bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effectiveness of School Safe Zones on Taman Siswa Street, Sekaran, Gunungpati District, Semarang City
Authors: Sholahudin Farhan , Haryadi Bambang
Published: October 2024

The installation of School Safe Zones on Taman Siswa Street is considered suboptimal, given that many road users still travel at high speeds and pedestrians, especially students, teachers, and the surrounding community, have not utilized the School Safe Zones facilities. The purpose of this study is to determine the effectiveness of School Safe Zones on Taman Siswa Street, particularly in the school areas of SD N Sekaran 1 and SD N Sekaran 2. The urgency of this research is to evaluate the installation of School Safe Zones on Taman Siswa Street, especially in the school areas of SD N Sekaran 1 and SD N Sekaran 2. The approach taken includes surveys of vehicle speed, pedestrian behavior, drop-off behavior, and road equipment facilities. The results of this study are expected to benefit road users, particularly pedestrians in the school areas, by enhancing safety and security when walking and crossing the street. Based on the analysis results, it can be concluded that the effectiveness at both School Safe Zones locations is still inadequate, as many students are crossing improperly, and the behavior of escorts is also not ideal. Additionally, road users are still driving at high speeds despite the presence of School Safe Zones signage.
Advancing Green Technology Systems through Digital Economy Innovations: A Study on Sustainable
Authors: Eshbayev Oybek , Xursandov Komiljon , Pulatovna Khaydarova Umida , Sitora Amirdjanova , Jamalova Gulnoza
Published: October 2024

This study examines the intersection of green technology systems and digital economy innovations to promote sustainable development. The primary objective is to understand how digital innovations enhance the effectiveness of green technologies and their impact on sustainability. Utilizing a cross-sectional dataset, we conducted an ANOVA analysis to evaluate the relationship between digital innovations and various green technology applications across different sectors, including renewable energy, sustainable agriculture, and waste management. Our findings reveal significant positive impacts of digital innovations on the performance and adoption of green technologies. In renewable energy, smart grids and blockchain for energy trading have led to improved energy management and efficiency. In sustainable agriculture, IoT-based precision farming and AI-driven crop monitoring have resulted in increased productivity and resource optimization. In waste management, digital platforms and AI for waste sorting have enhanced recycling rates and waste monitoring. The analysis identifies key challenges such as technological integration, economic barriers, and regulatory issues, but also highlights numerous opportunities for growth, particularly in policy development and collaborative efforts between governments, businesses, and the tech industry. The study underscores the critical role of digital transformation in driving sustainable practices and offers policy recommendations to support the integration of digital and green technologies. In conclusion, this research demonstrates that digital economy innovations significantly contribute to the advancement of green technology systems, promoting sustainable development and offering a pathway for future growth and environmental stewardship. The findings are significant for policymakers, industry leaders, and researchers aiming to foster sustainable development through technological innovation.
The Effect of Tidal Influence on the Palingkau Swamp Irrigation Area SP1, SP2, SP3
Authors: Lesmono Brama , Jayadi Rachmad , Rahardjo Adam Pamuji
Published: October 2024

Water supply and drainage in the Palingkau Swamp Irrigation Area, Kapuas Regency, Central Kalimantan Province, is affected by the tides of the Kapuas and Kapuas Murung Rivers as water sources. The flow reach into the irrigation area depends on the tidal flow energy. Insufficient flow energy can lead to dead water zones in several channels, as water cannot be discharged into the handil outlets. This study aims to assess the location of potential occurrence of water dead zones through hydraulic simulations based on channel geometry and the observed tidal water levels at two locations simultaneously. The hourly water level data was recorded simultaneously using CCTV at two points for 14 days. Unsteady flow simulations were modeled using the HEC-RAS application to determine the dominant influence of the tidal water sources and the presence of dead water zones. The simulation results indicate that the tidal influence on the Palingkau Swamp Irrigation Area is more dominant from the Kapuas River. The tidal amplitudes of the Kapuas River and the Kapuas Murung River are 2.18m and 1.38m respectively. Several water dead zones were found in collector channels, requiring efforts to enhance water management through more detailed hydraulics modeling.
Liquefaction potential and severity analysis on road embankment in Serang-Panimbang Toll Road Section 3
Authors: Priyanto Nur , Faris Fikri , Setiawan Hendy
Published: October 2024

The Serang-Panimbang Toll Road is one of the national strategic projects. The project location is in proximity to several seismic activity zones, including the Son of Mount Krakatoa, Labuhan Fault, Ujung Kulon Faults, and Sunda Megathrust. A liquefaction analysis is essential to identify areas with high liquefaction potential and to evaluate the embankment road’s ability to withstand liquefaction events. This analysis is conducted using the Simplified Method based on borehole data. Subsequently, the Liquefaction Potential Index (LPI) and Liquefaction Severity Index (LSI) are employed to determine the potential level and severity of liquefaction. The analysis results indicate that the section from STA 59+950 to 60+750 exhibits high to very high LPI values but only low to moderate LSI values. Further evaluation of the road embankment’s stability under liquefaction conditions is necessary to ensure the Serang-Panimbang toll road network remains operational during significant seismic events.
Techno Economy Evaluation of Co-firing Method with CFBB Boiler Type in Indonesia
Authors: Shamad A.M Akmal Abdus , Yusran Yusran , Suyuti Ansar
Published: October 2024

