Mixing Phenomena Research Articles

CODE SWITCHING DAN CODE MIXING PADA NOVEL CRYING WINTER KARYA MELL SHALIHA

The purpose of this study describes the types of code switching and code mixing in Mell Shaliha Crying Winter novel and the factors that cause code switching and code mixing. The method used in this research is qualitative method. This study uses a qualitative method. Data collection is done by observation and note-taking. The results of this study explain that code switching and code mixing events in the novel Crying Winter are found, namely internal and external code switching in the form of English into Indonesian and vice versa, Korean into Indonesian and the phenomenon of code mixing in the form of words, phrases, baster and clauses. The factors that influence the existence of code switching and code mixing are the participants, the situation, and the influence of the previous speech, and the aims of the conversation.

Developing PCC and DCC integral effects test experiments at the High Temperature Test Facility

Among the Next-Generation Nuclear Plant (NGNP) designs, the High-Temperature Gas-Cooled Reactors (HTGRs) are very attractive, due to their inherent safety features, high power conversion efficiency, and potential of providing high-temperature process heat. To perform a thorough safety study and to license these types of reactors, sufficient information needs to be provided about the phenomena that occur during accident scenarios. While several experimental research efforts have been dedicated in the past to investigate accident scenarios, knowledge gaps still exist in the phenomena characteristic of pressurized and depressurized conduction cooldown (PCC/DCC) transients as well as for normal operation scenarios. This paper summarizes the Oregon State University High Temperature Test Facility (HTTF) test matrix, experimental campaign, and selected tests results. High Temperature Test Facility is a scaled Integral Test Facility (IET) that is capable of mimicking scaled dimensions and operational conditions of the Modular High-Temperature Gas Cooled Reactor (MHTGR). The goal of the High Temperature Test Facility is to provide experimental data on the DCC, PCC and normal operating scenarios of the reference Modular High-Temperature Gas Cooled Reactor design. The DCC, PCC, mixing, heat up and cooldown tests described in this paper were performed at prototypical Modular High-Temperature Gas Cooled Reactor temperatures, scaled initial pressure conditions (∼200 kPa), and thermal power input of less than 70 kW. Presented test data show temperature distributions in the High Temperature Test Facility core, upper plenum, cross duct, or lower plenum. Based on these temperature profiles attempts to investigate stratified flow, natural convection flow, heat up, cooldown and mixing phenomena are made. Furthermore, this paper evaluates the performed test campaign in the light of the Very High Temperature Gas-cooled Reactor Phenomena Identification and Ranking Table (PIRT) and proposes experiments to complement the existing PCC/DCC testing database for the validation of the thermal-hydraulic codes.

Large-eddy simulation on two-liquid mixing in the horizontal leg and downcomer (the TAMU-CFD Benchmark), with respect to fluctuation behavior of liquid concentration

Pressurized Thermal Shock (PTS) is induced potentially by the rapid cooling of the cold-leg and downcomer wall in the primary system of a Pressurized Water Reactor (PWR) due to the initiation of Emergency Core Cooling System (ECCS). Thus, fluids mixing in a horizontal cold-leg and downcomer should be predicted accurately. However, turbulence production and damping often hinders this prediction due to the presence of the density gradients. Hence, the Fifth International Benchmark Exercise, “the cold-leg mixing Computational Fluid Dynamics (CFD) Benchmark,” was conducted under the support of OECD/NEA. The experiment was designed for visualization of the mixing phenomena of two liquids with different densities. The heavy liquid was a simulant of cold water from ECCS, in a horizontal leg and downcomer. We used the Large-eddy Simulation (LES) to investigate the time fluctuation behaviors of velocity and liquid concentration. The CFD simulation was performed with two turbulence models and three different numerical meshes. We investigated the characteristics of the appearance frequency of the heavy liquid concentration with the statistical method. Based on our findings, we propose further experiments and numerical investigations to understand the fluid mixing phenomena related to PTS.

