Said, Mahmoud E. Cairo University Faculty of Engineering Giza Egypt Nile University Mechanical Engineering Program School of Engineering and Applied Sciences 12588 Egypt Giza12588 Egypt

ISBN: (纸本)9798350381030

In this paper, A numerical model based on the shallow water equations is derived to study the combined effects of wind and progressive gravity waves on surf-zone currents. The wind has temporal and spatial variations. The combined effects of spatially and temporal varying wind and waves on the surf-zone currents are investigated by considering different wave incident angles and wind stresses. Numerical results of the current distribution demonstrate the role of the basin topography, coastal configuration and the combined effect of wave radiation and wind stresses on the surf-zone currents distribution. Also, the water surface elevation emphasizes the role of the pressure gradient force due to the non-penetration condition at the coastal boundary. © 2023 IEEE.

关键词： Gravity waves

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Faster Algorithms for a Lexicographic Bi-Criteria Line Balancing Problem with Totally Ordered Precedence Constraints 13

Faster Algorithms for a Lexicographic Bi-Criteria Line Balan...

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Joint 13th International Conference on Soft Computing and Intelligent Systems and 25th International Symposium on Advanced Intelligent Systems, SCIS and ISIS 2024

作者： Imahori, Shinji Karuno, Yoshiyuki Ueda, Yuma Chuo University Faculty of Science and Engineering Tokyo Japan Kyoto Institute of Technology Faculty of Mechanical Engineering Kyoto Japan Graduate School of Science and Technology Kyoto Institute of Technology Mechanodesign Program Kyoto Japan

ISBN: (纸本)9798350373332

The line balancing has been an important production strategy which aims at redressing the balance of workloads on machines in an assembly type of production system. In this paper, a lexicographic bi-criteria optimization model of the line balancing is revisited for a mass-production of one homogeneous product. A sequence of machines and a totally ordered set of tasks are given. The machines are considered to be situated along with a production line, according to their sequence. Precedence relations between tasks are specified by the total order of tasks. The task set also consists of a given number of disjoint subsets, namely categories such that tasks in a category are considered to constitute a certain kind of family of technical skills. Each task has a positive processing time and a category index. A solution to the problem is expressed by an assignment of tasks to machines, and for the feasibility of a solution, the assignment must obey the totally ordered precedence constraint on tasks. The sum of processing times of tasks assigned to a machine in a feasible solution is the load of the machine, and the number of category indexes of tasks assigned to a machine is referred to as the degree of diverseness of the task subset. The primary objective of the problem is to minimize the maximum machine load, and the second objective is to minimize the maximum degree of diverseness of tasks assigned to a machine. The lexicographic bi-criteria line balancing problem with totally ordered precedence constraints has been known to admit a polynomial time exact algorithm, whose time complexity is linear in the number of machines and squared in the number of tasks. In this paper, a faster polynomial time exact algorithm is proposed, which improves the time complexity to be squared in the number of tasks. © 2024 IEEE.

关键词： Polynomial approximation

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Key fuel characteristics and techno-economic aspects of torrefied rubberwood biomass pellets produced by incorporating various cassava-based binders at varied doses

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Environmental Science and Pollution Research 2024年第25期31卷 37663-37680页

作者： Kongto, Pumin Palamanit, Arkom Chaiprapat, Sumate Tippayawong, Nakorn Khempila, Jarunee Ruangim, Panatda Energy Technology Program Department of Interdisciplinary Engineering Faculty of Engineering Prince of Songkla University 15 Kanjanavanich Rd. Songkhla Hat Yai90110 Thailand Research Center Faculty of Engineering Prince of Songkla University 15 Kanjanavanich Rd. Songkhla Hat Yai90110 Thailand Department of Civil and Environmental Engineering Faculty of Engineering Prince of Songkla University 15 Kanjanavanich Rd. Songkhla Hat Yai90110 Thailand Department of Mechanical Engineering Chiang Mai University 239 Huay Kaew Rd. Chiang Mai Muang District 50200 Thailand Physics Program Faculty of Science and Technology Rajabhat Maha Sarakham University 80 Nakhon Sawan Rd. Maha Sarakham Mueang District 44000 Thailand