Studies on the use of biomass focus on its effectiveness in producing efficient and clean energy production. Using two treatments, this research tested the joint combustion of coal and biomass in a circulating fluidized type boiler (CFBB). The parameters tested are divided into technical evaluations, namely the performance of the generator and the emissions produced. In contrast, the cost evaluation is an economic study of the co-firing method. The application of co-firing at both plants produces a good efficiency level, as indicated by the generator performance and emissions, as shown by a reduction in SO2 emissions by -33.8% in plant A. The co-firing method in plant A produces a higher heating value. In contrast, plant B produces a higher level of energy consumption. In the environmental aspect, co-firing in the two plants under review produces better emissions using the co-firing method. Plant B’s emission efficiency level is better than that of plant A. With a decrease in CO of 77% in plant A. In terms of economy, adding biomass in the co-firing method shows a reduction in costs in plant A by 0.35% and an increase in the expenses in plant B.
A Critical Review on Tropical Fruits Peels as Eco Enzyme: A Case of Indonesian Exotic Fruits
Authors: Damayanti Astrilia , Winaningsih Ima , Bahlwan Zuhriyan Ash Shiddieqy , Widyastuti Catur Rini , Auralita Kakalia Putri , Enjelita Anggun , Alfareza Xuanzie
Published: October 2024

Indonesia has a tropical climate rich in exotic fruits, such as pineapples, bananas, oranges, papaya, mangoes, watermelons, and pomegranates. Apart from its abundant production, these fruits also have parts of the fruit that are rarely used, such as seeds and peels. The peel of exotic fruits can be used as an eco-enzyme because of its enzyme content. Eco-enzymes are a type of natural compound that can usually be extracted from fruit peel or waste. Eco-enzymes are vinegar made by fermenting food waste with sugar to form alcohol. This review focuses on the potential use of exotic fruit peels and the enzymes they contain, which are used as ecoenzymes. Eco-enzyme production reduces the accumulation of organic waste and has several other benefits, including cleaning floors, equipment, etc. Extensive research in the industrial sector must also be carried out to improve the nutritional and functional potential of the peel of this exotic fruit.
Performance Evaluation of Hydrostatic Transmission Systems in Tidal Energy Conversion
Authors: Handoko Catur Rakhmad , Mukhtasor Mukhtasor , Koenhardono Eddy Setyo
Published: October 2024

The growing need for renewable energy has brought oceancurrent energy’s promise as a consistent and ecologically benign source front stage. One can effectively harness this energy with tidal energy conversion systems (TECS). This work examined the performance of a hydrostatic transmission (HST) system in a prototype tidal stream power producing configuration. Comprising a turbine simulator, hydraulic transmission, and permanent magnet synchronous generator (PMSG) with torque, power, and speed sensors, the experimental setup Under different torque settings, tests were performed to assess if the system could separate submerged components from those above sea level and improve rotational speed. According to the findings, the HST system has rather poor efficiency, averaging about 22%, even as it delivers the intended speed gain. Efficiency loss results from elements including hydraulic fluid viscosity, internal wear, and shaft alignment. These results highlight the need of more study to maximize HST systems for improved dependability and performance in tidal energy uses.
Rapid Assessment of Effectiveness Pump Storage Power Plant of Jatiluhur Reservoir
Authors: Nurkhaerani Fatma , Nugroho Eka Oktariyanto , Utami Dian Kurnia , Suryadi Cahya , Sugiarto Amalia Rizka , Mardiyono Anton , Rachmadyanto Herry
Published: October 2024

The reliable discharge calculation for forecasting discharge entering the Jatiluhur Reservoir uses the Thomas Fierring method. In this study, a rapid assessment was carried out on the effectiveness of the PSPP in the Jatiluhur Reservoir in 2040 by also considering changes in water demand downstream of Jatiluhur in 2040. A pumped storage power plant (PSPP) is a renewable energy storage medium for electrical energy. A rapid assessment was carried out on the calculation of the energy and volume produced with the operational hours, the condition of the reservoir being full (+ 106.5 m) and the condition of the reservoir approaching the minimum operating limit (+ 90 m). Based on the study’s results, PSPP at the Jatiluhur Reservoir will produce additional electrical energy of 2,180,763 kWh with a water volume requirement of 6,669,000 m3/day and operational is 2,85 hours. The operational of PSPP will reduce the Water High Level (WHL) of the Jatiluhur Reservoir by 0.12 m (full-time condition) and 0.15 m (minimum operating limit reservoir condition). With the PSPP, it is known that the Jatiluhur Reservoir can still operate normally so that the PSPP can increase electricity production without significantly reducing the WHL and volume of the Jatiluhur Reservoir.
Review: Production Mechanism of Yogurt with Additional Plant-Based High Protein for Vegetarian Consumers
Authors: Damayanti Astrillia , Bahlawan Zuhriyan Ash Shiddieqy , Fibriana Fidia , Kayati Fitri Nur
Published: October 2024

