Streamline Research Articles

Studi Karakteristik Tailing Pada Lokasi Eks Penambangan Timah di Bukit Sambung Giri Kecamatan Merawang Kabupaten Bangka

Tailing deposits at ex-tin mining area in Bangka and Belitung Island has a large number of economical
 residual minerals. This study is to identify tailing characteristic and its potential mineralogy and
 elements based on shallow hand boring (Auger) samples, along stream line in west part of Sambung
 Giri Hill. Every coordinate sample plotted on base map. Loboratory analisys using Strereo
 Mikroscope for identify minerals characteristics, and geochemical analysis using XRF for identification
 the presence of elements. The tailing deposits has laterally grain size gradation to down stream,
 composed above 94% sand fraction, and small amount of shale and granule fraction. Quartz mineral
 presence more then 90%, followed by iron oxide (hematite), clay, zircon, cassiterite, ilmenite, monazite
 and tourmaline minerals, showed low consistency in lateral spatial exept quartz, with its Rare Earth
 Elementh (REE) composition is Cerium (Ce), Lanthanum (La), Yttrium (Y), Neodymium (Nd) and
 Samarium (Sm).

Interannual Anomaly in Tropical Cyclone Frequency Around Korea by Western North Pacific Monsoon

ABSTRACT In this study, the correlation between the frequency of summer tropical cyclones (TC) affecting areas around Korea over the last 37 years and the western North Pacific monsoon index (WNPMI) was analyzed. A clear positive correlation existed between the two variables, and this high positive correlation remained unchanged even when excluding El Nino-Southern Oscillation (ENSO) years. To investigate the causes of the positive correlation between these two variables, ENSO years were excluded, after which the 8 years with the highest WNPMI (strong WNPM phase) and the 8 years with the lowest WNPMI (weak WNPM phase) were selected, and the average difference between the two phases was analyzed. In the strong WNPM phase, TCs usually occurred in the eastern waters of the tropical and subtropical western North Pacific, and tended to pass the East China Sea on their way north toward Korea and Japan. In the weak WNPM phase, TCs usually occurred in the western waters of the tropical and subtropical western North Pacific, and tended to pass the South China Sea on their way west toward the southeastern Chinese coast and the Indochina peninsula. Therefore, TC intensity was higher in the strong WNPM phase, during which TCs are able to gain sufficient energy from the sea while moving a long distance to areas nearby Korea. TCs also tended to occur more often in the strong WNPM phase. In the difference between the two phases regarding 850 hPa and 500 hPa streamline, anomalous cyclones were reinforced in the tropical and subtropical western North Pacific, while anomalous anticyclones were reinforced in mid-latitude East Asian areas. Due to these two anomalous pressure systems, anomalous southeasterlies developed in areas near Korea, with these anomalous southeasterlies playing the role of anomalous steering flows making the TCs head toward areas near Korea. Also, due to the anomalous cyclones developed in the tropical and subtropical western North Pacific, more TCs could occur in the strong WNPM phase.

Numerical study of unsteady MHD flow of Williamson nanofluid in a permeable channel with heat source/sink and thermal radiation

The present research work is dedicated to examine the heat and mass transport phenomenon due to unsteady MHD flow of Williamson nanofluid between the permeable channel with heat source/sink. The influence of buoyancy and thermal radiation effects are also considered for the present model. The flow equations are reduced to an equivalent nonlinear coupled partial differential equations (PDE) through suitable transformation. The numerical simulation is performed to attain the solution of the nonlinear system via the Crank-Nicolson finite difference scheme. The influence of various emerging parameters on velocity, temperature and concentration profiles are developed. The magnetic parameter plays the significant role to enhance the heat transfer rate but reduces the velocity profile. The velocity of the fluid increases gradually with respect to time and this influence is dominant at the center of the channel. Additionally, the velocity profile exhibits the increasing behavior by varying the Reynolds number for a small time. In the entire study it is analyzed that the temperature profile increases for increasing values of Reynolds, thermophoresis, Brownian motion and heat source numbers, while a low temperature profile is attained for Biot numbers. The thermophoresis and Brownian motion parameters provide the decreasing concentration profile however, an increasing result is noticed for Biot numbers. An increase in the values of Williamson parameter $ \Lambda$ , illustrates the increase effects on the skin friction coefficient when $ \eta=1$ while it shows the decrease behavior at $ \eta=0$ . The effects of the Reynolds number on streamlines pattern is presented. It is noticed that the higher values of Re affects the stream line pattern.

