Static Fluid Research Articles

Static perfect fluid space-time and paracontact metric geometry

The main purpose of this paper is to study and explore some characteristics of static perfect fluid space-time on paracontact metric manifolds. First, we show that if a [Formula: see text]-paracontact manifold [Formula: see text] is the spatial factor of a static perfect fluid space-time, then [Formula: see text] is of constant scalar curvature [Formula: see text] and squared norm of the Ricci operator is given by [Formula: see text]. Next, we prove that if a [Formula: see text]-paracontact metric manifold [Formula: see text] with [Formula: see text] is a spatial factor of static perfect space-time, then for [Formula: see text], [Formula: see text] is flat, and for [Formula: see text], [Formula: see text] is locally isometric to the product of a flat [Formula: see text]-dimensional manifold and an [Formula: see text]-dimensional manifold of constant negative curvature [Formula: see text]. Further, we prove that if a paracontact metric 3-manifold [Formula: see text] with [Formula: see text] is a spatial factor of static perfect space-time, then [Formula: see text] is an Einstein manifold. Finally, a suitable example has been constructed to show the existence of static perfect fluid space-time on paracontact metric manifold.

On the study of complexity for charged self-gravitating systems

In modified Gauss–Bonnet gravity, this paper investigates the complexity factor for static anisotropic self-gravitating fluid which is influenced by an electric charge. For the self-gravitating system, we evaluate the Maxwell field equations, the Tolman–Oppenheimer–Volkoff equation and the mass function. We formulate the structure scalars by an orthogonal splitting of the Riemann tensor for the self-gravitating system and identify one of these scalars as the complexity factor. Then with the help of two different models, we observe the corresponding complexity factor involved in the subsequent changes of static spheres. The structure scalars and complexity factor are found to be dependent on the components of the effective part as well as electromagnetic part.

Hyperbolically symmetric sources in [formula omitted] gravity

This paper studies the static fluid distributions admitting the hyperbolically symmetric structure by extending the work of Herrera et al. (2021) in f(R,T) gravity. The unavailability of the fluid distribution in the region which is close to the center of symmetry has been observed. A vacuum cavity can be used to depict this region around the center. The effective matter density emerges inevitably to be negative and this implies that the conceivable use of such fluids needs transcendental physical conditions when the significant quantum effects are observed. Furthermore, the Tolman mass, as well as an appropriate formulation of the mass function, are particularly computed. Along with this, we evaluated the structure scalars through the orthogonal splitting of the Riemann tensor in this modified gravity. Imposing the conditions of conformal flatness and stiff equation of state, we constructed several models for the less-complex systems. We also evaluated the generating functions to study the fluid distribution in this theory. A general hypothesis to attain precise solutions are also conferred through matter-curvature coupling.

Analysis of Students' Creative Problem-Solving Ability in Static Fluids: Pilot study

This study aims to describe the ability of creative problem solving in static fluid materials. The method used in this study is a descriptive method which was carried out at SMAN 4 Luwu, North Sulawesi. The research sample was 36 students. The research data were collected through the provision of creative problem solving tests on static fluid materials given after the learning process was carried out. The data that has been collected is then analyzed using the calculation of the average pretest and posttest and Rasch Analysis. The results of data analysis show that reviewing four indicators, namely fact finding, problem finding, idea finding, solution finding and the highest score is on the fact finding indicator with an average of 67.57 for classes that use creative problem solving. In implementing the creative problem solving learning model, it is necessary to pay attention to the time management allocated so that each implementation can be carried out properly. The creative problem solving learning model can be tested on other materials according to school conditions. Keywords: reative problem solving, static fluids, Rasch analysis. Abstrak: Penelitian ini bertujuan mendeskripsikan kemampuan creative problem solving pada materi fluida statis. Metode yang digunakan dalam penelitian ini adalah metode deskriptif yang dilakukan di SMAN 4 Luwu Sulawesi Utara. Sampel penelitian sebanyak 36 siswa. Data-data penelitian dikumpulkan melalui pemberian tes creative problem solving pada materi fluida statis yang diberikan setelah proses pembelajaran dilakukan. Data yang sudah dikumpulkan selanjutnya dianalisis menggunakan perhitungan rata-rata pretest dan posttest serta Rasch Analysis. Hasil analisis data menunjukkan bahwa meninjau empat indikator yaitu fact finding, problem finding, idea finding, solution finding dan skor yang paling tinggi adalah pada indikator fact finding dengan rata-rata 67,57 untuk kelas yang mengguanakan creative problem solving. Dalam menerapkan model pembelajaran creative problem solving perlu memperhatikan manajemen waktu yang dialokasikan agar setiap pelaksanaan dapat dilaksanakan dengan baik. Model pembelajaran creative problem solving dapat diujicobakan pada materi lain sesuai dengan kondisi sekolah. Kata kunci: pemecahan masalah secara kreatif, fluida statis, analisis Rasch. DOI: http://dx.doi.org/10.23960/jpmipa/v23i3.pp816-823