The world of the food industry is increasingly experiencing the development of various food products, but few products still avoid the emergence of cardiovascular diseases. So, many people are starting to adopt a healthy lifestyle by reducing the consumption of animal products and switching to plant-based products. The development of plant-based Yogurt not only provides healthier choices but also meets the needs of consumers who have special preferences or dietary needs. In addition to being low in fat, this Yogurt can be enriched with additional nutrients such as fiber, vegetable protein, and vitamins, which further increase its nutritional value. With the increasing awareness of healthy and environmentally friendly diets, plant-based Yogurt can be an attractive option for many consumers. The potential of high-protein plant-based Yogurt in Indonesia is quite large, considering the availability of ingredients such as ketapang seeds (Terminalia catappa), yellow pumpkin seeds (Cucurbita moschata), or chia seeds (Salvia hispanica) can be used as an addition in Yogurt to add texture and nutrient content such as protein, fiber, and omega-3 fatty acids.
SteFib ECC Built a Resilience Infrastructure
Authors: Rahman Nurharniza Abdul , Hamzah Siti Hawa , Maat Amirullah , Foo Chow Yee , Mohd Zulkifli Intan Syaqirah , Rahman Bashirulhafi Abdul , Cionita Tezara , Malek Norjihan , Gunesegeran Kishan , Pin Lee Hoong , Pei Low Wen
Published: October 2024

Sustainable Development Goals (SDG) 9 calls for resilient infrastructure, promote inclusive and sustainable industrialisation and foster innovation. Echoing this vision, construction industries have prioritised resilient structure and sustainable design while optimising economic and wealth growth. The use of steel fibre (SteFib) as scattered reinforcement in building design and construction had been explored. SteFib has been designed as reinforcement in the structural components of the building namely, raft foundation, floor and roof slabs, wall panel and column. Prototype of an Industrialised Building System (IBS) with two (2) bedrooms, one (1) living area and linked to a small kitchen was constructed using hook ended SteFib, 60 mm long and 0.7 mm in diameter mixed in grade 40 concrete. The prototype has successfully proven that the SteFib is able to stand as fully reinforced structure through this tiny home project. The structural performance analysed and verified using Autodesk Robot Structural Analysis. The analysis results show that steel fibre house has higher stress, forces and moment compared with normal concrete house.
Synthesis and Characterization of Cellulose Acetate from Oil Palm Empty Fruit Bunches (OPEFB) as Membrane Material
Authors: Fauziyyah Agnès Hasna Amalia , Krisdayanti Shendy , Suwandi Luluk Arvi Cahyaning , Irsyada Muhamad Zakky , Faizin Muhammad Nur , Hastuti Novitri , Rengga Wara Dyah Pita
Published: October 2024

Indonesia is the world’s largest palm oil producer and exporter, can produce 230 kg of OPEFB. The utilization of OPEFB is still at 10%, even though OPEFB is composed of 37.26% cellulose. This research aims to find out how to synthesize and characterize cellulose acetate from OPEFB cellulose into membrane material. The synthesis of cellulose acetate using the acetylation method is carried out in several processes. The activation process expands the surface of the cellulose fibers. The acetylation process is intended to substitute cellulose hydroxyl groups with acetyl groups. The hydrolysis removes some acetyl groups from trimester cellulose and reduces the combination of sulfate esters. In the results of FTIR analysis, carbonyl groups (C=O) and acetyl groups (C-O) have high peak depths in OPEFB cellulose acetate. Based on the calculation of acetyl content, OPEFB cellulose acetate has an acetyl content of 39.82% with a degree of substitution of 2.44. The results of XRD analysis show that OPEFB cellulose acetate has a crystallinity index of 34.5%. In TGA analysis, the thermal stability of cellulose acetate is up to a temperature of 210°C. Based on the research results, OPEFB cellulose can be synthesized into cellulose acetate using the acetylation method.
Experimental Investigation of the Mechanical Properties of Woven Abaca (Musa textilis) Fiber-Reinforced Epoxy Composites
Authors: Efriyo Hadi Agung , Cionita Tezara , Parlaungan Siregar Januar , Suffian Mohamed , Zalani Mohamed Reza , Fajar Fitriyana Deni , Rahmat Doni Widodo , Al-Ichlas Imran , Emad Elsherif
Published: October 2024

Abaca fiber which is also known as Musa textilis is a tropical banana species grown primarily for its fiber. It has several advantages when used as a reinforcement in polymer composites caused by its great mechanical performance, increase cellulose content, low cost, and abundant availability. It is important to note that the structure of the fibers used as reinforcing materials is a critical aspect of fabricating a strong polymer composite. Therefore, this study was conducted to determine the effects of layering as well as fiber orientation towards the mechanical characteristics of woven abaca-reinforced epoxy composites. Furthermore, this comprised the application of hand lay-up technique as well as hydraulic press molding in producing 2, 3, and 4 layers of woven abaca-reinforced epoxy composites after which the mechanical properties were analyzed based on its orientation in the warp and weft direction. The results showed that an increase in the number of layers from 2 to 4 did not affect the tensile and flexural properties at every layered stacking sequence of the fiber. Meanwhile, the material in the warp direction indicated a greater tensile as well as flexural properties in comparison to the weft direction. This means the number of layers and orientation of the woven abaca in epoxy composite possesses a significant influence towards the composites’ mechanical properties.
Analyzing Defects in One-Step Double-Acting Friction Stir Welded of Hollow Aluminum Panel: Influence of Travel Speed
Authors: Putri Ericha Dwi Wahyu Syah , Triyono  , Prabowo Aditya Rio , Azka Muizuddin , Muhayat Nurul
Published: October 2024