Computational studies on passive containment isolation system of AHWR

The Advanced Heavy Water Reactor (AHWR) incorporates several passive safety systems. Passive containment isolation system (PCIS) is one of such passive system, which is designed to prevent release of radioactivity to environment in the event of accidents such as Loss of Coolant Accident (LOCA) or Main Stream Line Break. PCIS isolates the reactor containment from atmosphere by making a water seal in ‘U’ shaped ventilation duct using the differential pressure between containment and atmosphere. This paper deals with Computational Fluid Dynamics (CFD) simulation of PCIS using Volume of Fluid (VOF) approach using OpenFOAM CFD code. CFD model is validated using Passive Containment Isolation Experimental Facility and dam break problem. CFD simulations are performed for PCIS of AHWR for 2%, 20%, 100% and 200% break size LOCA and estimated the time of isolation and amount of water transfer to ‘U’ duct. CFD result shows that PCIS of AHWR performed its intended work for all LOCA break sizes.

Indicators for contaminant transport in a periodical wind-driven wetland flow

Understanding indicators for contaminant transport in wetlands under wind is essential to agricultural pollution assessment associated with chemical fertilizers and pesticides. Presented in this paper is an analytical study of indicators for contaminant transport in a periodical wind-driven wetland flow. Analytical solutions of velocity profile, total quantity of contaminant in a streamline, position and moving velocity of mass center of contaminant cloud, and environmental dispersivity are rigorously derived and analyzed for a typical wetland flow under the combined action of periodical wind stress and superficial pressure gradient. It is found that the flow direction changes alternatively only for a large oscillatory wind stress. For instantaneous emission of multiple point sources, the total quantity of contaminant in each stream line parallel to the free surface is dependent on the initial distribution of contaminant only in the initial stage and eventually reaches a constant. For long time evolution of contaminant cloud, the mass center of contaminant cloud oscillates periodically around the origin of a coordinate system moving at a speed of the mean value of depth-averaged velocity during one period, and corresponding oscillatory amplitude enhances with the increasing oscillatory wind stress. The amplitude of environmental dispersivity increases with the increase of oscillatory wind stress, and negative environmental dispersivity appears for partial time in an oscillatory period for a large oscillatory wind stress.

역류 방지형 초저온 체크밸브의 유동해석에 관한 연구

As part of reducing environmental pollutants by recent fossil energy, use of natural gas is gradually increasing. Since the pollution materials generated during combustion as compared to the fossil energy contains less worldwide, LNG consumption has been increasing rapidly. Cryogenic check valves to be used in the LNG carrier are dependent on imports for the total amount so that it needs domestic production. Back flow prevention check valve is located in the flow of the linear fluid. It is opened when the flow direction is forward. When the flow is reversed, the valve is automatically closed by back pressure. A number of studies relating to the shape and internal flow of the check valves have been conducted since they are used in the general industrial applications. However, there are hardly any fluid engineering studies in internal flow field for the case for cryogenic temperature check valves. Therefore, the purpose of this study is obtain the coefficient of flow meter and pressure drop values to develop a check valve for cryogenic back flow prevention for LNG by analyzing the pressure distribution, velocity distribution, and stream line distribution inside the valve through the flow analysis according to the flow rate of the valve. This study also intends to provide the basic design data of the check valve for the cryogenic temperature check.

