Search results for: simulation parameters
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 12612

Search results for: simulation parameters

11082 Joint Path and Push Planning among Moveable Obstacles

Authors: Victor Emeli, Akansel Cosgun

Abstract:

This paper explores the navigation among movable obstacles (NAMO) problem and proposes joint path and push planning: which path to take and in what direction the obstacles should be pushed at, given a start and goal position. We present a planning algorithm for selecting a path and the obstacles to be pushed, where a rapidly-exploring random tree (RRT)-based heuristic is employed to calculate a minimal collision path. When it is necessary to apply a pushing force to slide an obstacle out of the way, the planners leverage means-end analysis through a dynamic physics simulation to determine the sequence of linear pushes to clear the necessary space. Simulation experiments show that our approach finds solutions in higher clutter percentages (up to 49%) compared to the straight-line push planner (37%) and RRT without pushing (18%).

Keywords: motion planning, path planning, push planning, robot navigation

Procedia PDF Downloads 161
11081 Environmental Conditions Simulation Device for Evaluating Fungal Growth on Wooden Surfaces

Authors: Riccardo Cacciotti, Jiri Frankl, Benjamin Wolf, Michael Machacek

Abstract:

Moisture fluctuations govern the occurrence of fungi-related problems in buildings, which may impose significant health risks for users and even lead to structural failures. Several numerical engineering models attempt to capture the complexity of mold growth on building materials. From real life observations, in cases with suppressed daily variations of boundary conditions, e.g. in crawlspaces, mold growth model predictions well correspond with the observed mold growth. On the other hand, in cases with substantial diurnal variations of boundary conditions, e.g. in the ventilated cavity of a cold flat roof, mold growth predicted by the models is significantly overestimated. This study, founded by the Grant Agency of the Czech Republic (GAČR 20-12941S), aims at gaining a better understanding of mold growth behavior on solid wood, under varying boundary conditions. In particular, the experimental investigation focuses on the response of mold to changing conditions in the boundary layer and its influence on heat and moisture transfer across the surface. The main results include the design and construction at the facilities of ITAM (Prague, Czech Republic) of an innovative device allowing for the simulation of changing environmental conditions in buildings. It consists of a square section closed circuit with rough dimensions 200 × 180 cm and cross section roughly 30 × 30 cm. The circuit is thermally insulated and equipped with an electric fan to control air flow inside the tunnel, a heat and humidity exchange unit to control the internal RH and variations in temperature. Several measuring points, including an anemometer, temperature and humidity sensor, a loading cell in the test section for recording mass changes, are provided to monitor the variations of parameters during the experiments. The research is ongoing and it is expected to provide the final results of the experimental investigation at the end of 2022.

Keywords: moisture, mold growth, testing, wood

Procedia PDF Downloads 125
11080 Effectiveness of Simulation Resuscitation Training to Improve Self-Efficacy of Physicians and Nurses at Aga Khan University Hospital in Advanced Cardiac Life Support Courses Quasi-Experimental Study Design

Authors: Salima R. Rajwani, Tazeen Ali, Rubina Barolia, Yasmin Parpio, Nasreen Alwani, Salima B. Virani

Abstract:

Introduction: Nurses and physicians have a critical role in initiating lifesaving interventions during cardiac arrest. It is important that timely delivery of high quality Cardio Pulmonary Resuscitation (CPR) with advanced resuscitation skills and management of cardiac arrhythmias is a key dimension of code during cardiac arrest. It will decrease the chances of patient survival if the healthcare professionals are unable to initiate CPR timely. Moreover, traditional training will not prepare physicians and nurses at a competent level and their knowledge level declines over a period of time. In this regard, simulation training has been proven to be effective in promoting resuscitation skills. Simulation teaching learning strategy improves knowledge level, and skills performance during resuscitation through experiential learning without compromising patient safety in real clinical situations. The purpose of the study is to evaluate the effectiveness of simulation training in Advanced Cardiac Life Support Courses by using the selfefficacy tool. Methods: The study design is a quantitative research design and non-randomized quasi-experimental study design. The study examined the effectiveness of simulation through self-efficacy in two instructional methods; one is Medium Fidelity Simulation (MFS) and second is Traditional Training Method (TTM). The sample size was 220. Data was compiled by using the SPSS tool. The standardized simulation based training increases self-efficacy, knowledge, and skills and improves the management of patients in actual resuscitation. Results: 153 students participated in study; CG: n = 77 and EG: n = 77. The comparison was done between arms in pre and post-test. (F value was 1.69, p value is <0.195 and df was 1). There was no significant difference between arms in the pre and post-test. The interaction between arms was observed and there was no significant difference in interaction between arms in the pre and post-test. (F value was 0.298, p value is <0.586 and df is 1. However, the results showed self-efficacy scores were significantly higher within experimental group in post-test in advanced cardiac life support resuscitation courses as compared to Traditional Training Method (TTM) and had overall (p <0.0001) and F value was 143.316 (mean score was 45.01 and SD was 9.29) verses pre-test result showed (mean score was 31.15 and SD was 12.76) as compared to TTM in post-test (mean score was 29.68 and SD was 14.12) verses pre-test result showed (mean score was 42.33 and SD was 11.39). Conclusion: The standardized simulation-based training was conducted in the safe learning environment in Advanced Cardiac Life Suport Courses and physicians and nurses benefited from self-confidence, early identification of life-threatening scenarios, early initiation of CPR, and provides high-quality CPR, timely administration of medication and defibrillation, appropriate airway management, rhythm analysis and interpretation, and Return of Spontaneous Circulation (ROSC), team dynamics, debriefing, and teaching and learning strategies that will improve the patient survival in actual resuscitation.

Keywords: advanced cardiac life support, cardio pulmonary resuscitation, return of spontaneous circulation, simulation

Procedia PDF Downloads 78
11079 A Multi-Modal Virtual Walkthrough of the Virtual Past and Present Based on Panoramic View, Crowd Simulation and Acoustic Heritage on Mobile Platform

Authors: Lim Chen Kim, Tan Kian Lam, Chan Yi Chee

Abstract:

This research presents a multi-modal simulation in the reconstruction of the past and the construction of present in digital cultural heritage on mobile platform. In bringing the present life, the virtual environment is generated through a presented scheme for rapid and efficient construction of 360° panoramic view. Then, acoustical heritage model and crowd model are presented and improvised into the 360° panoramic view. For the reconstruction of past life, the crowd is simulated and rendered in an old trading port. However, the keystone of this research is in a virtual walkthrough that shows the virtual present life in 2D and virtual past life in 3D, both in an environment of virtual heritage sites in George Town through mobile device. Firstly, the 2D crowd is modelled and simulated using OpenGL ES 1.1 on mobile platform. The 2D crowd is used to portray the present life in 360° panoramic view of a virtual heritage environment based on the extension of Newtonian Laws. Secondly, the 2D crowd is animated and rendered into 3D with improved variety and incorporated into the virtual past life using Unity3D Game Engine. The behaviours of the 3D models are then simulated based on the enhancement of the classical model of Boid algorithm. Finally, a demonstration system is developed and integrated with the models, techniques and algorithms of this research. The virtual walkthrough is demonstrated to a group of respondents and is evaluated through the user-centred evaluation by navigating around the demonstration system. The results of the evaluation based on the questionnaires have shown that the presented virtual walkthrough has been successfully deployed through a multi-modal simulation and such a virtual walkthrough would be particularly useful in a virtual tour and virtual museum applications.