This study investigates hollow aluminum panels AA6061 produced through extrusion. The One-Step Double-Acting Friction Stir Welding (ODFSW) technique was used to weld the panels. The tool rotated at 1500 RPM, and the travel speeds were 15 and 30 mm/min. ODFSW is a friction stir welding process that uses two tools moving simultaneously on the top and bottom surfaces of the workpiece. This method offers an environmentally friendly alternative to conventional fusion welding, which requires more energy and generates higher greenhouse gas emissions. The research aims to evaluate the influence of travel speed on weld defects in ODFSW joints, including flash, surface surface grooves, and surface roughness. The results show that while higher travel speeds can improve weld quality. It also poses challenges in heat management and material mixing, leading to larger defects on the bottom side due to uneven heat distribution. At a travel speed of 15 mm/min, defects such as long flash, significant surface surface grooves, high surface roughness, and exit holes were observed, mainly due to excessive welding temperatures and extended contact times. In contrast, at 30 mm/min, although surface surface grooves on the top side were reduced, defects on the bottom side increased, along with higher surface roughness.
Kinetics of Separate Hydrolysis and Fermentation of Chlorella in Bioethanol Production
Authors: Megawati  , Astuti W. , Triwibowo B. , A S Bahlawan Z. , A P Bancin W. , R Daksana M. , Indriasari H. , Maulidia M.
Published: October 2024

The objective of this research is to study the hydrolysis kinetics of Chlorella using alpha-amylase and gluco-amylase as well as the fermentation kinetics of its hydrolysate using yeast. Hydrolysis was done on microalgae concentration of 60 g/L, pH of 6, and various temperatures and gluco-amylase volumes. A pretreatment using alpha-amylase was carried out before hydrolysis using gluco-amylase. Fermentation was done using various yeast mass and pH. The kinetics model used was fractal model by Valjamae. Valjamae model could quantitatively describe enzymatics hydrolysis of Chlorella really well. At hydrolysis 50°C, the fractal exponential value is 0.57 and reaction rate constant is 0.63, 0.70, and 0.76 1/h, at gluco-amylase volumes of 1,2, and 3% v/v. Temperature influence follows the Arrhenius law with an activation energy of 10.644 kJ/mol and frequency factor of 25.5 1/hour. During fermentation, the higher the pH, the higher the reaction rate constant, from pH 3 to 6, the values rise from 0.22 to 0.25 1/hour. In addition, because yeast mass increases from 0.25 to 1 g, the values also increase from 0.27 to 1.45 1/hour.
Performance Characteristics of Micro Rubber SIR 20 in Asphalt Mixtures
Authors: Ramdhani Fitra , Subagio Bambang Sugeng , Rahman Harmein , Frazila Russ Bona
Published: October 2024

The development of innovative SIR 20 rubber materials in asphalt mixtures has been carried out by many previous researchers. However, there are still difficulties in the mixing process. Therefore, in this study, SIR 20 rubber was used in micro form to facilitate the mixing process. This research aims to evaluate the impact of incorporating Micro Rubber (MR) SIR 20 as a replacement for asphalt in the AC-WC mixture. The methodology involved testing the morphological characteristics of MR SIR 20 using a Scanning Electron Microscope (SEM) and EDS analysis, followed by assessing the mixture’s properties through the Marshall test. MR SIR 20 was used in proportions of 7%, 9%, and 11%. The Marshall test results indicated that adding MR SIR 20 enhances the Marshall characteristics of the AC-WC asphalt mixture compared to conventional mixtures. Additionally, increasing the MR SIR 20 content in the asphalt reduces the required optimum asphalt content relative to conventional mixtures.
Effervescent Formulation of Oil Palm Leaf Extract as a Free Radical Scavenger
Authors: Azim Mohamad Fahmi Fairul , Nisa Khusnul Khairun , Hayati Sri , Apriliani Nisrina Lutfi , Afandi Achmad Dwi , Astuti Widi
Published: October 2024