Leaders’ Emotions and Followers’ Behaviors: A New Perspective with Perceived Emotional Sincerity

Leaders’ emotions management plays a significant role to shape the followers’ behavioral outcomes, therefore, leaders try to regulate their emotions at the workplace with a view to influencing their followers’ behaviors. Moreover, emotional sincerity is a relatively new concept and this study took the first attempt to give insight understanding and clear picture about the role of leaders’ emotional sincerity in emotions management studies. The purpose of this study is to identify the new perspective of perceived emotional sincerity while discussing the role of leaders’ emotional labor strategies to shape the followers’ behaviors and this stream line of research is totally ignored in previous studies. This study examined the role of leaders’ emotional labor strategies (surface acting & deep acting) towards followers’ behaviors by concentrating on the moderating role of followers’ perceived emotional sincerity. The study is descriptive and quantitative in nature. Data have been collected by 200 dyads (Leader-Follower) from Malaysian NGOs by applying simple random sampling technique. Scales validation has been checked by confirmatory factor analysis (CFA) by using Smart PLS. Moreover, the structural equation modeling technique (SEM) has been used to test the hypotheses. Findings revealed that leaders’ surface acting is negatively and significantly related to followers’ behaviors (emotional engagement & positive emotional reactions). Moreover, results also enlightened that leaders’ deep acting has a positive and significant association with followers’ behaviors (emotional engagement & positive emotional reactions). Additionally, followers’ perceived emotional sincerity also significantly moderates on the relationship of leaders’ emotional labor strategies and followers’ behaviors. This study gives new direction for future studies to empirical test the ignored role of leaders’ emotional sincerity in emotions related studies.

Design of Mixed Flow Pump Impeller Blade using Mean Stream Line Theory and its Analysis

Given the importance of blade design in effective performance of the mixed flow pump, the present work demonstrates the designing of the mixed flow pump impeller blade using almost unexplored Mean stream line theory. The Mean stream line theory, though been used sparingly but has found to give comparable results to that of other templates of design. The design process has been carried out in AUTOCAD 2013 and Solid Works Premium 2014 software. The analysis for equivalent stress, equivalent elastic strain, Total deformation and the directional deformation have been carried out in ANSYS 2014 for different construction material of the blade i.e., stainless steel, titanium alloy, bronze, and copper alloy. Total deformation was found to be maximum for impeller blade made from titanium alloy whereas the equivalent stress and strain was least for titanium alloyed impeller blade. Further, a comparison analysis has been carried out for the equivalent stresses in blade designed using mean stream line theory and free vortex theory. It was observed that the equivalent stress in impeller blade designed using free vortex theory was lesser than that designed using mean stream line theory.

Nanofluid unsteady heat transfer in a porous energy storage enclosure in existence of Lorentz forces

In current article, nanofluid time dependent heat transfer under the influence of Lorentz forces during discharging process is simulated by means of FEM. In order to overcome the limitation of PCM, NEPCM has been utilized. CuO and water are employed as nanoparticles and PCM. Brownian motion role is taken into consideration to estimate nanofluid characteristics. Graphs are illustrated as isotherm, solid fraction and stream line contours. Results reveal that discharging rate improves with augment of Lorentz forces. As Hartmann number augments, solid fraction profile will be converged in lower time. Dispersing nanoparticles has significant impact on phase change front.

Fluid structure interaction finite element analysis of malformation of basilar artery fenestration

Objective Based on FSI finite element analysis, this study was designed to analyze the effects of hemodynamics on the malformation of basilar artery fenestration. Methods A total of 12 patients with malformation of basilar artery fenestration treated in Tianjin 4th Centre Hospital from 2009 to 2017 were studied retrospectively. With the patients’ CTA image data, the author built models and conducted FSI finite element analysis. By integratedly examining the WP, WSS and blood flow stream line, the author analyzed the average of WP and WSS, and selected six points calculating their WP and WSS: top of fenestration sub-bifurcation (P1), left medial walls of bifurcation proximal end (P2), right medial walls of bifurcation proximal end (P3), left lateral walls of bifurcation proximal end (P4), right lateral walls of bifurcation proximal end (P5), sub-junctions of fenestration (P6). Results Mean of WP was (1 472.03±950.09) Pa and the maximum WP was at P1 (2 510.61±975.69) Pa, P=0.000; Mean of WSS was (28.40±5.83) Pa, and WSS of P2 (88.92±31.09) Pa, P=0.000 and P3 (86.76±24.07) Pa, P=0.000 were higher; WSS of P4 (8.60±9.17) Pa, P=0.002, P5 (10.47±8.59) Pa, P=0.006 and P6 (4.94±1.29) Pa, P=0.000 were lower, and the blood flow stream line showed that low velocity turbulence appeared at P4, P5 and P6. Conclusion In the cases of malformation of basilar artery fenestration, high WP at P1 and high WSS at P2 and P3 were the key predisposing factors of aneurysm; while low velocity turbulence and low WSS at P4, P5 and P6 facilitated the formation of atherosclerosis plaque. Key words: Malformation of basilar artery fenestration; Aneurysms; Atherosclerosis plaque; Fluid solid interaction; Hemodynamics