Keywords: Boid Algorithm, Crowd Simulation, Mobile Platform, Newtonian Laws, Virtual Heritage

Procedia PDF Downloads 274
11078 Numerical Investigation of Fluid Outflow through a Retinal Hole after Scleral Buckling

Authors: T. Walczak, J. K. Grabski, P. Fritzkowski, M. Stopa

Abstract:

Objectives of the study are i) to perform numerical simulations that permit an analysis of the dynamics of subretinal fluid when an implant has induced scleral intussusception and ii) assess the impact of the physical parameters of the model on the flow rate. Computer simulations were created using finite element method (FEM) based on a model that takes into account the interaction of a viscous fluid (subretinal fluid) with a hyperelastic body (retina). The purpose of the calculation was to investigate the dependence of the flow rate of subretinal fluid through a hole in the retina on different factors such as viscosity of subretinal fluid, material parameters of the retina, and the offset of the implant from the retina’s hole. These simulations were performed for different speeds of eye movement that reflect the behavior of the eye when reading, REM, and saccadic movements. Similar to other works in the field of subretinal fluid flow, it was assumed stationary, single sided, forced fluid flow in the considered area simulating the subretinal space. Additionally, a hyperelastic material model of the retina and parameterized geometry of the considered model was adopted. The calculations also examined the influence the direction of the force of gravity due to the position of the patient’s head on the trend of outflow of fluid. The simulations revealed that fluid outflow from the retina becomes significant with eyeball movement speed of 100°/sec. This speed is greater than in the case of reading but is four times less than saccadic movement. The increase of viscosity of the fluid increased beneficial effect. Further, the simulation results suggest that moderate eye movement speed is optimal and that the conventional prescription of the avoidance of routine eye movement following retinal detachment surgery should be relaxed. Additionally, to verify numerical results, some calculations were repeated with use of meshless method (method of fundamental solutions), which is relatively fast and easy to implement. The paper has been supported by 02/21/DSPB/3477 grant.

Keywords: CFD simulations, FEM analysis, meshless method, retinal detachment

Procedia PDF Downloads 338
11077 Ozone Treatment in Textile Industry

Authors: Umut Çınar

Abstract:

The fact that ozone gas has color bleaching properties has made the use of ozone gas widespread in the textile sector as well as in many other sectors. Ozone gas, which is a strong oxidative agent on the fabric, causes the paint on the fabric to wear off and lighten its color with an aged appearance. Within the scope of this thesis, parameters affecting the bleaching properties of ozone gas on reactive dyed knitted fabric, which is rare in the literature, were investigated. Ozone concentration, time, and pH values were analyzed with the Box Behnken experimental design method, and optimum conditions were determined. After the experiments, wear and opacity values were measured with the help of a spectrophotometer. With the help of the Design Expert program, the graphics related to the data were prepared and interpreted with Box Behnken and ANOVA. These experiments on reactive dyed knitted fabric were tested on these parameters, and the spectrophotometric values of the fabric and optimum parameters in abrasion and opacity were revealed.

Keywords: ozone, reactive dye, bleaching, textile, garment wash, sustainability, washing, Box–Behnken, experimental design

Procedia PDF Downloads 64
11076 Electricity Demand Modeling and Forecasting in Singapore

Authors: Xian Li, Qing-Guo Wang, Jiangshuai Huang, Jidong Liu, Ming Yu, Tan Kok Poh

Abstract:

In power industry, accurate electricity demand forecasting for a certain leading time is important for system operation and control, etc. In this paper, we investigate the modeling and forecasting of Singapore’s electricity demand. Several standard models, such as HWT exponential smoothing model, the ARMA model and the ANNs model have been proposed based on historical demand data. We applied them to Singapore electricity market and proposed three refinements based on simulation to improve the modeling accuracy. Compared with existing models, our refined model can produce better forecasting accuracy. It is demonstrated in the simulation that by adding forecasting error into the forecasting equation, the modeling accuracy could be improved greatly.