Improving energy content and hydrophobic nature of woody biomass can be pursued through torrefaction. This gives torrefied biomass with a low bulk density, potentially increasing storage and transport costs. To overcome this issue, densifying the torrefied biomass is necessary. However, poor binding of particles makes densification challenging without using a binder. Therefore, the aim of this study was to investigate the physicochemical characteristics and techno-economic aspects of torrefied rubberwood biomass (TRWB) when pelletized using various cassava-based binders at different blending ratios. The selected binders included cassava starch (CS), cassava pulp (CP), and cassava chip (CC). Each binder at 5%, 10%, or 15% (wt.) was mixed with TRWB and water before pelletizing using a flat die machine. The results revealed that pelletizing TRWB with different cassava-based binders at various blending ratios influenced the physicochemical characteristics of the TRWB pellets, particularly dimensions, bulk density, fuel and atomic ratios, and energy content. The TRWB pellets demonstrated energy densities in the range of 7.95–11.39 GJ/m3, and their mechanical durability and fine content fell within acceptable ranges. The TRWB pellets maintained their shape during 120 min of water soaking, with water absorption levels varying by binder dose. The pelletizing ability, material, and energy costs of TRWB pellets depend on binder type and dose. CP can be applied as a binder for pelletizing torrefied rubberwood biomass. However, the mechanical durability of the product needs to be above the user requirement or standard. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.

关键词： Pelletizing

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Offsets Reconstruction Method for Clock Skew Measurement Over High-Jitter Communication

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SN Computer Science 2025年第5期6卷 1-14页

作者： Sastra, Nyoman Putra Saputra, Komang Oka Teng, Wei-Chung Study Program of Electrical Engineering Faculty of Engineering Udayana University Jalan Raya Kampus Bukit Jimbaran Bali Badung 80361 Indonesia Department of Computer Science and Information Engineering National Taiwan University of Science and Technology No. 43 Section 4 Keelung Rd Taipei 106 China

Measuring clock skew of devices over a network fully relies on the offsets, the differences between sending and receiving times. Offsets that shape a thick line are the most ideal one as their slope is directly the clock skew sought. When some outliers separate from the thick line due to higher delay jitter, current advanced approaches use the lower bound or the majority of offsets to derive accurate clock skew. However, outliers in offsets that shape parallel dotted lines, reduce the availability of offsets in the lower region, and scatter widely the offsets from their majority zone. These conditions drive the current skew estimation approaches to lose their accuracy. This paper then developed a new method, which reconstructs back the outliers into their origin positions, in order to provide ideal offsets for clock skew measurement. The experimental evaluations have demonstrated that the clock skew accuracy of dotted-lines offsets tampered by outliers was improved from 2.1 to 0.9 ppm by the proposed reconstruction method. For a broader purpose, the reconstruction method has been adjusted to be implemented also on non-dotted-lines offsets. The robustness of the proposed method for this case has also been exhibited by the very ideal reconstructed offsets that shape like a thick line. © The Author(s) 2025.

关键词： Clock skew Delay jitter Dotted lines Hough transform

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Fine and ultrafine particle- and gas-polycyclic aromatic hydrocarbons affecting southern Thailand air quality during transboundary haze and potential health effects

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Journal of Environmental Sciences 2023年第2期124卷 253-267页

作者： Napawan Mahasakpan Phatsarakorn Chaisongkaew Muanfun Inerb Nobchonnee Nim Worradorn Phairuang Surajit Tekasakul Masami Furuuchi Mitsuhiko Hata Thaniya Kaosol Perapong Tekasakul Racha Dejchanchaiwong Air Pollution and Health Effect Research Center Prince of Songkla UniversityHat YaiSongkhla 90110Thailand Energy Technology Program Faculty of EngineeringPrince of Songkla UniversityHat YaiSongkhla 90110Thailand Faculty of Environmental Management Prince of Songkla UniversityHat YaiSongkhla 90110Thailand Department of Geography Faculty of Social SciencesChiang Mai UniversityMuangChiang Mai 50200Thailand Department of Chemistry Faculty of SciencePrince of Songkla UniversityHat YaiSongkhla 90110Thailand Faculty of Geoscience and Civil Engineering Institute of Science and EngineeringKanazawa UniversityKakuma-machiKanazawaIshikawa 920-1192Japan Department of Civil and Environmental Engineering Faculty of EngineeringPrince of Songkla UniversityHat YaiSongkhla 90110Thailand Department of Mechanical and Mechatronics Engineering Faculty of EngineeringPrince of Songkla UniversityHat YaiSongkhla 90110Thailand Department of Chemical Engineering Faculty of EngineeringPrince of Songkla UniversityHat YaiSongkhla 90110Thailand