THE THREE-DIMENSIONAL FLOW SIMULATION OF A FLAPPING WING

This study investigates three-dimensional (3D) flow fields around a flapping wing with a span of 20 cm. Numerical simulations are performed by varying the simulation mesh density for a half-flapping-wing profile with wind tunnel domain for flapping stroke angles of 53° and 90°. Wind velocities ranging from 1 to 3 m/s, variation in flapping frequency of 14-15 Hz, and corresponding lift characteristics are obtained. Comparative evaluation of numerical and experimental lift force data reveals the translational and rotational lift phenomena of Dickinson’s mechanisms. The stream line that flows over the 3D wing profile is found to be in good agreement with the existing smoke trace experimental data. The motions of a flapping wing obtained through 3D stereo photography and COMSOL Multiphysics simulation are compared and the aerodynamic characteristics are exploited. The streamwise and spanwise 3D velocity fields with intercepting planes at three chord sections are explored, and the reverse Karman vortex sheet is observed. The comparison of the simulation and experimental results for a 3D flapping wing provides insight into the motion characteristics of a flapping wing and flapping wing aerodynamic analysis of micro air vehicles.

Is there a role for computational fluid dynamics (CFD) in neurovascular compression syndrome?

Abstract Introduction - CFD uses complex algorithms to predict flow of fluids through a tube & also predicts its impact on walls. It is increasingly being used for prediction of aneurysmal wall thickness, flow, wall shear stress and to decide clip strategy. This is an experimental study, which analyses use of CFD in neurovascular compression syndrome and probable future applications. We analysed CFD findings in 12 cases retrospectively to know fluid dynamics of vessels and its implications. Methodology - Twelve patients - 7 cases of trigeminal neuralgia and 5 of hemifacial spasm who were to be treated by MVD, were enrolled. CFD i.e. WSSv (wall shear stress vector), WSSm (magnitude), SL (stream line) and Pressure, was done in all prospectively. Results - CFD of superior cerebellar artery, anterior inferior cerebellar artery and vertebral artery was done in each case at the contact site and immediate pre + post contact location. Comparitively High WSSm correlated maximally at nerve vessel contact junction (NVCj) and also high SL at the NVCj comparing with nerve vessel contact proximal (NVCp), WSSv showed wide variations and pressure change was in-conclusive. Conclusion - At contact site, the high WSSm& SL might be a reliable indicator of a neurovascular conflict zone. To conclusively validate the findings we need large number of patients and control group.

Hydrodynamic buffer effect on the fall-off core barrel assembly in hypothetical drop accident

Hypothetical accident analysis is of great importance for design and research of nuclear reactor. The core barrel assembly is assumed to fall off in a hypothetical drop accident and we conducted a numerical simulation to study the hydrodynamic buffer effect with CFD dynamic mesh. An orifice plate with square holes was designed to simplify the reactor core and two kinds of circumstances were compared in this investigation, including the normal operating condition (high-temperature dynamic water) and the still water situation (low-temperature). Distribution of flow field (e.g. pressure contour, velocity vector and stream line) at the moment of impact was analyzed. Due to the significant buffer effect of dynamic coolant flow, it has a greater hydrodynamic force and a smaller falling velocity respectively in normal operating condition than that in still water situation. The change laws of the hydrodynamic force and the falling velocity are similar in normal operating condition that they increase first and then decrease from their peak values (2410.2 kN and 0.16 m/s respectively). Whereas in still water situation, the hydrodynamic force rapidly increases to 835.5 kN (peak value) and maintains stable a level subsequently, meanwhile the falling velocity increases continuously with parabolic growth. The fall-off assembly is inferred to achieve effective hydrodynamic buffer in drop accident during normal operation. As well, the investigation also provides input parameters to subsequent research on impact load of the secondary support structure.

