Grid Method Research Articles

Boundary layer flow and heat transfer enhancement by utilizing Casson ternary nanofluid past a horizontal cylinder in a non-Darcy porous medium with thermal radiation effects – Non-similar solutions

The aim of this study is to examine the results of MHD, radiation and Casson ternary fluid over a horizontal cylinder with a saturated porous medium. The nanofluids used in this study are trihybrid, consisting of Cu, Al2O3 and Tio2 particles suspended in blood as the base fluid. The dimensional form of governing equations is transformed into dimensionless form by manipulating non-similar solutions. The conservation equations are solved using the Keller Box Method (KBM). The presence of several emerging dimensionless parameters, namely the Casson fluid parameter (β), Darcy number (Da), Forchheimer parameter (∧), radiation parameter (Rd) and magnetic field (M) on fluid momentum and energy changes in the boundary layer regime are investigated in detail. The Prandtl value (Pr) for blood is determined to be 21. The application of porous medium models spans across various fields, including engineering, environmental science, biology, and materials science.

Two-phase numerical simulation of thermal and solutal transport exploration of a non-Newtonian nanomaterial flow past a stretching surface with chemical reaction

Abstract Non-uniform heat sources and sinks are used to control the temperature of the reaction and ensure that it proceeds at the desired rate. It is worldwide in nature and may be found in all engineering applications such as nuclear reactors, electronic devices, chemical reactors, etc. In food processing, heat is used to cook such as microwave ovens, pasteurize infrared heaters, and sterilize food products. Non-uniform heat sources are mainly used in biomedical applications, such as hyperthermia cancer treatment, to target and kill cancer cells. Because of its ubiquitous nature, the idea is taken as our subject of study. Heat and species transfer analysis of a non-Newtonian fluid flow model under magnetic effects past an extensible moving sheet is modelled and examined. Homogeneous chemical reaction inside the fluid medium is also investigated. This natural phenomenon is framed as a set of Prandtl boundary layer equations under the assumed convective surface boundary constraint. Self-similarity transformation is employed to convert framed boundary layer equations to ordinary differential equations. The resultant system is solved using the efficient finite difference utilized Keller box method with the help of MATLAB programming. The influence of various fluid-affecting parameters on fluid momentum, energy, species diffusion and wall drag, heat, and mass transfer coefficients is studied. Accelerating the Weissenberg number decelerates the fluid velocity. The temperature of the fluid rises due to variations in the non-uniform heat source and sink parameters. Ohmic dissipation affects the temperature profile significantly. Species diffusion reduces when thermophoresis parameter and non-uniform heat source and sink parameters vary. The Eckert number enhances the heat and diffusion transfer rate. Increasing the chemical reaction parameter decreases the shear wall stress and energy transmission rate while improving the diffusion rate. The wall drag coefficient and Sherwood number decrease as the thermophoretic parameter increases whereas the Nusselt number increases. We hope that this work will act as a reference for future scholars who will have to deal with urgent problems related to industrial and technical enclosures.

Geophysical delineation of the newly identified Gulmarg fault in the Kashmir Basin, NW Himalaya. Implications for active structural control

The Kashmir Basin, shaped by the collision of the Indian and Eurasian tectonic plates, features prominent faults, including the Balapur fault and other fault zones. This study focuses on the Gulmarg fault within the Northwestern Himalaya, using advanced geomagnetic techniques for delineation. Geomagnetic measurements reveal the characteristics of the newly identified Gulmarg fault. Ground magnetic surveys with Proton Precession Magnetometers along linear profiles and a magnetic grid highlight fault-related anomalies. The results indicate a fault running through the Gulmarg meadows, approximately 1.6 ​km from the Balapur fault, suggesting a potential coupling between the two. Three profiles across the fault exhibit distinctive magnetic variations, highlighting the intricate nature of the fault structure. Gridding methods also reveal anomalies associated with subsurface water and hydraulic activities, underscoring the importance of advanced geophysical techniques. This study emphasizes the significance of detailed investigations to unravel the complex geological processes shaping the Kashmir Basin. The study provides valuable insights into the tectonic activity in the Gulmarg region, underscoring the role of geophysical studies in enhancing our understanding of dynamic geological structures like the Gulmarg fault zone.