Non-communicable diseases have become the leading cause of death in Indonesia, accounting for approximately 69% of deaths in 2023. Various health disorders, such as cancer, neurodegenerative diseases, inflammation, hypertension, and heart disease, are linked to oxidative stress caused by reactive oxygen species (ROS). Chemical treatments often have side effects and high costs, prompting many to turn to natural remedies. One preventive measure against ROS is consuming natural foods rich in antioxidants, such as oil palm leaf extract. This study uses the roller slugging compaction method to transform oil palm leaf extract into effervescent tablets. Palm oil leaf extract has been prepared in 2 different sources ( 1st and 17th leaf) to assess percent inhibition. The experimental results showed that the 17th leaf extract had the highest antioxidant activity value (IC50 = 20.35). Then, the 17th palm oil leaf extract was used in effervescent tablet formulations. The results obtained indicate that formulation 1, consisting of 0.5 grams of oil palm leaf extract, 0.195 grams of citric acid, 0.2925 grams of tartaric acid, 0.4875 grams of NaHCO3, 0.975 grams of maltodextrin, and 0.05 grams of PVP, is the best formula for oil palm leaf extract effervescent tablets. This formulation demonstrated the highest antioxidant activity (IC50 = 30.22), consistent with its total phenolic content (394.451 mg GAE/mL).
Forgotten and Found: Neglected Omphalocele - Vital Role of Imaging
Authors: Mohan Ruchika , Meena Priyanka , Bagri Neha , Gupta Jyoti
Published: October 2024

Background Omphalocele is a congenital abnormality of the abdominal wall consisting of protrusion of the abdominal contents at the base of the umbilical cord. It is associated with genetic and structural defects, which significantly affect its prognosis and survival outcomes.

Case Presentation Prenatal diagnosis of this condition is crucial for apt management; however, we present two cases of neglected and giant omphaloceles in early childhood. It is usually a disease of neonatal age, and presentation at such a late age is quite rare. The management of such cases is quite challenging, and multiple strategies have been described. In our case, the giant omphalocele was managed with an external surgical skin closure system as a component of a staged closure strategy.

Conclusion The expert surgical technique played a decisive role, allowing the coordination of a multidisciplinary team, which was crucial for optimal management.
Psychiatric Etiologies and Approaches in Altered Mental Status Presentations: Insights from Consultation Liaison Psychiatry
Authors: Hamm Brandon , Rosenthal Lisa J.
Published: October 2024

Consultation liaison psychiatrists are frequently asked to evaluate patients with altered mental status (AMS). Psychiatrists have unique perspectives and approaches to care for confused patients, particularly optimizing facilitation of care and maintaining vigilance for diagnostic overshadowing. Psychiatrists also offer expertise in primary psychiatric illnesses that can overlap with AMS, and the most common etiology of AMS is delirium. In this article, we provide a consultation liaison psychiatrist perspective on AMS and related psychiatric conditions in addition to delirium. Manic and psychotic episodes have primary and secondary etiologies, with some symptoms that can overlap with delirium. Catatonia, neuroleptic malignant syndrome, and serotonin syndrome are potentially fatal emergencies, and require prompt index of suspicion to optimize clinical outcomes. Trauma sequelae, functional neurologic disorders, and dissociative disorders can present as puzzling cases that require psychiatric facilitation of care. Additionally, AMS is sometimes due to substance intoxication and withdrawal in the hospital. A nonstigmatizing approach to evaluation and management of delirium and AMS can ensure optimal patient care experiences and outcomes.
Building democratic resilience: the impact of political engagement during education on xenophobia and political trust
Authors: Kiess Johannes
Published: October 2024

This study examines the relationships between political engagement in school or university such as serving as speaker of class or organizing political events and xenophobia and political trust. Following interactionist socialization theory, political engagement during adolescence should shape ideas of citizenship, democracy, and equality and, thus, foster democratic resilience. Schools and universities are arguably key institutions to build trust in political systems and counter-authoritarian dynamics if they provide space for learning democracy by doing. The paper shows that, indeed, political engagement in the context of school or university limits xenophobic views and increases political trust. It further affirms that experiencing efficacy prevents perceiving immigrants as a threat. The original finding that political trust mediates the association between democratic experience and xenophobia further supports this reading. The paper provides evidence from nine European countries (including quotas for young people) for the importance of experiencing democracy through direct engagement at a young age.
Three-dimensional aerodynamic shape optimization with high-order direct discontinuous Galerkin schemes
Authors: Zhang Bin , Wang Kun , Cao Kui , He Xiaofeng , Liu Tiegang
Published: October 2024

In this work, a three-dimensional aerodynamic shape optimization (ASO) framework is established based on the high-order (direct) discontinuous Galerkin (DG/DDG) discretization, which serves as a flow solver for solving compressible Euler/Navier–Stokes equations. The design variables are introduced to represent the shapes via two parameterization approaches, including Hicks–Henne and Free-Form deformation methods. At each loop, the radial basis function mesh deformation technique is employed to redistribute the meshes. Two typical gradient-based optimization methods are employed to update the shapes. One is the Sequential Quadratic Programming method, whose gradients are computed based on the discrete adjoint-based method using finite difference approximation via perturbating the design variables individually. The other is the steepest decent approach, where the gradients are provided by the Simultaneous Perturbation Stochastic Approximation method using finite difference approximation via perturbating the design variables simultaneously and stochastically. These modules work with the DG/DDG flow solver to search for improved shapes in ASO framework. Several airfoil drag minimization experiments involving 2D/3D inviscid/viscous flow are presented to demonstrate the performance of high-order DG/DDG flow solver in ASO, where the drag coefficients can be reduced significantly with the constraints well preserved.
Mitigation of flow-induced vibrations in high-speed flows using triply periodic minimal surface structures
Authors: Piest B. J. T. , Druetta P. D. , Krushynska A. O.
Published: October 2024