Design and optimization of mixed flow pump impeller blades by varying semi-cone angle

The mixed flow pump is a cross between the axial and radial flow pump. These pumps are used in a large number of applications in modern fields. For the designing of these mixed flow pump impeller blades, a lot number of design parameters are needed to be considered which makes this a tedious task for which fundamentals of turbo-machinery and fluid mechanics are always prerequisites. The semi-cone angle of mixed flow pump impeller blade has a specified range of variations generally between 45o to 60o. From the literature review done related to this topic researchers have considered only a particular semi-cone angle and all the calculations are based on this very same semi-cone angle. By varying this semi-cone angle in the specified range, it can be verified if that affects the designing of the impeller blades for a mixed flow pump. Although a lot of methods are available for designing of mixed flow pump impeller blades like inverse time marching method, the pseudo-stream function method, Fourier expansion singularity method, free vortex method, mean stream line theory method etc. still the optimized design of the mixed flow pump impeller blade has been a cumbersome work. As stated above since all the available research works suggest or propose the blade designs with constant semi-cone angle, here the authors have designed the impeller blades by varying the semi-cone angle in a particular range with regular intervals for a Mixed-Flow pump. Henceforth several relevant impeller blade designs are obtained and optimization is carried out to obtain the optimized design (blade with optimal geometry) of impeller blade.

Effect of perforation on exhaust performance of a turbo pipe type muffler using methanol and gasoline blended fuel: A step to NOx control

Abstract There is an extensive global effort to replace fossil fuel with blended fuel within existing engine configuration, yet conformed to available infrastructure. Though blended alcoholic fuel is able to reduce carbonated emissions (CO, CO2, unburnt HC), the NOx level increased significantly due to enhanced exhaust temperature resulted out of better combustion. At Green Engine Technology Center, new exhaust mufflers are fabricated with/without perforation to find out if new design of muffler develops less temperature. The main objective of this study is to investigate feasibility of using perforation in diminishing surface temperature. To achieve this, a computational fluid dynamics model is developed to study the effect of perforation on exhaust performance of a turbo pipe type straight and elliptic muffler, fitted to engine running on petrol-methanol blend. The CFD analysis is done through a pressure based solver to study the effect of perforation on back pressure, density, temperature. Prior to the result analysis, the model is validated with a fabricated chamber type prototype muffler fitted to a four stroke single cylinder petrol engine. The temperature thus measured is matching with the simulated temperature. The muffler performance parameters such as back pressure, temperature, density, velocity stream line are studied for different blends (5%, 10%, 15%) of petrol and methanol. Clear variations of these parameters are observed between non perforated and perforated type turbo pipe mufflers.

Evaluation of an emergency response service

AIMS AND METHOD An emergency response service (ERS) was introduced to streamline the assessment of individuals presenting in a crisis in one sector of a large provincial city. Data on service activity, clinical details and outcome were recorded on consecutive referrals to the service over the first 6 months of operation, and all patients were offered the opportunity to complete the Client Satisfaction Questionnaire. RESULTS Seventy-five per cent of those referred accepted the offer of assessment, and the majority were seen in their own home within 2 hours. One in ten individuals were not offered any further mental health input and 17% were hospitalised. The number of admissions via primary care fell by 60% after the introduction of this service. However, at its peak of activity the service received an average of only two referrals per day and three each weekend. Only 30% of referrals were received outside of normal office hours. Service users and general practitioners were found to be more satisfied with the service than the staff that provided it. CLINICAL IMPLICATIONS The introduction of the ERS led to a faster, more consistent process of assessment of crisis referrals and assessment undertakings in the community, and appeared to increase the use of alternative treatments for individuals in crisis before resorting to admission. Funding opportunities are restricted for the development of crisis services. The development of emergency response services for the use of current staff from a number of community mental health teams is an option worth considering.