Keywords: power industry, electricity demand, modeling, forecasting

Procedia PDF Downloads 636
11075 Performance Evaluation of Using Genetic Programming Based Surrogate Models for Approximating Simulation Complex Geochemical Transport Processes

Authors: Hamed K. Esfahani, Bithin Datta

Abstract:

Transport of reactive chemical contaminant species in groundwater aquifers is a complex and highly non-linear physical and geochemical process especially for real life scenarios. Simulating this transport process involves solving complex nonlinear equations and generally requires huge computational time for a given aquifer study area. Development of optimal remediation strategies in aquifers may require repeated solution of such complex numerical simulation models. To overcome this computational limitation and improve the computational feasibility of large number of repeated simulations, Genetic Programming based trained surrogate models are developed to approximately simulate such complex transport processes. Transport process of acid mine drainage, a hazardous pollutant is first simulated using a numerical simulated model: HYDROGEOCHEM 5.0 for a contaminated aquifer in a historic mine site. Simulation model solution results for an illustrative contaminated aquifer site is then approximated by training and testing a Genetic Programming (GP) based surrogate model. Performance evaluation of the ensemble GP models as surrogate models for the reactive species transport in groundwater demonstrates the feasibility of its use and the associated computational advantages. The results show the efficiency and feasibility of using ensemble GP surrogate models as approximate simulators of complex hydrogeologic and geochemical processes in a contaminated groundwater aquifer incorporating uncertainties in historic mine site.

Keywords: geochemical transport simulation, acid mine drainage, surrogate models, ensemble genetic programming, contaminated aquifers, mine sites

Procedia PDF Downloads 274
11074 Investigation of Some Sperm Quality Parameters of Farmed and Wild-Caught Meagre (Argyrosomus regius Asso, 1801)

Authors: Şefik Surhan Tabakoğlu, Hipolito Fernández-Palacios, Dominique Schuchardt, Mahmut Ali Gökçe, Celal Erbaş, Oğuz Taşbozan

Abstract:

This study aimed to clarify some sperm quality parameters such as volumetric sperm quantity, motility, motility duration, sperm density, total number of spermatozoa and pH of meagre (Argyrosomus regius ASSO, 1801) individuals kept in farming conditions and caught from wild (las palmas, gran canary). The sperm was collected in glass tubes graded in millimetres and sperm volume registered immediately following collection by abdominal massage. The sperm quality parameters including motility, total number of spermatozoa and spermatozoa density were determined with computer assisted sperm analysis (CASA) program. The duration of spermatozoa movement was assessed using a sensitive chronometer (1/100s) that was started simultaneously with the addition of activation solution into the sample. Sperm pH was measured with standard pH electrodes within five minutes of sampling. At the end of the study, while amount of sperm (5.20±0.33 ml), duration of motility (7.23±0.7 m) and total number of spermatozoa (131.40±12.22 x10^9) were different statistically (p < 0,05), motility (% 81.03±6.59), pH (7.30±0.08), sperm density (25.27±9.42 x10^9/ml) and morphologic parameters were not significantly different between the two groups. According to our results, amount of sperm, duration of motility and total number of spermatozoa were better in farmed group than that of the other group.

Keywords: Seriola rivoliana, meagre, sperm quality, motility, motility duration

Procedia PDF Downloads 370
11073 Simulation Modelling of the Transmission of Concentrated Solar Radiation through Optical Fibres to Thermal Application

Authors: M. Rahou, A. J. Andrews, G. Rosengarten

Abstract:

One of the main challenges in high-temperature solar thermal applications transfer concentrated solar radiation to the load with minimum energy loss and maximum overall efficiency. The use of a solar concentrator in conjunction with bundled optical fibres has potential advantages in terms of transmission energy efficiency, technical feasibility and cost-effectiveness compared to a conventional heat transfer system employing heat exchangers and a heat transfer fluid. In this paper, a theoretical and computer simulation method is described to estimate the net solar radiation transmission from a solar concentrator into and through optical fibres to a thermal application at the end of the fibres over distances of up to 100 m. A key input to the simulation is the angular distribution of radiation intensity at each point across the aperture plane of the optical fibre. This distribution depends on the optical properties of the solar concentrator, in this case, a parabolic mirror with a small secondary mirror with a common focal point and a point-focus Fresnel lens to give a collimated beam that pass into the optical fibre bundle. Since solar radiation comprises a broad band of wavelengths with very limited spatial coherence over the full range of spectrum only ray tracing models absorption within the fibre and reflections at the interface between core and cladding is employed, assuming no interference between rays. The intensity of the radiation across the exit plane of the fibre is found by integrating across all directions and wavelengths. Results of applying the simulation model to a parabolic concentrator and point-focus Fresnel lens with typical optical fibre bundle will be reported, to show how the energy transmission varies with the length of fibre.