Flow-induced vibrations (FIVs) pose challenges and limit intended functionalities in many industrial sectors, especially in high-tech industries such as semiconductor manufacturing. Because of extreme precision requirements, any mechanical perturbation to the manufacturing process detrimentally affects production quality and process yield. The impact of FIV must, thus, be minimized. This study investigates the FIV reducing properties of triply periodic minimal surface (TPMS) inserts in industrial cooling systems by expanding the Darcy–Forchheimer model for flow through porous media to a turbulent regime. Using the expanded model, we performed full-scale finite-element simulations for high-speed flows in a pipe with an abrupt expansion of diameter and analyzed the effects of TPMS inserts on the reduction of induced turbulence and FIV. Our data revealed that the TPMS inserts exhibit promising characteristics for FIV mitigation revealing up to 97.6% reduction in turbulent kinetic energy and 32.7% reduction in vorticity. These results complement available data on using TPMS inserts to eliminate geometry-induced instabilities in internal pipe flows.
The morphology regulation mechanism during coalescence fusion printing of multiple molten droplets
Authors: Zheng Nan , Liu Zhaomiao , Cai Fanming , Zhao Siyu , Zheng Kai , Zhang Chenchen , Pang Yan
Published: October 2024

Molten microdroplet printing technology takes the uniform metal droplet as the basic forming unit, and it is a kind of rapid printing technology based on the shape characteristics of the parts to realize the manufacturing parts. This paper is investigated that during the microdroplet 3D printing (three-dimensional printing), electronics is studied based on the coupled level collective integral number method (coupled level set and volume of fluid) and the equivalent heat capacity method. The influence of the regional wettability characteristics of the heterogeneous functional wettability surface and its matching mode on the droplet spreading and coalescence behavior and the phase transition thermal process is explored. The precise regulation mechanism of heterogeneous functional wettability surfaces on the coalescence and forming of molten droplets is revealed. The results show that the wettability matching schemes of dual-functional-region surfaces and spaced multiple functional region surfaces can effectively regulate the dimensionless feature spreading lengths, dimensionless feature average heights, and dimensionless spreading edge spreading uniformities of the double-droplet and multiple droplet simultaneous impingement and coalescence morphologies, respectively. Under the condition of uniform wettability characteristics of the surface, the heat flow density and average temperature inside the molten fluid at the initial stage of the coalescence of double/multiple droplets show more regular symmetrical characteristics. The heat transfer effectiveness at the gap position is low and decreases with the increase in contact angle; when the surfaces are under heterogeneous bifunctional vs spaced multifunctional wettability conditions, the evolution of the overall heat transfer effectiveness of each type of wettability matching scheme increases with the increase in the wall contact angles of the single type of regions. In addition, when the surface wettability matching scheme includes a transition stage from neutral to superlyophobic, the liquid–gas interface is highly susceptible to overcoming the limitation of the energy barrier and thus instability gradually emerges, resulting in fluctuations of the heat transfer characteristics in its domain. The results of this study further enrich the droplet forming law and its phase transition heat transfer mechanism and provide a general strategy for the high-quality and high-effectiveness preparation of complex flexible electronic devices.
Research on pressure loss calculation and determination of porous media resistance coefficients based on flow simulation of feed counterflow cooler
Authors: Li Jiayi , Si Haiqing , Qiu Jingxuan , Wu Chaochao , Zhuang Di
Published: October 2024

In the feed industry, counterflow coolers are widely used cooling devices. The flow characteristics and pressure loss should be focused on during the design and optimization stages. Due to the complex accumulation of feed particles, it is difficult to accurately analyze the flow field behavior inside the cooler through experiments. Therefore, a detailed study was conducted with a cooler from Buhler using a simulation approach. First of all, the significant influence of the porous jump boundary of flap outlet in the simulation model on the flow field and temperature distribution was revealed. Second, limitations of the Ergun equation in estimating the drag coefficients of the porous medium and the porous jump boundary were explored. Finally, a rapid calculation model for pressure loss was established based on simulation data. Within a wide range of resistance coefficient inputs, the relative error between the model calculation and the corresponding simulation results is very small. Using this model to input a series of resistance coefficients, combined with a small number of overall pressure loss measurements for comparison, the resistance coefficient of the porous medium of the new material can be determined, solving the problem in determining this coefficient through typical measurement experiments at low flow velocity and the lack of effective estimation formulas. This research can provide practical references for improving cooling equipment and enhancing cooler efficiency, and the rapid calculation model can be extended to any fluid machinery containing porous media materials that satisfy Darcy–Forchheimer's law.
Stability of quasi-equilibrium of a binary fluid-inclined layer under the action of high-frequency vibrations
Authors: Lyubimova T. P. , Lyubimov D. V. , Prokopev S. A.
Published: October 2024