Inverse Design of Nonlinear Polaritonic Metasurfaces for Second Harmonic Generation

Enabling strong nonlinear optical phenomena requires carefully designed photonic devices to maximize light–matter interactions. In recent years, topology optimization has become an increasingly popular tool to optimize photonic devices, due to its efficiency in dealing with extremely large parameter spaces. The focus has largely been on two-dimensional linear optical devices, particularly in integrated photonic settings, with a limited number of studies extending topology optimization to nonlinear effects in dielectric structures. Here, we apply topology optimization to metal–multiple quantum well–metal structures supporting intersubband transitions. In past years, the combination of photonic engineering and material design has enabled extremely efficient ultrathin second harmonic generating metasurfaces, based on L- and T-shaped resonators. Topology optimization enables novel designs that exceed the state-of-the-art nonlinear metasurfaces to date, with the promise of further improvement. The same approach may be extended to other frequency mixing phenomena, such as sum-frequency or difference-frequency generation.

APPEARANCES OF CODE SWITCHING AND CODE MIXING IN ONLINE CONVERSATION

Code switching and code mixing are occurred due to phenomena of bilingualism and multilingualism in communication activity. The use of code switching and code mixing are generally used when people talk to each other with friends, family, or other people. This study aimed to analyze the types of code switching by Poplack (1980) such as Intra sentential, Inter sentential and Extra sentential and code mixing by Muysken (2000) which consists of Insertion, Alternation and Congruent lexicalization which is occurred in the conversation in the conversation between Najwa Shihab and Maudy Ayunda in the “Catatan Najwa” Youtube channel. This study also analyzed type of reasons of code switching and code mixing occurred in the conversation. The mixes of qualitative and quantitative method were used by the researcher. The results of the study showed that the phenomena of code switching and code mixing appeared a lot in conversation between Najwa Shihab and Maudy Ayunda.

Strong effect of fluid rheology on electrokinetic instability and subsequent mixing phenomena in a microfluidic T-junction

When two fluids of different electrical conductivities are transported under the influence of an electric field, the electrokinetic instability (EKI) phenomenon often triggers in a microfluidic device once the electric field strength and conductivity gradient exceed some critical values. This study presents a detailed numerical investigation of how the rheological behavior of a fluid obeyed by the non-Newtonian power-law constitutive relation could influence this EKI phenomenon in a microfluidic T-junction. We find that as the fluid rheological behavior changes from shear-thickening (n >1) to shear-thinning (n <1), the EKI phenomenon is significantly influenced under the same conditions. In particular, the intensity of this EKI phenomenon is found to be significantly higher in shear-thinning fluids than in Newtonian and shear-thickening fluids. Also, the critical value of the applied electric field strength for the inception of this EKI phenomenon gradually increases as the fluid rheological behavior progressively moves from shear-thinning to shear-thickening. The corresponding mixing phenomenon, often achieved using this EKI phenomenon, is also notably higher in shear-thinning fluids compared to Newtonian and shear-thickening fluids. A detailed analysis of both the flow dynamics and mixing phenomena inside the microdevice is presented and discussed in this study. To perform so, we also employ the data-driven dynamic mode decomposition technique, considered one of the widely used reduced-order models to analyze a dynamical system. This analysis facilitates a better understanding of the EKI-induced chaotic convection and mixing phenomena inside the microdevice. We observe that the spatial expanse and intensity of the coherent flow structures differ significantly as the power-law index changes, thereby providing valuable insight into certain aspects of the underlying flow dynamics that, otherwise, are not apparent from other analyses.

Segregation of water and gravel using large ball mill device laid roughness bed

This paper presents an experimental approach to study the phenomena of segregating water and gravel using a large ball mill device that reproduces segregation phenomena under debris flow. First, the experiment was conducted in a ball mill device under various conditions: water and gravel mixing, bed velocity, and laid roughness. The occurrence conditions of the segregation phenomena of water and gravel mixing are categorized and compared with each other with and/or without roughness on the bed. Furthermore, the movements after water and gravel mixing in the ball mill device are observed to investigate the segregation mechanism.