Distribution of PM_(0.1),PM_(1) and PM_(2.5) particle-and gas-polycyclic aromatic hydrocarbons(PAHs)during the 2019 normal,partial and strong haze periods at a background location in southern Thailand were investigated to understand the behaviors and carcinogenic ***1 was the predominant component,during partial and strong haze periods,accounting for 45.1% and 52.9% of total suspended particulate matter,respectively,while during normal period the contribution was only 34.0%.PM_(0.1) concentrations,during the strong haze period,were approximately 2 times higher than those during the normal *** increased levels of particle-PAHs for PM_(0.1),PM_(1) and PM_(2.5) were observed during strong haze period,about 3,5 and 6 times higher than those during normal ***-PAH concentrations were 10 to 36 times higher than those of particle-PAHs for PM_(2.5).Average total Benzo[a]Pyrene Toxic Equivalency Quotients(BaP-TEQ)in PM_(0.1),PM_(1) and PM_(2.5) during haze periodswere about 2–6 times higher than in the normal *** total accumulated Incremental Lifetime Cancer Risks(ILCRs)in PM_(0.1),PM_(1) and PM_(2.5) for all the age-specific groups during the haze effected scenario were approximately 1.5 times higher than those in nonhaze scenario,indicating a higher potential carcinogenic *** observations suggest PM_(0.1),PM_(1) and PM_(2.5) were the significant sources of carcinogenic aerosols and were significantly affected by transboundary haze from peatland *** leads to an increase in the volume of smoke aerosol,exerting a significant impact on air quality in southern Thailand,as well as many other countries in lower southeast Asia.

关键词： Particle-PAH Gas-PAH Ultrafine particle Health risk Source identification

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Enhanced Dye Adsorption and Bacterial Removal of Magnetic Nanoparticle-Functionalized Bacterial Cellulose Acetate Membranes

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Journal of Renewable Materials 2024年第9期12卷 1605-1624页

作者： Heru Suryanto Daimon Syukri Fredy Kurniawan Uun Yanuhar Joseph Selvi Binoj Sahrul Efendi Fajar Nusantara Jibril Maulana Nico Rahman Caesar Komarudin Komarudin Centre of Advanced Material for Renewable Energy(CAMRY) Universitas Negeri MalangMalang65145Indonesia Department of Mechanical and Industrial Engineering Universitas Negeri MalangMalang65145Indonesia Department of Food and Agricultural Product Technology Faculty of Agricultural TechnologyAndalas UniversityPadang25163Indonesia Department of Chemistry Institut Teknologi Sepuluh NopemberSurabaya60111Indonesia Study Program of Aquatic Resources Management Faculty of Fisheries and Marine ScienceBrawijaya UniversityMalang65145Indonesia Institute of Mechanical Engineering Saveetha School of EngineeringSaveetha Institute of Medical and Technical Sciences(SIMATS)Saveetha UniversityChennai602105India Faculty of Vocational Universitas Negeri MalangMalang65145Indonesia

Utilizing biomass waste as a potential resource for cellulose production holds promise in mitigating environmental *** current study aims to utilize pineapple biowaste extract in producing bacterial cellulose acetate-based membranes with magnetic nanoparticles(Fe_(3)O_(4)nanoparticles)through the fermentation and esterification process and explore its *** bacterial cellulose fibrillation used a high-pressure homogenization procedure,and membranes were developed incorporating 0.25,0.50,0.75,and 1.0 wt.%of Fe3O4 nanoparticles as magnetic nanoparticle for *** membrane characteristics were measured in terms of Scanning Electron Microscope,X-ray diffraction,Fourier Transform Infrared,Vibrating Sample Magnetometer,antibacterial activity,bacterial adhesion and dye adsorption *** results indicated that the surface morphology of membrane changes where the bacterial cellulose acetate surface looks *** crystallinity index of membrane increased from 54.34%to 68.33%,and the functional groups analysis revealed that multiple peak shifts indicated alterations in membrane functional ***,adding Fe_(3)O_(4)-NPs into membrane exhibits paramagnetic behavior,increases tensile strength to 73%,enhances activity against *** and ***,and is successful in removing bacteria from wastewater of the river to 67.4%and increases adsorption for anionic dyes like Congo Red and Acid Orange.