Alberta Learning Factory for training reconfigurable assembly process value stream mapping

The University of Alberta is currently coping with the training and learning needs of the rapidly increasing number of manufacturing companies across Alberta. The current shift towards industry 4.0 further requires learning with reconfigurable systems. The Alberta learning Factory (AllFactory) is a step towards the creation of an experiential and project-based learning environment, where students are trained in cross-disciplinary project management. Various lean management tools, such as value stream management, line balancing, bottleneck identification, Kanban, shop-floor design, and visual tools are integrated into student group projects. The students are given the task to assemble a Lego-based 3D Printing machine (prototyped in the AllFactory) with different sub-assemblies in a factory simulation environment. The main idea of using Legos is to demonstrate re-configurability as required by industry 4.0. The research in AllFactory is based on Lean tools integrated to the process/product information data from the ERP system, which is connected to the factory shop-floor. Currently, two important research topics in AllFactory are: 1) a Hybrid Lean-ERP systems development; and 2) the development of a generalized value stream mapping system for construction companies. These research topics feed directly to the training modules in the learning factory. This new learning factory will focus initially on re-configurable manufacturing systems, which will be extended to transdisciplinary capstone projects and a training school for industry personnel in the future.

Using software such as “kuaishou” to shooting videos

In a small stream line under the big trend, this paper gives a brief introduction to using software such as “kuaishou” to shooting a small video. This research concerns several parts: introduction, the writing of the script, the selection of actor, props, post-production and innovation. A small video is been made of five steps, based on this, it is been detailed on each piece of analysis to better complete the video. The purpose of this study is to show the methods mentioned above are promising. In this Internet age, this kind of video with one of the biggest bright spots, that is its powerful ability to turn into cash. The developed technique is applied to shooting videos for making money.

Investigation of feasibility of wind turbulence measurement by a pulsed coherent doppler lidar in the atmospheric boundary layer

Feasibilities of determination of the wind turbulence parameters from data measured by the Stream Line coherent Doppler lidar under different atmospheric conditions have been studied experimentally. It has been found that the spatial structure of the turbulence is described well by the von Karman model in the layer of intensive mixing. From the lidar measurements at night under stable conditions the estimation of the outer scale of turbulence with the use of the von Karman model is not possible.

Design and Optimization of Mixed Flow Pump Impeller Blades with Hydrostatic Loading and Varying Semi-Cone Angle

Mixed Flow pumps are a combination of both axial and radial flow pumps. In present days they are having a wide range of applications. The impeller blade designing of mixed flow pump has always been a difficult task, the reason being it requires a lot of designing parameter to be considered for successful designing. When compared with radial and axial flow turbo-machines the mixed flow type of turbo-machines always get less importance for these complexities in their designing process. This complexity arises because of the complicated blade and geometry of fluid flow passage. Impeller is considered as one of the most important components in a mixed flow pump for the flow passage. The main motive behind the study of impeller blade design is to cite the reasons for the low hydraulic performance of the pump originally taken into consideration. When the pump is in functioning or operating condition, the rotation of the impeller provides with a geometric shape and the passage of flow gets distorted. It has been observed that all the available designs of the mixed flow pump, impeller blades are designed with a constant semi-cone angle, where as various data books for pump model test signify the fact that the semi-cone angle for these impeller blades can vary a specified range. So it is always an option to verify the fact that if variation of semi-cone angle in this specified range affects the designing parameters or not. From the literature survey it is found that various design methods such as Fourier expansion singularity method, free vortex method, mean stream line theory method, inverse time marching method, the pseudo-stream function method etc., adapted by various researchers, but the design methodology is always a tedious task.Here the authors have proposed the blade designs with a variation of semi-cone at hub.The concepts of Fluid Mechanics and Hydraulic Machines play a vital role in this designing process. Further taking the Hydraulic loading into consideration analysis is done to obtain the possible designs for the impeller blades. Finally optimization is carried out and the optimized design (blade with optimal geometry) is obtained with a varying semi-cone angle taking Hydraulic Loading into consideration.