NUMERICAL ANALYSIS OF APPARATUS-INDUCED DISPERSION FOR DENSITY-DEPENDENT SOLUTE TRANSPORT IN POROUS MEDIA

AbstractThe effects of apparatus-induced dispersion on nonuniform, density-dependent flow in a cylindrical soil column were investigated using a finite-element model. To validate the model, the results with an analytical solution and laboratory column test data were analysed. The model simulations confirmed that flow nonuniformities induced by the apparatus are dissipated within the column when the distance to the apparatus outlet exceeds $3R/2$ , where R represents the radius of the cylindrical column. Furthermore, the simulations revealed that convergent flow in the vicinity of the outlet introduces additional hydrodynamic dispersion in the soil column apparatus. However, this effect is minimal in the region where the column height exceeds $3R/2$ . Additionally, it is found that an increase in the solution density gradient during the solute breakthrough period led to a decrease in flow velocity, which stabilized the flow and ultimately reduced dispersive mixing. Overall, this study provides insights into the behaviour of apparatus-induced dispersion in nonuniform, density-dependent flow within a cylindrical soil column, shedding light on the dynamics and mitigation of flow nonuniformities and dispersive mixing phenomena.

MACROSCOPIC SPRAY CHARACTERISTICS OF GASOLINE, METHANOL, AND ETHANOL IN DIRECT INJECTION SPARK IGNITION ENGINE-LIKE CONDITIONS

In recent decades, stringent emission norms have been enforced upon the engine research community and OEMs to encourage them to develop new spark ignition engine technologies, such as variable valve lifts, turbocharging, and direct injection spark ignition (DISI) engines. For further development, greater control of parameters such as in-cylinder air motion, spray characteristics, injection, and ignition events is required. Spray characterizations are crucial for understanding the mixing phenomena in heated and pressurized engine combustion chamber conditions. Spray pattern, fuel injection pressure (FIP), rate shape, and thermodynamic conditions of the combustion chamber play a vital role in the mixture preparation. The present study uses Mie-Scattering techniques to examine spray structures of fuels like methanol and ethanol and compare them to gasoline, which is of great interest to DISI engines. Three different temperatures of 50, 100, and 200°C and two chamber pressures, 4 and 8 bar, are considered to simulate typical engine-cylinder conditions. It is observed that the initial chamber conditions greatly influence the spray structure. Spray collapse is lesser for alcohol than gasoline. Three semi-empirical models for predicting spray penetration are analyzed: Dent, Hiroyasu and Arai, and Arrègle. These models could not differentiate between the test fuels, particularly methanol and ethanol, for predicting spray penetration length. The degree of deviation in predictions is the lowest in the Hiroyasu and Arai model and the highest in the Dent model. Spray penetration length increased with an increasing FIP regardless of ambient conditions; however, the spray penetration length decreased with increasing chamber pressure.

The effect of different carrier fluids on heat transfer performance in a microfluidic serpentine device

In this work, the efficiency of heat transfer and the related fluid-mechanic performance inside a microfluidic device are investigated by varying the type of carrier fluid at different flow rates. The experimental analysis has been conducted on a serpentine channel configuration by considering five different fluid mixtures. The results displayed and emphasized the relevant role of viscosity on thermal performance in the laminar regime. The corresponding Nusselt number values have been identified in terms of Reynolds and Prandtl numbers. Specifically, high-viscosity mixtures exhibited Nusselt number values strongly correlated with Prandtl number. So far, heat transfer for these mixtures is improved as a result of the greater extent of the thermal entrance region and of the higher thermal gradient. Nusselt-Reynolds trends for such mixtures also presented a consistent rate of increase, this increment being however severely limited by the action of viscous dissipation as Reynolds number increases. On the other hand, mixtures with low viscosity showed high correlation between Nusselt and Reynolds numbers. The importance of local turbulence phenomena for such low-viscosity fluids becomes one of the main factors in heat transfer enhancement, also for small-scale thermal sinks in laminar regime. In fact, for such mixtures, thermal performances are incremented by the combining effects of local mixing phenomena at each bend of the serpentine and by the increasing extension of the thermo-hydraulic development region.

Modeling and LES of high-pressure liquid injection under evaporating and non-evaporating conditions by a real fluid model and surface density approach