Safety and energy saving dispatching method of large power grid considering demand response

Safety and energy saving dispatching method of large power grid considering demand response

Rapid assembly bolt connection design method for TBM disc cutter box based on AHP

With the TBM disc cutter box as the subject of investigation, this study addresses the intricate and labor-intensive nature of the assembly process in TBM disc cutter box welding assembly. In order to expedite the assembly of the cutter-head and disc cutter box, an alternative approach utilizing combined bolt connections is implemented in place of welding assembly. Therefore, this article proposes a TBM disc cutter combination bolt connection design method based on AHP. Initially, a hierarchical analysis model is constructed, taking into account the actual conditions of the TBM disc cutter box combined bolt connections. Subsequently, from the array of factors influencing bolted connection performance, five experimental variables were chosen, and an orthogonal experimental layout was devised to examine the stress dispersion in the TBM disc cutter box under conditions of bolted assembly, employing finite element analysis. By conducting extreme difference analysis, the study examined the effects of each experimental factor on the bolt connection performance, and determined the order of importance of each factor more objectively. Thus, the comprehensive weights of each factor were calculated, and the optimal solution of the bolt connection scheme was selected by synthesizing the effects of multiple factors.

Parallel Modeling of Elastic Wave Propagation, with Explicit Pore Delineation Using Overset Grids Method

Parallel Modeling of Elastic Wave Propagation, with Explicit Pore Delineation Using Overset Grids Method

Perancangan Sistem Informasi Pengumuman dan Komunikasi Berbasis Web di SMK Skyhigh

The effective and efficient use of information systems is a major challenge for Skyhigh Vocational High School (SMK Skyhigh) in delivering timely and structured information to students and parents. This study aims to design and develop a web-based announcement and communication information system that can improve the accessibility and speed of information distribution within the school environment. The research employs the waterfall software development method, which includes the stages of planning, design, development, and testing. The results show that the system, built using PHP, JavaScript, HTML, and CSS, successfully meets client needs by providing an intuitive and responsive interface. Testing with both black box and white box methods indicates that all system components function well and comply with the specified requirements. In conclusion, this system offers a relevant and practical solution to communication needs at SMK Skyhigh and has the potential to be adapted by other educational institutions.

Perancangan Sistem Informasi Pengumuman dan Broadcasting (NotifyCasting)

Managing announcements and communication within a company often faces challenges in ensuring the effective and timely dissemination of information. This study aims to design and develop a web-based Announcement and Broadcasting Information System (NotifyCasting) to improve efficiency in information distribution within the company environment. The method used is the waterfall software development model, which includes the stages of requirement analysis, design, implementation, testing, and system maintenance. The results of the study show that the system successfully meets the functional and non-functional needs of the company by providing features such as real-time messaging and announcement delivery, audience filtering, and an accessible announcement archive. Testing with black box and white box methods indicates that the system functions according to the specified requirements, and the user interface is intuitive and easy to use. In conclusion, the NotifyCasting system can significantly enhance communication effectiveness within the company and can be adapted by other organizations for similar purposes.

User Acceptance Test Aplikasi Mobile SI CANTIK BANGSA untuk Pencatatan Kesetaraan Gender dalam Pembangunan Desa