关键词： Bacterial cellulose dye adsorption Fe_(3)O_(4)nanoparticles membrane pineapple waste

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The tensile and flexural forces of acropora reef waste particulate-enchanced polyester composites 6th

The tensile and flexural forces of acropora reef waste parti...

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6th International Conference on Building Materials and Construction, ICBMC 2021, Nanotechnology and Nanomaterials in Energy, ICNNE 2021, and Energy engineering and Smart Materials, ICEESM 2021

作者： Pamungkas, Akmal Raka Surata, I. Wayan Nindhia, Tjokorda Gde Tirta Master Student at Study Program of Master in Mechanical Engineering Engineering Faculty Udayana University Denpasar Bali Indonesia Study Program of Mechanical Engineering Faculty of Engineering Udayana University Jimbaran Bali Indonesia

ISBN: (纸本)9783035718928

Composite is a material that combines two or more materials that basically dissimilar chemical or physical properties from one another. In this research, we used Acropora coral reef waste particulate and Resin Polyester BQTN type 157 with Methyl ethyl ketone peroxide (MEKP) 1% as the hardener. The Hand Lay-Up molding technique is used in the process of making the material. The tensile and flexure test is done according to the ASTM D3090 and ASTM D790 – 03 standards. The purpose of this research is to discover the means to produce a composite enhanced by Acropora coral reef waste with polyester matrix and to learn the tensile and flexure strength from the Acropora coral reef waste particulate-enhanced polyester composites with mass fraction varieties of 10%, 20%, 30%, and 40%. The tensile test result of Acroporal coral reef waste particulate with polyester matrix yields average tensile strength at mass fraction variety of 40% with a score of 19,66 MPa, with an Modulus score of 636,75 MPa. The flexure test result of Acropora coral reef waste particulate with polyester matrix yields average flexure stress at mass fraction variety of 40% with a score of 112,56 MPa, with an average Elastic Modulus score of 3098,96 MPa. © 2021 Trans Tech Publications Ltd, Switzerland.

关键词： Polyester resins

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Removing or Avoiding the Camera Focus Light Appearing on Glossy or Bouncing Surfaces by Light Guiding and Image Warping 22

Removing or Avoiding the Camera Focus Light Appearing on Glo...

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4th International Conference on Information Technology and Computer Communications, ITCC 2022

作者： Rompis, Lianly Electrical Engineering Study Program Faculty of Engineering Universitas Katolik de la Salle Manado Indonesia

ISBN: (纸本)9781450396820

Digital picture or image becomes more and more important in people's daily life, such as for administration, documentation, active communications, and learning processes. People also demand the exchange of information through digital applications and social media. Taking picture or photo of a document, book, certificate, or thing is usually done by the help of digital scanner, but not all these stuffs can be converted into digital with a scanner. In specific condition people need real image transfer and will take photo of the real view directly using their own digital camera or smartphone camera. From author experience and observations, when taking photos of a document or book or certificate or thing normally with plastic cover or glass surface or bouncing surface, we clearly got an annoying light came from the camera focus light or flash that usually creates noise and messy image. This research was conducted based on the idea to remove or avoid getting the unwanted or disturbing light while taking photos of glossy or bouncing surfaces. A procedure to get a clear and smooth image instead of noise and broken image was derived and implemented by author using light guiding and image warping. These two methods bring accurate images that are necessary for communication needs and facilitate better future works without compromising security policies and people's rights. As the research methodology, author performed literature study, observation, analysis, and implementation. The result of this research offers a good procedure and method that can help people getting clear photos or pictures of a glossy or bouncing surface, advance research to be implemented related to camera technology, and best comprehension to improve photography techniques for future developments. © 2022 ACM.

关键词： Image enhancement

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