Estimation of almost Ricci-Yamabe solitons on static spacetimes

This research work examines the standard static spacetime (SSST) in terms of almost Ricci-Yamabe soliton with conformal vector field. It is shown that almost Ricci-Yamabe soliton in standard static spacetime with function ? satisfies Poisson-Laplace equation. Next, we consider the function ? is harmonic and discuss the harmonic aspect of almost Ricci-Yamabe soliton on SSST. In addition, we investigate the nature of almost Ricci-Yamabe soliton on SSST with non-rotating Killing vector field. Also, we exhibit that non-steady non shrinking almost Ricci-Yamabe soliton i.e., ?? 0 on smooth, connected, and non-compact SSST with Killing vector field satisfies the Schr?dinger equation for a smooth function ?. Finally, we study almost Ricci-Yamabe soliton on static perfect fluid and vacuum static spacetime with conformal Killing vector field.

Development of All Metal Multi-plate-type Capacitive Void Fraction Sensor for gas-liquid two-phase flow

In the aerospace field, liquid hydrogen and oxygen which are “cryogenic fluid” are used as the propellant for rockets and hypersonic engines. These fluids become easily a gas-liquid two-phase flow in pipes and fluid machines. We have developed small capacitive void fraction sensors which can measure in real time, which is used to control the flow rate of cryogenic fuel and to understand typical two-phase flow phenomena such as the cavitation. The conventional capacitive sensors have a structure in which two electrodes sandwich a pipe made of dielectric material. However, the dielectric material has problems such as insufficient strength under high pressure condition and decreasing measurement accuracy due to changes in dielectric constant with temperature change. We developed a new capacitive sensor which consists of only metal parts to solve these problems. On the other hand, it may cause a decrease in measurement accuracy due to the structural limitation. This paper presents the results of the electric field analysis and the static fluid experiment using silicon oil and air to verify the accuracy of the sensor. The mean errors obtained by the analysis and the experiment are 3.47 % and 5.32 %, respectively, which almost satisfy the required specification. However, it was found that the accuracy is poor in some void fraction ranges, and the sensor needs to be improved.

Wind-structure interaction analysis of empty cylindrical silos for various slenderness ratio

Wind is the flow of air within the earth’s atmosphere, which affects any structure greatly. Studies on the effect of wind loading on shell structures is an important field of structural research. Many shell structures, such as, chimneys, silos, tanks etc. are an integral part of the advancement of the industry and agriculture. Such shell structures are vulnerable against aerodynamic excitation and can be subjected to structural failure due to vortex-induced vibration, ovalling, buckling, rupture, over-turning etc. The present study focuses on the static fluid–structure interaction analysis to assess the wind pressure and wind-induced deformation of cylindrical silo shells. Cylindrical silos are a type of shell structure for storing granular materials, such as grains, wheat, cement, coal, fly-ash etc. Cylindrical silos very much susceptible to radial deformation and buckling failure under wind loading in empty state. In the present study the authors have conducted the wind-structure interaction studies on intermediate to tall (slenderness ratio range: 1.5 to 4.0) cylindrical silo shells for terrain category 2, as per IS-875: part 3, 2015. The silos are flat topped with uniform thickness and fixed at the base, free at the top. The logarithmic law is used to simulate wind velocity profile. The circumferential mean wind pressure coefficient distribution for each silo, is calculated and compared with Indian standard. This study is conducted for smooth flow with very low turbulence intensity for simplicity. This study exhibits that, with the increase in slenderness ratio from 1.5 to 4.0, the magnitude of negative pressure coefficients decreases, however no significant increase can be seen for positive pressure coefficients. The sway of the silos increases with the increment in slenderness ratio. The radial deformation is dominant in the intermediate portion and the nature of deformation is typical for each silo. Based on the nature of radial deformation the critical locations can be identified, which need to be strengthened to resist wind-induced deformation. It is also seen that the presence of flat roof provides significant strengthening at the top of the silos against wind-induced radial deformation.