Gender equality is a complex issue that is difficult to eliminate in a society with a strong patriarchal culture. The Gender Empowerment Index (IDG) of Kebumen Regency decreased from 66.89% in 2021 to 66.86. The Kebumen Regency Government together with Institut Teknologi Telkom Purwokerto adopted the Si Cantik Bangsa Platform to support the activities of WANI LEmPER program cadres. This study aims to test the SI CANTIK BANGSA Mobile Application for recording gender equality in village development using the User Acceptance Test (UAT) method, namely alpha testing and beta testing. The results of alpha testing with the black box method show that all application modules are functioning properly. Beta testing using the System Usability Scale (SUS) resulted in an average score of 78.25, which means the application is acceptable with a grade C and an adjective rating of "Good". In conclusion, the Si Cantik Bangsa Mobile Application can be accepted by users, but it needs system improvement. The analysis showed the 6th question had the lowest score of 2.9 and the 9th question a score of 3.1, indicating areas in need of improvement

Ground state properties of the screened helium atom under harmonic confinement

In this contribution, we show electronic property results for the ground state of the helium atom screened by a Debye plasma under an isotropic harmonic confinement as a function of the screening length (λD) and the angular frequency (ω0). The associate Hamiltonian is solved by expanding the wave function in the Hylleraas basis to incorporate the electron correlation in a simple manner. Furthermore, in order to compare with other findings the Hartree–Fock approach is implemented using a numerical grid method. The main results show that the total energy reaches the ionization threshold by the action of the electron coupling with the plasma medium and the strength of the harmonic confinement. The electron–electron average distance shows the compression of the system as the Debye plasma and the harmonic interactions become strongest (low λD and large ω0 values). We found acceptable results for the electron correlation energy when separate interactions are considered. In the absence of both interactions, the findings are in excellent agreement with other theoretical results.

Elastic reverse time migration based on nested triangular mesh in 2D isotropic media

Abstract Reverse time migration (RTM) based on two-way wave equation is an important imaging tool, which has been widely used in exploration geophysics. It offers distinct advantages in handling complex geological structures. Moreover, elastic reverse time migration (ERTM) can produce more physically meaningful images for subsurface and has received increasing attention in recent years. However, rugged topography presents challenges in the reconstruction of subsurface structures for ERTM. To overcome this problem, we introduce the grid method for topography ERTM, which is an unstructured mesh based algorithm. However, the conventional gird method for RTM is implementing by discretizing model into small meshes, leading to high computational cost. To address this problem, we introduce the grid method based on nested unstructured meshes to implement ERTM with complex surface topography. Low-order small meshes, due to their fine scale, can accurately depict complex surface topography. However, their generation process is relatively time-consuming. In contrast, high-order large meshes contain many similar small meshes internally, which can be processed in parallel, resulting in higher computational efficiency. Therefore, we propose the following strategy: for the receiver wavefield, several layers on surface discreted by the small meshes are used to place receivers and remaining layers discreted by the large meshes to improve computational efficiency. For the source wavefield, only the large meshes are used because the spacing of shot is relatively large. In this way, we ensure the accurate description of complex surface topography for the implementation of ERTM with high computational efficiency. Finally, the effectiveness of our method is validated through experiments on three models with complex topography.

Raining-inspired method for construction of porous film material

The low-temperature environment caused by solvent evaporation leads to the condensation of water vapor into water droplets that remain on the surface of the film to form breath figure patterns. The conventional approach to regulate the pore morphology in the breath figure process is to optimize the ambient temperature, humidity, and solution concentration. However, realizing a wide adjustable window of pore size and uniform distribution of the pore are still challenges. Here, inspired by the rainfall phenomenon, we proposed a simple and efficient method called the “raining boxing method” (RBM) for preparing porous films based on exogenously given water droplets as templates. The RBM broadened the adjustable window of pore size (0.6–225 µm in this work) and solved the inherent problem of radial reduction of pore size from the film center to the edge caused by the significant difference in low-temperature duration at different locations accompanying the solvent evaporation process. Furthermore, this method could realize multi-types porous films, including surface porous films, spongy porous films, and honeycomb porous films, and could be universally applied in the casting process of various polymer solutions.