Numerical modeling of high-pressure liquid fuel injection remains a challenge in various applications. Indeed, experimental observations have shown that injected liquid fuel jet undergoes a continuous change of state from classical two-phase atomization and spray droplets evaporation to a dense-fluid mixing phenomenon depending on the ambient pressure, temperature, and fuel properties. Accordingly, a predictive and efficient computational fluid dynamics (CFD) model that can represent the possible coexistence of subcritical and supercritical regimes during the fuel injection event is required. The widely used Lagrangian Discrete Droplet Method (DDM) requires parameter tuning of model constants and cannot model the dense near-nozzle region. Meanwhile, the high computational cost of Interface Capturing Methods (ICM) has prohibited their application to industrial cases. Thus, another alternative is an Eulerian Diffuse Interface Model (DIM), where the unresolved interface features are modeled instead of being tracked. Accordingly, the current work proposes a fully compressible multi-component two-phase real-fluid model (RFM) with a diffused interface and closed by a thermodynamic equilibrium tabulation method based on a real-fluid equation of state. The RFM model is complemented with a postulated surface density equation for fuel atomization modeling within the Large Eddy Simulation (LES) framework. The Engine Combustion Network (ECN) Spray A injector non-evaporating and nominal evaporating conditions are used as a reference for the proposed model validation. Simulations are performed using the proposed RFM model that has been implemented in the CONVERGE CFD solver. Under the non-evaporating condition, the RFM model can capture well the fuel mass distribution in the near-nozzle field, but also the interfacial surface area. Besides, the predicted drop size from simulations falls within the experimental data range. On the other hand, under the evaporating condition, spray liquid and vapor penetrations and fuel mixture fraction distribution are also accurately predicted. The vaporization effect on the surface area density is revealed to enhance surface generation in the dense spray region while reducing the surface density in the dilute spray region. The mean droplet size is also relatively reduced under the evaporating condition in the diluted spray region. Overall, the accuracy and computationally efficiency of the proposed RFM model coupled with the surface density equation for high-pressure fuel injection modeling are confirmed, allowing its use for high pressure industrial configurations in future studies.

Obtaining Niobium Nitride on n-GaN by Surface Mediated Nitridation Technique

In this work the n-GaN(1000) surface is used as a source of nitrogen atoms in order to obtain niobium nitride film by a surface-mediated nitridation technique. To this end, the physical vapor deposition of the niobium film on GaN is followed by sample annealing at 1123 K. A thermally induced decomposition of GaN and interfacial mixing phenomena lead to the formation of a niobium nitride compound, which contains Nb from thin film and N atoms from the substrate. The processes allowed the obtaining of ordered NbNx films on GaN. Structural and chemical properties of both the GaN substrate and NbNx films were studied in-situ by surface-sensitive techniques, i.e., X-ray and UV photoelectron spectroscopies (XPS/UPS) and a low-energy electron diffraction (LEED). Then, the NbNx/GaN surface morphology was investigated ex-situ by scanning tunneling microscopy (STM).

Latitudinal and archipelago effect on the composition, distribution, and abundance of zooplanktonic organisms in the Gulf of California

The upper Gulf of California is one of the most energetic regions owing to its tidal range and strong tidal currents, making the upper gulf and the archipelago zone highly turbulent regions; the abundance of zooplankton should be associated with mixing phenomena. We aimed to determine the latitudinal distribution of zooplanktonic organisms in this region and the influence of the islands on their distribution and abundance using historical data. Distribution of abundance followed the current patterns, the archipelago influences abundance favorably but does not affect diversity. Latitudinal zooplankton richness had a quasi-parabolic shape. A decrease in richness was observed at 27.5°N, in the archipelago region, with maximum richness at 26.5°N and 28.5°N. The distribution of latitudinal ranges is consistent with geometric constraints models; taxa with wide ranges are in the central area, while those with narrow ranges are near the boundaries and the Upper Gulf. Zooplankton responds in some way to the existence of the southern boundary as shown by the decrease of richness in this region. At the whole scale of the Gulf, the distribution of richness followed geometric constraints model, while at smaller scales, distribution and abundance are conditioned by the hydrodynamics of the Gulf. We compared zooplankton spatial distribution with Sea Level Anomaly, Sea Surface Temperature, and Chlorophyll-a concentrations from Copernicus to establish relationships between these factors. We performed Cluster and Redundancy Analysis to characterize similarities between stations in terms of biomass and taxon composition and to assess the importance of environmental variables on the distribution of zooplankton.