PENGARUH MODEL PEMBELARAN BEBASIS PROYEK TEHADAP KEMAMPUAN PEMECAHAN MASALAH SISWA PADA MATERI FLUIDA STATIS

This study aims to determine the effect of the PjBL learning model on students' problem-solving abilities on the material of Static Fluids at MA Sabilurrasyad in Class XI MIA 1 and XI MIA II. The type of research used is a quasi-experimental which aims to determine the problem solving ability of students who learn to use PjBL and conventional models. Data analysis was obtained from the results of the pretest and posttest of students using SPSS. Based on the results of the one-way ANOVA analysis, F-count 182.34 was obtained with a P-value (0.000 < 0.05) which means that there is a very significant difference in problem solving ability between the experimental class and the control class. The percentage score of problem solving ability at the logical solution level is 50% in the experimental class. While the percentage in the control class at the level of students' logical physics solutions is 0%. Students still have difficulty at the stage of connecting some physics concepts and determining solutions.

Geothermal anomalies on the eastern flank of the Cherokee basin, southeastern Kansas, USA

Bottomhole temperature measurements from oil and gas drilling in southeastern Kansas on the eastern flank of the Cherokee basin, in combination with a suite of about 2,200 differential temperature logs recently obtained from wireline logging in coalbed methane wells, define several higher-temperature anomalies at the top of the Mississippian Subsystem strata. Temperatures slightly in excess of 90 oF (35 oC) at depths of about 900 ft (275 m) correspond to geothermal gradients as high as about 60 oC/km.
 Sparse historical measurements of heat flow in the cratonic Cherokee basin indicate that the thermal anomalies are not likely caused by locally high heat flow. Heat flow in the Cherokee basin is probably in line with most other shallow cratonic basins. The higher-temperature thermal anomalies defined by logging temperatures do not correspond to previously mapped faults or other structural features in the Phanerozoic sedimentary section, but some anomalies are underlain by Precambrian basement lineations that are detectable with aeromagnetic and gravity measurements. Well-log determination of shale content in the Pennsylvanian sedimentary strata overlying the Mississippian limestones indicates that low thermal conductivity caused by higher shale content may cause some of the thermal anomalies. 
 Lateral (advective) movement of warmer, highly saline water from the basin axis cannot account for the anomalies because the anomalies are not characterized by exceptionally highly saline water in Mississippian strata. Similarly, recorded static fluid levels of wells disposing of oilfield saltwater into the Mississippian strata and the deeper Cambrian-Ordovician Arbuckle Group indicate that the deeper Arbuckle strata generally do not have sufficient formation pressure to force Arbuckle formation water upward into the Mississippian through either natural fractures or leaky wellbores. Small-scale changes in salinity, in combination with geologic structuring indicating faulting, make a case for vertical (convective) movement of heated, less saline water from the Arbuckle Group into overlying Mississippian limestones in isolated localities. Buoyancy of the Arbuckle formation water (due to temperature and salinity differences with the cooler and more saline Mississippian water) could also be the primary force behind the convection. Convergence of cooler freshwater moving westward off the Ozark dome and more saline basinal water moving eastward also could be a factor in defining the limits of some thermal anomalies.

Design and Validity of Interactive Multimedia Based on Cognitive Conflict on Static Fluid Using Adobe Animate CC 2019

This study aims to produce valid cognitive conflict-based interactive multimedia. This study uses the Plomp development model, which reports the results of the preliminary study and the prototyping phase. In the preliminary phase, five journals were analyzed and data were collected through teacher questionnaires. In the prototyping phase, multimedia is designed and self-evaluation is carried out and data collection is carried out through expert review questionnaires. The results of the journal analysis show that students' misconceptions about static fluid material are quite high. The results of the questionnaire show that learning is still teacher-centered, and interactive multimedia teaching materials are not yet available that can improve understanding of 4C concepts and skills. Based on the results of the preliminary research, in the prototyping phase, interactive multimedia based on cognitive conflict was designed using the Adobe Animate cc 2019 application. Interactive multimedia was arranged according to 4 syntaxes of cognitive conflict-based learning models, namely activation of preconceptions and misconceptions, presentation of cognitive conflicts, discovery of concepts and similarities, and reflection. . Each syntax is designed to improve students' conceptual understanding and 4C skills. The results of the interactive multimedia prototype self-evaluation obtained very good criteria. The results of the prototype validity test obtained a very valid category. Interactive multimedia has been valid in material substance, learning design, visual communication display, and software utilization.