Properties of different graded coir pith by Keen-Raczkowski box and Brunauer-Emmett-Teller analysis

Aim: To evaluate the physical and hydrological properties of different graded coir pith and composted coir pith (CPOM) following the Keen-Raczkowski box and Brunauer-Emmett-Teller (BET) analysis. Methodology: The coir pith was collected and composted by PITH PLUS (Pleurotus-sajor-caju). Thereafter, the coir pith and composted coir pith were segregated into different groups based on the size of the particles as 1.0 mm (1000 microns), 0.5 mm (500 microns), and 0.25 mm (250 microns). Based on particle size, the hydrological properties of coir pith and composted coir pith were determined. The physical and hydrological properties were estimated by the Keen-Raczkowski box method and Brunauer-Emmett-Teller analysis. Results: Different graded coir pith and composted coir pith of size 0.25 mm showed the highest bulk density (0.60 and 0.48 g cm-3), followed by 0.5 mm size coir pith and composted coir pith, respectively. The highest particle density (0.18 and 0.19 g cm-3) was registered in 1.0 mm coir pith and composted coir pith whereas the lowest particle density was observed in 0.25 mm size coir pith (0.15 g cm-3). The water-holding capacity (817.93 % and 806.97 %) and water in air-dry substrate (25.03 % and 36.094 %) was high in 0.25 mm coir pith and composted coir pith. Interpretation: A 0.25 mm grade of coir pith and composted coir pith showed highest water holding and retaining capacity due to a greater number of small particles being compactly arranged and holding more surface area, and innumerable micropores than other graded particles. Key words: BET analysis, Coir pith, Composted coir pith, Water holding capacity

A new very high-order finite-difference method for linear stability analysis and bi-orthogonal decomposition of hypersonic boundary layer flow

Precisely predicting laminar-turbulence transition locations is essential for improvements in hypersonic vehicle design related to flow control and heat protection. Currently state-of-the-art eN prediction method requires the evaluation of discrete normal modes F and S for the growth rate of instability wave. Meanwhile, in receptivity studies, both the discrete and continuous modes, including acoustic, entropy, and vorticity modes, contribute to the generation of the initial disturbance. The purpose of this paper is to introduce a new very high-order numerical method to accurately compute these normal modes with finite-difference on a non-uniform grid. Currently, numerical methods to obtain these normal modes include two major approaches, the boundary value problem approach and the initial value problem approach. The boundary value approach used by Malik (1990) [17] deploys fourth-order finite difference and spectral collocation methods to solve a boundary value problem for linear stability theory (LST). Nonetheless, Malik's presentation only demonstrated the computation of discrete modes, but not the continuous modes essential for conducting modal analysis on receptivity data. To obtain the continuous spectrum for his multimode decomposition framework, Tumin (2007) [16] relies on an initial value approach based on the Runge Kutta scheme with the Gram-Schmidt orthonormalization. However, the initial value approach is a local method that does not give a global evaluation of the eigenvalue spectra of discrete modes. Furthermore, Gram-Schmidt orthonormalization, which can be error-prone in implementation, is required at every step of the integration to minimize the accumulation of numerical errors. To overcome the drawbacks of these two approaches, this paper improves the boundary value approach by introducing a new general very high-order finite difference method for both discrete and continuous modes eigenfunctions. This general high-order finite difference method is based on a non-uniform grid method proposed by Zhong and Tatineni (2003) [22]. Under the finite difference framework, discrete and continuous modes can be obtained by imposing proper freestream asymptotic boundary conditions based on the freestream fundamental solution behavior. This asymptotic boundary condition is used for obtaining both discrete and continuous modes that have both distinct (acoustic) and similar (vorticity and entropy) eigenvalues. Extensive verification of the new method has been carried out by comparing the computed discrete and continuous modes. Subsequently, the discrete and continuous modes obtained with this finite difference method are essential for the bi-orthogonal decomposition, which holds promising potential in obtaining an accurate evaluation of receptivity coefficients. The result of the bi-orthogonal decomposition for a hypersonic boundary layer flow over a flat plate is verified by comparing with existing results. Ultimately, the bi-orthogonal decomposition using the eigenfunctions has been applied to a case of freestream receptivity simulation for an axis-symmetric hypersonic flow over a blunt nose cone with modal contributions computed as coefficients for receptivity analysis.