Keywords: concentrated radiation, fibre bundle, parabolic dish, fresnel lens, transmission

Procedia PDF Downloads 559
11072 Reduction of Rotor-Bearing-Support Finite Element Model through Substructuring

Authors: Abdur Rosyid, Mohamed El-Madany, Mohanad Alata

Abstract:

Due to simplicity and low cost, rotordynamic system is often modeled by using lumped parameters. Recently, finite elements have been used to model rotordynamic system as it offers higher accuracy. However, it involves high degrees of freedom. In some applications such as control design, this requires higher cost. For this reason, various model reduction methods have been proposed. This work demonstrates the quality of model reduction of rotor-bearing-support system through substructuring. The quality of the model reduction is evaluated by comparing some first natural frequencies, modal damping ratio, critical speeds and response of both the full system and the reduced system. The simulation shows that the substructuring is proven adequate to reduce finite element rotor model in the frequency range of interest as long as the numbers and the locations of master nodes are determined appropriately. However, the reduction is less accurate in an unstable or nearly-unstable system.

Keywords: rotordynamic, finite element model, timoshenko beam, 3D solid elements, Guyan reduction method

Procedia PDF Downloads 269
11071 Investigation of Failure Mechanisms of Composite Laminates with Delamination and Repaired with Bolts

Authors: Shuxin Li, Peihao Song, Haixiao Hu, Dongfeng Cao

Abstract:

The interactive deformation and failure mechanisms, including local bucking/delamination propagation and global bucking, are investigated in this paper with numerical simulation and validation with experimental results. Three dimensional numerical models using ABAQUS brick elements combined with cohesive elements and contact elements are developed to simulate the deformation and failure characteristics of composite laminates with and without delamination under compressive loading. The zero-thickness cohesive elements are inserted on the possible path of delamination propagation, and the inter-laminate behavior is characterized by the mixed-mode traction-separation law. The numerical simulations identified the complex feature of interaction among local buckling and/or delamination propagation and final global bucking for composite laminates with delamination under compressive loading. Firstly there is an interaction between the local buckling and delamination propagation, i.e., local buckling induces delamination propagation, and then delamination growth further enhances the local buckling. Secondly, the interaction between the out-plan deformation caused by local buckling and the global bucking deformation results in final failure of the composite laminates. The simulation results are validated by the good agreement with the experimental results published in the literature. The numerical simulation validated with experimental results revealed that the degradation of the load capacity, in particular of the compressive strength of composite structures with delamination, is mainly attributed to the combined local buckling/delamination propagation effects. Consequently, a simple field-bolt repair approach that can hinder the local buckling and prevent delamination growth is explored. The analysis and simulation results demonstrated field-bolt repair could effectively restore compressive strength of composite laminates with delamination.

Keywords: cohesive elements, composite laminates, delamination, local and global bucking, field-bolt repair

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11070 Storage Influence on Physico-Chemical Composition and Antioxidant Activity of Jamun Drink Prepared From Two Types of Pulp

Authors: Muhammad Atif Randhawa, Mahreen Akhtar, Sidrah

Abstract:

In this paper, Jamun (Syzygium cumini; Myrtaceae) drink enriched with jamun pulp and seed was assessed for different physicochemical parameters (titratable acidity, pH, TSS, ascorbic acid, and total sugars and reducing sugars) and phytochemical aspects at every 15 days interval till 60 days storage period. Jamun pulp both with seed and without seed were used at levels of 7, 10 and 13 percent to prepare jamun drink in six combinations; T1 (7% pulp without seed), T2 (10% pulp without seed), T3 (13% pulp without seed), T4 (7% pulp with seed), T5 (10% pulp with seed), T6 (13% pulp with seed). Storage period resulted decrease in pH (4.18 to 4.08) and ascorbic acid (21.92%) significantly along with phenolic contents (6.13 to 4.85g of GAE/kg) and antioxidant activity (70.68 to 48.62 percent) within treatments. All treatments showed significant increases in total sugars (11.59 to 11.80%), reducing sugars (2.30 to 2.50%), TSS (12.2 to 13.32 °B) and acidity (0.23% to 0.31%) during storage. Treatments T3, T5 and T6 showed best results in terms of all physicochemical parameters during storage. Statistically significant differences were obtained among sensory parameters as a function of pulp type and concentration, while treatment T5 (10% pulp with seed) obtained highest score (7.16) in terms of all sensory parameters. It can be concluded that nutrient rich jamun drink can be prepared as an attempt to add value to the underutilized jamun fruit of Pakistan.

Keywords: antioxidant activity, Jamun beverage, physicochemical, storage

Procedia PDF Downloads 307
11069 Synthesis of TiO2 Nanoparticles by Sol-Gel and Sonochemical Combination

Authors: Sabriye Piskin, Sibel Kasap, Muge Sari Yilmaz

Abstract:

Nanocrystalline TiO2 particles were successfully synthesized via sol-gel and sonochemical combination using titanium tetraisopropoxide as a precursor at lower temperature for a short time. The effect of the reaction parameters (hydrolysis media, acid media, and reaction temperatures) on the synthesis of TiO2 particles were investigated in the present study. Characterizations of synthesized samples were prepared by X-ray diffraction (XRD) analysis. It was shown that the reaction parameters played a significant role in the synthesis of TiO2 particles.

Keywords: crystalline TiO2, sonochemical mechanism, sol-gel reaction, XRD

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11068 Parameter Estimation with Uncertainty and Sensitivity Analysis for the SARS Outbreak in Hong Kong

Authors: Afia Naheed, Manmohan Singh, David Lucy

Abstract:

This work is based on a mathematical as well as statistical study of an SEIJTR deterministic model for the interpretation of transmission of severe acute respiratory syndrome (SARS). Based on the SARS epidemic in 2003, the parameters are estimated using Runge-Kutta (Dormand-Prince pairs) and least squares methods. Possible graphical and numerical techniques are used to validate the estimates. Then effect of the model parameters on the dynamics of the disease is examined using sensitivity and uncertainty analysis. Sensitivity and uncertainty analytical techniques are used in order to analyze the affect of the uncertainty in the obtained parameter estimates and to determine which parameters have the largest impact on controlling the disease dynamics.

Keywords: infectious disease, severe acute respiratory syndrome (SARS), parameter estimation, sensitivity analysis, uncertainty analysis, Runge-Kutta methods, Levenberg-Marquardt method

Procedia PDF Downloads 355
11067 Analysis of Heat Exchanger Area of Two Stage Cascade Refrigeration System Using Taguchi

Authors: A. D. Parekh

Abstract:

The present work describes relative contributions of operating parameters on required heat transfer area of three heat exchangers viz. evaporator, condenser and cascade condenser of two stage R404A-R508B cascade refrigeration system using Taguchi method. The operating parameters considered in present study includes (1) condensing temperature of high temperature cycle and low temperature cycle (2) evaporating temperature of low temperature cycle (3) degree of superheating in low temperature cycle (4) refrigerating effect. Heat transfer areas of three heat exchangers are studied with variation of above operating parameters and also optimum working levels of each operating parameter has been obtained for minimum heat transfer area of each heat exchanger using Taguchi method. The analysis using Taguchi method reveals that evaporating temperature of low temperature cycle and refrigerating effect contribute relatively largely on the area of evaporator. Condenser area is mainly influenced by both condensing temperature of high temperature cycle and refrigerating effect. Area of cascade condenser is mainly affected by refrigerating effect and the effects of other operating parameters are minimal.