Tolman-Ehrenfest-Klein law in non-Riemannian geometries

Heat always flows from hotter to a colder temperature until thermal equilibrium be finally restored in agreement with the usual (zeroth, first and second) laws of thermodynamics. However, Tolman and Ehrenfest demonstrated that the relation between inertia and weight uniting all forms of energy in the framework of general relativity implies that the standard equilibrium condition is violated in order to maintain the validity of the first and second law of thermodynamics. Here we demonstrate that the thermal equilibrium condition for a static self-gravitating fluid, besides being violated, is also heavily dependent on the underlying spacetime geometry (whether Riemannian or non-Riemannian). As a particular example, a new equilibrium condition is deduced for a large class of Weyl and f(R) type gravity theories. Such results suggest that experiments based on the foundations of the heat theory (thermal sector) may also be used for confronting gravity theories and prospect the intrinsic geometric nature of the spacetime structure.

Numerical analysis of velocity field and energy transformation, and prediction model for Taylor bubbles in annular slug flow of static power law fluid

Considering the rheological constitutive model and flow-control equation of the fluid around a Taylor bubble in an annulus, a prediction model of the flow field around the Taylor bubble is proposed. Combined with the flow-field distribution around a bubble, an energy-dissipation model for Taylor bubbles in an annulus is also established. Based on an analysis of the energy conservation, a unified prediction model for Taylor bubble migration in an annulus is developed by coupling the bubble-shape prediction model, flow-field prediction model around the bubble, and energy-dissipation model. Moreover, we independently develop a simulation program. Through a comparative analysis of the literature data, it was found that the prediction error of the migration velocity was less than 8%. The results of the energy dissipation demonstrate that the energy dissipation in the liquid-film region and fluid-viscosity dissipation are the key factors limiting the increase in bubble rising velocity.

Hyperbolically symmetric static charged cosmological fluid models

ABSTRACT In this work, the study on static fluid distributions under the influence of electromagnetism has been carried out with an emphasis on the hyperbolically symmetric metric. For this purpose, modified gravitational formulations in the presence of charge are used to calculate the effective energy–momentum tensor, which is then further refined by taking into account tetrad field components in the Minkowski coordinate system. Also, we compute the Tolman mass and a suitable formulation of the mass function. It exhibits that the hyperbolically symmetrical source has a negative effective matter density in all stellar formulations. This demonstrates that the quantum processes together with certain excessive constraints are deemed important to explain any physical implementations under the effects of the electromagnetic field. Additionally, we assessed the structure scalars and implemented the orthogonal splitting of the structure scalars and Riemann tensor in this modified gravity. Subsequently, various explicit precise cosmological solutions and their generating functions are developed.

Effect of wall modifications in a vortex shedding-based mechanical micromixer for heat/mass exchange

Despite the advances achieved to date in micromechanics, the resources needed to develop&test new designs may be a drawback for reduced scale engineering applications. In this sense, the use of computational tools allows to test multiple designs without the need to build a prototype physically and predict the performance of passive elements. The objective of the present paper is to test numerically the performance of different micro heat/mass exchanger designs composed by passive mechanical elements: a single pillar object leading to vortex shedding in the centre of a microchannel and microchannel wall modifications that can modify the detached oscillatory flow. To that aim, several side wall modifications (squared, triangular and circular cavities&protrusions) are tested. The final aim is to promote and enhance the thermal/molecular mixing promoted by the vortex shedding, thus increasing the homogeneity and the mixing efficiency. It is concluded that wall modifications with triangular cavities are able to increase the mixing efficiency more than a 2.3%. Also, this static fluid–structure interaction may boost/suppress vortex shedding, so it is important to predict the performance beforehand for any related application.

Anatomic Optical Coherence Tomography (aOCT) for Evaluation of the Internal Nasal Valve.

To establish the utility of anatomic optical coherence tomography (aOCT) in evaluating internal nasal valve (INV). Anatomic specimen imaging study. Fresh-harvested human specimen heads were evaluated using both computed tomography (CT) imaging as well as using aOCT. Scans were performed at three time points: 1) After septoplasty for cartilage harvest, 2) after placement of butterfly graft (BFG), and 3) after placement of bilateral spreader grafts (SG). Imaging data were then converted into 3D models of the nasal airway. CT- and aOCT-generated models were compared by both static volumetric analysis and computational fluid dynamics (CFD) to predict nasal resistance and pressure. Scans using aOCT showed comparable results to CT in terms of volumetric parameters both before and after intervention. Analysis of aOCT data by CFD demonstrated decrease in pressure after SG or BFG intervention. No statistically significant difference was observed when comparing CT- and aOCT-generated calculations of pressure or resistance. The INV can be imaged in a static fashion using aOCT technology. Advantages over traditional CT imaging include lack of exposure to radiation and rapid scan time. In addition, in-office use is possible as aOCT technology develops. Further investigation will be necessary to define the role of aOCT in the dynamic evaluation of this vital component of the nasal airway. 3 Laryngoscope, 132:2148-2156, 2022.