The linear stability of quasi-equilibrium states of an inclined binary fluid layer subjected to the gravity field and high-frequency small-amplitude vibrations is studied in the presence of the prescribed vertical temperature and concentration gradients. The rigid boundaries of a layer are impermeable to a substance. The Soret and Dufour effects are neglected. The study is conducted in the average approach. The conditions for quasi-equilibrium state existence are found, and the linear stability of these states to the longwave and finite-wavelength perturbations is investigated. The results of the linear stability analysis are confirmed by the nonlinear modeling, which is carried out by the finite difference method.
Modeling multiphase flow characteristics and particle behavior of mixed charge structure using the particle element method
Authors: Cheng Shenshen , Lu Xinggan , Tao Ruyi , Xue Shao
Published: October 2024

A mixed charge structure is composed of several different types of particles to achieve performance indicators that cannot be achieved by a single particle and usually need to be adjusted and evaluated to determine the parameters in the chamber according to different demand. To balance the accuracy and efficiency, and obtain more calculation parameters, the solid phase is modeled by the particle element method, while the fluid phase is modeled by a computational fluid dynamics solver based on the fifth-order weighted essentially non-oscillatory scheme. In the mixed charge structure of different granular propellant, different particles in different areas are classified and particle elements are divided, and the particle interface position is tracked and captured to form the particle element distribution with different sizes. In the mixed charge structure with central tubular propellant, the granular and the tubular propellants are calculated separately by different types of particle elements, and the source term is used in coupling simulation. Comparing with the calculation results of experiment, the velocity error is less than 1%, and the maximal breech pressure error is less than 3%. In the mixed granular charge structure, due to the differences in combustion rates and movement velocities of the particles, the distribution state of the particles within the chamber is significantly different from that of single particle charge. Additionally, the standard deviation of the porosity is greater in mixed granular charge (0.051: 0.0086). In the mixed charge structure with central tubular propellant, the porosity of tubular and particle distribution in the chamber is discontinuous, and the pressure distribution is effectively predicted. The calculation results show that the perfect consistency of ignition in the chamber, which shows the superior flame-spreading performance of the central tubular propellant. The particle element method can provide a powerful tool for the rapid modeling and simulation of two-phase flow.
A Coulomb collision model based on collision cross section and its effects on kinetic characteristics of atmospheric thermal microplasmas
Authors: Sun Li , Xu Ming , Li Zeng-Yao
Published: October 2024

Coulomb collisions are important transport processes of charged particles and should not be neglected in atmospheric thermal microplasmas due to the high density of charged particles. However, there have been a few attempts at Coulomb collisions in atmospheric thermal microplasmas, and it is still unclear how to couple Coulomb collisions between different charged particles with collisions between charged particles and neutral atoms. This work proposes a Coulomb collision model based on the collision cross section, which is more computationally efficient than the typical Nanbu model and TA (Takizuka and Abebinary) model by reproducing the anisotropic electron–electron collision process. Then, the effects of Coulomb collision on the kinetic parameters and electron dynamics of atmospheric thermal microplasmas are investigated by coupling the implicit particle in cell and Monte Carlo collision (PIC MCC) method. It is found that the existence of electron–electron and electron–ion collisions reduces the particle number density in the bulk-plasma region. The electron–electron collisions are stronger than the electron–ion collisions and the ion–ion collisions can be ignored. The Coulomb collisions increase the dispersion of electron energy in the high-energy region.
Study on the motion characteristics of Janus based on the squirmer model in the flow
Authors: Chen Dongmei , Lin Jianzhong , Xu Jianbao
Published: October 2024

The motion characteristics of Janus in the flow are studied numerically using the lattice Boltzmann method based on the squirmer model. The effects of velocity ratio J on the right and left hemisphere surface of Janus, particle Reynolds number Rep, flow Reynolds number Rec, initial orientation angle φ0 on Janus trajectory, and lateral equilibrium position yeq/H are analyzed. The results showed that, for the motion of Janus in stationary power-law fluids in a channel, Janus moves randomly in a small space in shear-thickening fluids when Rep is low and exhibits three motion modes at Rep = 5. The larger the J value, the easier it is for Janus to reach yeq/H. The higher the Rep, the closer the yeq/H is to the lower wall. In shear-thinning fluids, the motion of Janus exhibits significant randomness at Rep = 0.5 and 1, reaches the same yeq/H at Rep = 2 and 3, and tends toward yeq/H near the centerline and along the upper wall, respectively, at Rep = 4 and 5. For the motion of Janus particles in a channel flow of power-law fluids, in shear-thinning fluids, no matter what value J is, Janus reaches yeq/H on the centerline. The lower the Rep, the closer the yeq/H is to the wall. Two particles move toward yeq/H when Rep ≥ 1. The higher the Rep, the closer the yeq/H is to the centerline. The two particles will exhibit the upstream mode at Rep = 2. Two particles eventually reach yeq/H at different Rec. When φ0 > 0°, the two particles first eventually tend toward yeq/H = 0.2 and 0.8. When the value of φ0 is negative, the larger the absolute value of φ0 and higher the Rep, the more likely particles are to exhibit upstream mode.
Effect of single blade trailing edge side fracture on flow characteristics of centrifugal pump
Authors: Li Huairui , Zhang Rongyong , Chen Huazheng , Liu Yingqian , Tao Fudong , Fu Qiang , Zhu Rongsheng
Published: October 2024