Nonanatomical femoral tunnel positioning in isolated MPFL reconstruction is not associated with an increased risk of patellofemoral osteoarthritis after a minimum follow-up of 10 years.

The association between the prevalence of patellofemoral arthritis (PFA) and femoral tunnel positioning following isolated medial patellofemoral ligament reconstruction (MPFLr) has not been well described. The aim of this study was to analyse the relationship between femoral tunnel positioning and the prevalence of PFA. This was a single-centre study of patients undergoing an isolated MPFLr between 2006 and 2011 with a minimum of 10 years of follow-up. Outcomes assessed were the presence of PFA on radiographs, recurrence of instability requiring revision surgery and patient-reported outcomes, including Kujala, Tegner and IKDC scores. Tunnel positioning was assessed on postoperative radiographs using two radiographic methods: Schöttle's point and the grid method to localise the femoral tunnel. Patients were grouped based on tunnel positioning and compared. Fifty patients were analysed at a mean follow-up of 12.4 years. Thirty-three patients (66%) had a femoral tunnel position within 7 mm of Schöttle's point and 39 (78%) within the anatomic quadrant, with the most common location according to the grid method in D4 (28%) and E4 (26%), respectively. Thirty-seven patients (74%) had a satisfactory (>80 versus <80) Kujala score at long-term follow-up. None of the examined tunnel assessment methods demonstrated a significant relationship with Tegner, Kujala or International Knee Documentation Committee scores. Patients with a femoral tunnel position >7 mm outside Schöttle's pointor were considered to be in a nonanatomic position were not significantly more likely to result in unsatisfactory Kujala scores at the last follow-up. Tunnel positioning and the other tested parameters were not found to be significantly associated with the development of PFA. No correlation between femoral tunnel position and risk of PFA or poor outcomes was observed in patients undergoing isolated MPFLr at long-term follow-up. The impact of femoral tunnel placement on long-term outcomes in patients with PFI may be less significant than originally considered. Level IV.

Variable viscosity effects on dynamic of non-Newtonian fluid nanofluid over a paraboloid of revolution via Keller box method

Variable viscosity effects on dynamic of non-Newtonian fluid nanofluid over a paraboloid of revolution via Keller box method

Implementasi Metode Prototype pada Pembuatan Web Portal TEFA House of Health Promotion

Health Promotion is a series of activities that strive for individuals to increase their knowledge related to health so that ultimately they can improve the quality of health. In order for the objectives of health promotion activities to be achieved, media is needed to support these activities. TeFa House of Health Promotion Polije is one of the TeFa (Teaching Factories) managed by the Health Promotion study program, Department of Health. TeFa was created as a forum for communication, information and health education, TeFa is also a means for lecturers to contribute to society by providing consultation services related to the development of public health promotion programs. To support this, a multifunctional platform is needed in the form of a webportal which is used to help TeFa. This research focuses on creating a web portal using one of the SDLC methods, namely prototype. The process of creating a web portal begins with extracting information through interviews with potential users. The results of this excavation process are information related to the features of the web portal, including articles, video, audio, pooling and chat. The process of creating a Web Portal is made using the PHP programming language and Laravel Framework. The testing process is carried out using the black box method to determine the functionality of each feature. The test results showed that the web portal was in accordance with the user's required features and each feature was functioning according to its function.

On the convergence of the Rhie–Chow stabilized Box method for the Stokes problem

AbstractThe finite volume method (FVM) is widely adopted in many different applications because of its built‐in conservation properties, its ability to deal with arbitrary mesh and its computational efficiency. In this work, we consider the Rhie–Chow stabilized Box method (RCBM) for the approximation of the Stokes problem. The Box method (BM) is a piecewise linear Petrov–Galerkin formulation on the Voronoi dual mesh of a Delaunay triangulation, whereas the Rhie–Chow (RC) stabilization is a well known stabilization technique for FVM. The first part of the article provides a variational formulation of the RC stabilization and discusses the validity of crucial properties relevant for the well‐posedness and convergence of RCBM. Moreover, a numerical exploration of the convergence properties of the method on 2D and 3D test cases is presented. The last part of the article considers the theoretically justification of the well‐posedness of RCBM and the experimentally observed convergence rates. This latter justification hinges upon suitable assumptions, whose validity is numerically explored.