On Minimal Hypersurfaces of a Unit Sphere

Minimal compact hypersurface in the unit sphere Sn+1 having squared length of shape operator A2<n are totally geodesic and with A2=n are Clifford hypersurfaces. Therefore, classifying totally geodesic hypersurfaces and Clifford hypersurfaces has importance in geometry of compact minimal hypersurfaces in Sn+1. One finds a naturally induced vector field w called the associated vector field and a smooth function ρ called support function on the hypersurface M of Sn+1. It is shown that a necessary and sufficient condition for a minimal compact hypersurface M in S5 to be totally geodesic is that the support function ρ is a non-trivial solution of static perfect fluid equation. Additionally, this result holds for minimal compact hypersurfaces in Sn+1, (n>2), provided the scalar curvature τ is a constant on integral curves of w. Yet other classification of totally geodesic hypersurfaces among minimal compact hypersurfaces in Sn+1 is obtained using the associated vector field w an eigenvector of rough Laplace operator. Finally, a characterization of Clifford hypersurfaces is found using an upper bound on the integral of Ricci curvature in the direction of the vector field Aw.

Pengembangan Media Pembelajaran E-Mind Mapping Berbasis Flipbook pada Mata Pelajaran Fisika SMA Kelas 11

This development research aims to produce an E-Mind Mapping learning media based on flipbook physics for grade 11 high school students on equilibrium and rotational dynamics, elasticity and Hooke's law, as well as static and dynamic fluids. This research is a development research (R&D) using the R2D2 (Recursive, Reflective Design and Development model) model with the stages, namely, determining learning materials, analyzing needs, developing learning materials, compiling E-Mind Mapping concepts, editing materials into. e-learning. mind mapping and combining it into a flipbook, production, validation and testing, revision and refinement. However, in this study, it was only carried out until the validation stage. The results of the study show that the material displayed in this flipbook-based E-Mind Mapping has met the eligibility criteria in the very good category, and the flipbook-based E-Mind Mapping learning media has met the eligibility criteria in the good category. Overall, the flipbook-based E-Mind Mapping learning media has met the eligibility criteria in the good category.

Static Perfect Fluid Space-Time on Almost Kenmotsu Manifolds

In this work, we intend to investigate the characteristics of static perfect fluid space-time metrics on almost Kenmotsu manifolds. At first we prove that if a Kenmotsu manifold $M$ is the spatial factor of static perfect fluid space-time then it is $\eta$-Einstein. Moreover, if the Reeb vector field $\xi$ leaves the scalar curvature invariant, then $M$ is Einstein. Next we consider static perfect fluid space-time on almost Kenmotsu $(\kappa,\mu)'$-manifolds and give some characteristics under certain conditions.

Trans-Sasakian static spaces

Static spaces (with perfect fluids) appeared in a natural way both in physics (cf. Hawking and Ellis, 1975) and mathematics (cf. A. Fischer and J. Marsden, Duke Math. J. 42 (3) (1975), 519–547). These arise as solutions of the perfect static fluid equation and play a key role in general relativity, providing patterns for some celestial objects. In this paper, we investigate compact and simply connected trans-Sasakian spaces having type (α,β), whose defining functions α and β satisfy the static perfect fluid equation. In particular, we derive some conditions that ensure these spaces are isometric to a 3-sphere. First result of this work shows that the function α satisfying static perfect fluid equation and the scalar curvature τ satisfying certain inequality are not only necessary, but also sufficient conditions for a 3-dimensional compact and simply connected trans-Sasakian manifold to be isometric to a 3-sphere. In the second result of this paper, we prove that the function β satisfying the static perfect fluid equation, scalar curvature τ satisfying certain inequality and the Ricci operator satisfying a Coddazi-type equation are also requirements ensuring that a trans-Sasakian space (again compact and also simply connected) is isometric with a 3-sphere.

Analysis of Students' Conceptual Understanding of Physics on the Topic of Static Fluids

Physics misunderstandings still occur in high school students now. Therefore, it requires complete learning so that students' conceptual physics can be stable and embedded in everyone. This study aimed to diagnose the extent to which students' conceptual understanding of physics on the topic of static fluid is. This study used a survey approach to form a written test for 100 senior high schools in two schools in Central Maluku Regency. The results showed that there were still many students who experienced fluid misconceptions in cases 2, 3, and 5 to achieve a good level. Therefore, deep learning is needed so that students' conceptual physics will be good and not forgotten