Numerical study on temperature distribution and mixing effect by spacer grid in 2×1 subchannel

A major function of Mixing Vane Grids (MVGs) in Light Water Reactors (LWRs) is mixing. Strong mixing results in more uniform coolant temperature distribution, which often leads to improvement in Critical Heat Flux (CHF). In subchannel analysis, a typical mixing coefficient β is often used to represent MVG mixing performance. Despite of this, due to the periodical mixing caused by MVGs with complex geometry under a wide range of operating conditions, a simple constant mixing coefficient cannot accurately reflect the true characteristics of MVG. In order to explore the fundamental mixing characteristics introduced by mixing vanes, a 2×1 subchannel system was selected to study the mixing mechanism. Due to the wall effect, different boundary settings in the 2×1 subchannel gaps were analyzed and compared with 5×5 simulation results to get the most similar simulation results. To evaluate the effect of grids on mixing, the temperature distributions and thermal non-uniformity (Et) between bare rod bundles and grid-enclosed rod bundles were compared. A new concept of local mixing and subchannel mixing was proposed, by comparing the local Et (defined based on mesh size used in CFD calculation), the subchannel Et (defined based on the subchannel area) and temperature contours. In subchannel analysis, lumped parameters could not accurately represent the true mixing caused by mixing vanes. They overestimated the mixing effect and neglected the important near wall mixing phenomenon.

ALIH KODE DAN CAMPUR KODE INTERAKSI GURU DAN SISWA DI SMK NEGERI 1 PALU

This research is titled: ‘’Code Switching and Code Mixing Teacher and Students Interaction at SMK Negeri 1 Palu’’. The objectives of this study are (1) to describe the form of code switching and code mixing in teacher and student interactions at SMK Negeri 1 Palu, (2) to know function of code switching and code mixing, (3) to describe the factors that influence code switching and code mixing in teacher and student interactions during the learning process teach in the class. This research was conducted at SMK Negeri 1 Palu with the research subject being an English teacher. The research is focused on the phenomenon of code switching and code mixing in the interaction of teachers with students during teaching and learning in the classroom and the factors that influence them. The results of the study show that: (1) the form of teacher code switching consists of two parts, namely the language used in communication consists of formal and informal. In addition, the relationship between languages is in the form of code switching form English-Indonesian and Indonesian-English, (2) the functions code switching and code mixing in interaction teacher with students, (3) The factors that influence code switching and code mixing are the realitonship between the speaker and the speech partner, the change in the situasion from formal to informal or vice versa, and changes in the topic of conversation

Linguistic Hybridity: The Use of Code Mixing in Nepali Folk Pop Songs

Code mixing of two or more languages has become a common phenomenon in Nepali folk pop songs. In this context, this study discussed the phenomenon of mixing multilingual terms in Nepali folk pop songs and the reasons for mixing such codes from other languages. This qualitative phenomenological study along with situation analysis used documents and unstructured interviews as the data collection tools. I selected 12 Nepali folk pop songs purposively for analysis. They include Baduliko Khutko (“Sound of a Hiccup”), Champa (“Champa girl”), “Hello Hello”, Meri Chhoretti (“My Girl Friend”), Mudda Haldincchu (“File a Case”) and Rato Rato Khursani Piro Chha (“Red, Red Pepper Hot”), Chorut Salkauane (“Light a Cigarette”),“Cocacola Figure” and DJ Bajako (“Playing DJ”), Daru Sadkaune (“Gulping Local Wine”) and Hi Kali (“Hello Beauty”), and Tension Naleu Yaar (“Don’t be in Tension, Friend”). These songs were played in the audio laboratory to identify the multilingual terms used by the Nepali composers and musicians in Nepali folk pop songs and analyzed in terms of the phenomenon of code mixing. Two language teachers and one folk pop singer were interviewed to explore the reasons for code mixing. The result shows that the young generation is mostly attracted towards the folk pop songs with code mixing, and such songs become popular among the youths due to their multilingual flavour. Nepali folk songs have been influenced by the postmodernist tradition, fashion and technological influence. The trend of code mixing in Nepali folk pop songs may lose the linguistic purity thereby resulting linguistic hybridity.

Computer Vision for Kinetic Analysis of Lab- and Process-Scale Mixing Phenomena.

A software platform for the computer vision-enabled analysis of mixing phenomena of relevance to process scale-up is described. By bringing new and known time-resolved mixing metrics under one platform, hitherto unavailable comparisons of pixel-derived mixing metrics are exemplified across non-chemical and chemical processes. The analytical methods described are applicable using any camera and across an appreciable range of reactor scales, from development through to process scale-up. A case study in nucleophilic aromatic substitution run on a 5 L scale in a stirred tank reactor shows how camera and offline concentration analyses can be correlated. In some cases, it can be shown that camera data hold the power to predict reaction progress.