Comparison of the effectiveness and efficiency of the grid and link search methods to recover scattered skeletal remains

The grid and link search methods are used to recover scattered skeletal remains. Neither have not been compared robustly and clear guidelines for the link method have not been sufficiently developed. The study aimed to compare the effectiveness and efficiency of both methods and propose guidelines for the link method. The scattering patterns of two scavengers of forensic relevance—slender mongooses (Galerella sanguinea) and black-backed jackals (Canis mesomelas)—were recreated using four pig skeletons (Sus scrofa domesticus). Two groups (n = 6 each) were assigned a different method to recover the scattered remains. The length of the search and when each bone was located for each scatter pattern was recorded for each group and scatter pattern. A Likert scale questionnaire assessed participants’ perceptions of their assigned method. A paired t-test (p = 0.005) compared the efficiency of each method and the questionnaire answers. Both methods were effective, recovering 100% of all remains. The link method was more efficient for both scatter patterns, despite there being no statistical significance (jackal: p = 0.089; mongoose: p = 0.464). Participants indicated favorable views for both methods; however, the link method scored significantly more favorably (p = 0.01) for efficiency. Specific guidelines were developed for the use of the link method. The link method is suggested for the recovery of scattered remains in forensic contexts, especially when the scavenger, its behavior, and scattering pattern is known or suspected.

Analysis of landscape pattern vulnerability in Dasi river basin at the optimal scale

Since the reform and opening up in 1978, the Dasi River Basin within Jinan’s startup area from replacing old growth drivers with new ones (startup area) has experienced rapid urbanization and industrialization, and the landscape pattern has changed significantly, resulting in a series of eco-environmental problems. In order to more accurately identify the vulnerable areas of landscape pattern, understand their cause mechanism and changing laws, and provide a theoretical basis for the implementation of sustainable landscape pattern planning and management in the region. Four Landsat images of 2002, 2009, 2015 and 2020 were taken as data sources, and the optimal granularity of landscape pattern analysis was determined from the perspective of landscape level and class level by using the coefficient of variation method, granularity effect curve and information loss model, and the optimal amplitude was determined by using the grid method and semi-variance function. Then, the landscape vulnerability assessment model was constructed based on the optimal scale, and its spatiotemporal evolution characteristics and spatial autocorrelation were analyzed. The result showed that: (1) The optimal granularity of landscape pattern analysis in this study area was 80 m, and the optimal amplitude was 350 × 350 m. (2) During 2002–2020, the overall vulnerability of landscape pattern in the southern part of the study area showed an increasing trend, while that in the middle and northern parts showed a decreasing trend. (3) The mean values of the vulnerability index of the overall landscape pattern in 2002, 2009, 2015 and 2020 were 0.1479, 0.1483, 0.1562 and 0.1625, respectively, showing an increasing trend year by year. In terms of land use, during 2002–2020, the average vulnerability indices of forestland and built up land increased by 23.18% and 21.43%, respectively, followed by water body and bare land, increased by 12.18% and 9.52%, respectively, while the changes of cropland and grassland were relatively small, increasing by 5.36% and 5.65%, respectively. (4) During 2002–2020, the landscape pattern vulnerability showed a significant spatial positive correlation in terms of spatial distribution. The Low-Low areas were generally transferred from the southeastern and midwestern to the middle and northern, and the High–High areas were mainly transferred from the middle to the southern. Overall, the degree of the spatial agglomeration of the landscape pattern vulnerability showed an increasing trend.