Centrifugal pumps are essential components in various industrial applications, where their stable and efficient operation is critical. The impeller, a key part of these pumps, plays a pivotal role in energy conversion; thus, any fracture in its blades can significantly impact the pump's performance. This study investigates the effects of a single-blade trailing edge fracture on the flow characteristics of a centrifugal pump, aiming to provide insights into fault diagnosis and performance optimization. By employing a combination of experimental analysis and numerical simulation, the study analyzes changes in pump performance, pressure distribution, vortex structures, entropy production, blade loading, transient radial force, and pressure pulsation. The results indicate that minor blade fractures have minimal impact on the pump's head and efficiency, while severe fractures cause a noticeable decrease in head across all flow rates, with efficiency remaining relatively stable at low-flow rates. Transient analyses reveal that blade fractures alter the distribution and magnitude of radial forces, leading to changes in pressure pulsation characteristics, with the shaft passing frequency amplitude increasing and gradually surpassing the blade passing frequency amplitude. These findings provide important references for diagnosing fluid-induced centrifugal pump failures, effectively enabling the extraction of hydraulic features to optimize the fault diagnosis process.
On the mechanics of conducting micropolar fluids with magnetic particles: Vorticity–microrotation difference
Authors: Aslani Kyriaki-Evangelia , Tzirtzilakis Efstratios , Sarris Ioannis E.
Published: October 2024

In this paper, mechanisms that differentiate microrotation (i.e., particles' internal rotation) and vorticity in magnetohydrodynamic micropolar flows with magnetic particles are examined. Micropolar fluids are characterized by the asynchronization of the microrotation and the vorticity of the liquid carrier. When the microrotation is equal to the fluid's vorticity, the flow is purely Newtonian. In this context, two classical examples of micropolar magnetohydrodynamic fluids with magnetic particles are used, namely, blood and ferrofluid. The effect of all dimensionless parameters associated with the mathematical model is examined in terms of differentiating microrotation and vorticity. These dimensionless parameters are specifically calculated using the physical properties of the ferrofluid and blood. It was shown that higher values of the rotational viscosity (which are associated with smaller values of the spin relaxation time), higher values of channel's height, and higher values of the microrotation wall parameter tend to equalize microrotation and vorticity. On the other hand, the spin viscosity and the micromagnetorotation (magnetic torque) are mechanisms that differentiate microrotation and vorticity. Lorentz force does not seem to have any noticeable effect on the microrotation–vorticity difference. It is anticipated that this study will reveal the cases where a magnetohydrodynamic micropolar fluid with magnetic particles, such as blood and ferrofluid, can be simplified to a Newtonian one, which brings many benefits associated with a simplified mathematical flow model (such as smaller computational cost and less time).
Drag coefficient of bent-awn plumegrass (Saccharum contortum) seeds in wind
Authors: Faraji Dizaji Farzad , Wang Binbin , Sullivan Lauren L. , Kellogg Elizabeth A.
Published: October 2024

We present a combination of laboratory experiments and computational fluid dynamics (CFD) simulations to understand the wind-induced drag force and drag coefficient for Saccharum contortum seeds. Seed drop experiments indicate that the settling fall velocities of hair-equipped seeds are within 1–2 m/s, compared to 2.34 times higher settling fall velocity of the seed without hairs. The experimental data illustrate a power-law relationship between drag coefficient (Cd) and Reynolds number (Re) under the free fall condition: Cd∼Re−1.1. CFD simulations show that both viscous and pressure drag force components are important in contributing to wind drag. The presence of hairs substantially increases pressure drag, and its relative importance depends on hair number and orientation. Seed morphology including hair number and orientation influences the drag coefficient under different flow directions relatively to the seed body. The lower drag coefficient observed with crossflow wind compared to free fall suggests that seeds encounter less air resistance while drifting horizontally in the wind, favoring extended flying time and distance. Based on the varying drag coefficients under different conditions, we propose the incorporation of varying drag coefficients in future wind-driven seed dispersal models.
Entropy production minimization in channel flows using computational fluid dynamics and physics-informed neural networks
Authors: Jiang Huadong , Yu Jianyang , Lan Sichao , Chen Fu
Published: October 2024

This study is based on two objective functions: minimizing heat transfer entropy production and minimizing viscous dissipation. The reverse-temperature equation and volumetric force sources are derived using variational methods for optimizing convective heat transfer in two-dimensional flows. Linear weights are adjusted to generate velocity and temperature fields corresponding to different performance metrics. The research demonstrates that the flow patterns determined through optimization effectively characterize optimal heat transfer performance under varying flow power consumption. Furthermore, compared to non-optimized flows, linear weights induce transitions in velocity and temperature fields from mild to highly perturbed states. Additionally, addressing the reverse-temperature equation with a negative diffusion coefficient that is challenging for traditional numerical methods, we utilize a physics-informed neural network strategy for solution. This approach significantly reduces the required grid resolution. The findings of this study can be applied to design passive techniques enhancing wall-to-fluid heat transfer and provide a novel approach for solving systems of mixed conventional and non-classical partial differential equations.