Engineering a monolithic 3D paper-based analytical device (μPAD) by stereolithography 3D printing and sequential digital masks for efficient 3D mixing and dopamine detection

Stereolithography 3D printing and digital masks in sequence are used herein to manufacture 3D µPAD in a monolithic layer of paper within 1 s. Multiple experiments were systematically conducted to further understand the fundamentals and limitation of this manufacturing process, and a novel 3D mixer and a fluorescent chemosensor assay used to determine dopamine concentration at high-alkaline pH conditions were successfully demonstrated. Experiment results showed: (1) the 3D mixer is superior than conventional 2D mixer regarding mixing performance and repeatability, (2) dopamine detection and pH indicator can be realized with fewer operation steps and shorter processing time, (3) a truly 3D µPAD, including multilayer microchannels within a monolithic paper substrate, can be created with fewer reagent loss and higher transportation efficiency, (4) a smallest microchannel, 100 µm wide microchannel, can be successfully created on µPAD. These results clearly proved that this proposed 3D µPAD is not only a novel format of µPAD, but it can also simplify the operation steps for an analytical assay while improving the mixing phenomenon via 3D mixer and using minimum sample volume. • Using SLA 3D printing and multiple digital masks to manufacture monolithic 3D µPAD. • 3D mixer is superior than 2D mixer regarding mixing performance and repeatability. • A truly 3D µPAD can result fewer reagent loss and higher transportation efficiency. • Dopamine detection and pH indicator can be realized with fewer operation steps. • A smallest microchannel, 100 µm wide microchannel, was successfully created.

Swirling main flow effects on film cooling: Time resolved adiabatic effectiveness measurements in a gas turbine combustor model

Lean burn swirl stabilized combustors represent the key technology to reduce NOx emissions in modern aircraft engines. The high amount of air admitted directly trough the injection system and the higher levels of pressure and temperature requested by the engine cycle make the design of even more efficient cooling systems and the correct estimation of combustor liners heat load a crucial task for the combustor durability. One of the technologies used for the cooling of these components is the effusion cooling, which promotes the formation of a cold layer to protect the liner walls, whose cooling capabilities are described with the adiabatic effectiveness parameter. The effectiveness of these systems is severely influenced by the swirling flows generated by the swirler injectors which promote the mixing between cold and the hot gases of the combustion process. The development of the swirling flow structures inside the combustor chamber and the grade of interaction between swirling flow and the liner walls can be described by the swirl number (SN). In order to investigate the impact of the effects of the SN parameter on the adiabatic film effectiveness, a dedicated non-reactive single-sector linear combustor test rig was designed and equipped with three different axial injectors (SN=0.6−0.8−1.0) and a cylindrical holes effusion plate to simulate the liner cooling system. Film effectiveness was acquired using Fast response Pressure Sensitive Paint (FPSP) technique; the scale of the model and the acquisition frequency of 1 kHz allowed to track the effusion jets and main flow interactions. The collected results show the importance of using an unsteady analysis to perform an in-depth characterization of the mixing phenomena between the main flow and the coolant which are significantly affected by the swilring characteristics.

Investigation of nonlinear torsional guided wave mixing in pipes buried in soil

Pipes have been widely applied in different engineering areas, such as drainage and the conveyance of chemical products and they are usually installed underground. This makes the structural integrity inspection becomes challenging. Numerous studies investigated the phenomenon of guided wave propagation in buried pipes and the wave interaction with different types of damage, e.g. corrosion and thermal damage. However, very limited studies focused on studying guided wave mixing in embedded pipes, which has recently attracted significant research interest for damage detection. This study develops a three-dimensional (3D) finite element (FE) model incorporating strain energy function to analyse wave mixing phenomena in pipes embedded in the soil. To characterise nonlinear features, such as combinational harmonic generation, due to guided wave mixing, the 3D FE model is used to simulate two torsional guided waves interacting with each other. The numerical results are then verified by experimentally measured data and the results show that the amplitude in the frequency-domain exhibits a sharp drop due to the energy leakage in the existence of soil medium at fundamental frequencies, second and combinational harmonics.