Keywords: cascade refrigeration system, Taguchi method, heat transfer area, ANOVA, optimal solution

Procedia PDF Downloads 331
11066 Kinetic Monte Carlo Simulation of ZnSe Homoepitaxial Growth and Characterization

Authors: Hamid Khachab, Yamani Abdelkafi, Mouna Barhmi

Abstract:

The epitaxial growth has great important in the fabricate of the new semi-conductors devices and upgrading many factors, such as the quality of crystallization and efficiency with their deferent types and the most effective epitaxial technique is the molecular beam epitaxial. The MBE growth modeling allows to confirm the experiments results out by atomic beam and to analyze the microscopic phenomena. In of our work, we determined the growth processes specially the ZnSe epitaxial technique by Kinetic Monte Carlo method and we also give observations that are made in real time at the growth temperature using reflection high energy electron diffraction (RHEED) and photoemission current.

Keywords: molecular beam epitaxy, II-VI, morpholy, photoemission, RHEED, simulation, kinetic Monte Carlo, ZnSe

Procedia PDF Downloads 485
11065 Investigation of Bubble Growth During Nucleate Boiling Using CFD

Authors: K. Jagannath, Akhilesh Kotian, S. S. Sharma, Achutha Kini U., P. R. Prabhu

Abstract:

Boiling process is characterized by the rapid formation of vapour bubbles at the solid–liquid interface (nucleate boiling) with pre-existing vapour or gas pockets. Computational fluid dynamics (CFD) is an important tool to study bubble dynamics. In the present study, CFD simulation has been carried out to determine the bubble detachment diameter and its terminal velocity. Volume of fluid method is used to model the bubble and the surrounding by solving single set of momentum equations and tracking the volume fraction of each of the fluids throughout the domain. In the simulation, bubble is generated by allowing water-vapour to enter a cylinder filled with liquid water through an inlet at the bottom. After the bubble is fully formed, the bubble detaches from the surface and rises up during which the bubble accelerates due to the net balance between buoyancy force and viscous drag. Finally when these forces exactly balance each other, it attains a constant terminal velocity. The bubble detachment diameter and the terminal velocity of the bubble are captured by the monitor function provided in FLUENT. The detachment diameter and the terminal velocity obtained is compared with the established results based on the shape of the bubble. A good agreement is obtained between the results obtained from simulation and the equations in comparison with the established results.

Keywords: bubble growth, computational fluid dynamics, detachment diameter, terminal velocity

Procedia PDF Downloads 381
11064 Analysis of Heat Exchanger Area of Two Stage Cascade Refrigeration System Using Taguchi Methodology

Authors: A. D. Parekh

Abstract:

The present work describes relative contributions of operating parameters on required heat transfer area of three heat exchangers viz. evaporator, condenser and cascade condenser of two stage R404A-R508B cascade refrigeration system using Taguchi method. The operating parameters considered in present study includes (1) condensing temperature of high temperature cycle and low temperature cycle (2) evaporating temperature of low temperature cycle (3) degree of superheating in low temperature cycle (4) refrigerating effect. Heat transfer areas of three heat exchangers are studied with variation of above operating parameters and also optimum working levels of each operating parameter has been obtained for minimum heat transfer area of each heat exchanger using Taguchi method. The analysis using Taguchi method reveals that evaporating temperature of low temperature cycle and refrigerating effect contribute relatively largely on the area of evaporator. Condenser area is mainly influenced by both condensing temperature of high temperature cycle and refrigerating effect. Area of cascade condenser is mainly affected by refrigerating effect and the effects of other operating parameters are minimal.

Keywords: cascade refrigeration system, Taguchi method, heat transfer area, ANOVA, optimal solution

Procedia PDF Downloads 378
11063 Simulating an Interprofessional Hospital Day Shift: A Student Interprofessional (IP) Collaborative Learning Activity

Authors: Fiona Jensen, Barb Goodwin, Nancy Kleiman, Rhonda Usunier

Abstract:

Background: Clinical simulation is now a common component in many health profession curricula in preparation for clinical practice. In the Rady Faculty of Health Sciences (RFHS) college leads in simulation and interprofessional (IP) education, planned an eight hour simulated hospital day shift, where seventy students from six health professions across two campuses, learned with each other in a safe, realistic environment. Learning about interprofessional collaboration, an expected competency for many health professions upon graduation, was a primary focus of the simulation event. Method: Faculty representatives from the Colleges of Nursing, Medicine, Pharmacy and Rehabilitation Sciences (Physical Therapy, Occupation Therapy, Respiratory Therapy) and Pharmacy worked together to plan the IP event in a simulation facility in the College of Nursing. Each college provided a faculty mentor to guide the same profession students. Students were placed in interprofessional teams consisting of a nurse, physician, pharmacist, and then sharing respiratory, occupational, and physical therapists across the team depending on the needs of the patients. Eight patient scenarios were role played by health profession students, who had been provided with their patient’s story shortly before the event. Each team was guided by a facilitator. Results and Outcomes: On the morning of the event, all students gathered in a large group to meet mentors and facilitators and have a brief overview of the six competencies for effective collaboration and the session objectives. The students assuming their same profession roles were provided with their patient’s chart at the beginning of the shift, met with their team, and then completed professional specific assessments. Shortly into the shift, IP team rounds began, facilitated by the team facilitator. During the shift, each patient role-played a spontaneous health incident, which required collaboration between the IP team members for assessment and management. The afternoon concluded with team rounds, a collaborative management plan, and a facilitated de-brief. Conclusions: During the de-brief sessions, students responded to set questions related to the session learning objectives and expressed many positive learning moments. We believe that we have a sustainable simulation IP collaborative learning opportunity, which can be embedded into curricula, and has the capacity to grow to include more health profession faculties and students. Opportunities are being explored in the RFHS at the administrative level, to offer this event more frequently in the academic year to reach more students. In addition, a formally structured event evaluation tool would provide important feedback and inform the qualitative feedback to event organizers and the colleges about the significance of the simulation event to student learning.

Keywords: simulation, collaboration, teams, interprofessional

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11062 Numerical Simulation of Three-Dimensional Cavitating Turbulent Flow in Francis Turbines with ANSYS

Authors: Raza Abdulla Saeed

Abstract:

In this study, the three-dimensional cavitating turbulent flow in a complete Francis turbine is simulated using mixture model for cavity/liquid two-phase flows. Numerical analysis is carried out using ANSYS CFX software release 12, and standard k-ε turbulence model is adopted for this analysis. The computational fluid domain consist of spiral casing, stay vanes, guide vanes, runner and draft tube. The computational domain is discretized with a three-dimensional mesh system of unstructured tetrahedron mesh. The finite volume method (FVM) is used to solve the governing equations of the mixture model. Results of cavitation on the runner’s blades under three different boundary conditions are presented and discussed. From the numerical results it has been found that the numerical method was successfully applied to simulate the cavitating two-phase turbulent flow through a Francis turbine, and also cavitation is clearly predicted in the form of water vapor formation inside the turbine. By comparison the numerical prediction results with a real runner; it’s shown that the region of higher volume fraction obtained by simulation is consistent with the region of runner cavitation damage.

Keywords: computational fluid dynamics, hydraulic francis turbine, numerical simulation, two-phase mixture cavitation model

Procedia PDF Downloads 557
11061 Analysis of Operating Speed on Four-Lane Divided Highways under Mixed Traffic Conditions

Authors: Chaitanya Varma, Arpan Mehar

Abstract:

The present study demonstrates the procedure to analyse speed data collected on various four-lane divided sections in India. Field data for the study was collected at different straight and curved sections on rural highways with the help of radar speed gun and video camera. The data collected at the sections were analysed and parameters pertain to speed distributions were estimated. The different statistical distribution was analysed on vehicle type speed data and for mixed traffic speed data. It was found that vehicle type speed data was either follows the normal distribution or Log-normal distribution, whereas the mixed traffic speed data follows more than one type of statistical distribution. The most common fit observed on mixed traffic speed data were Beta distribution and Weibull distribution. The separate operating speed model based on traffic and roadway geometric parameters were proposed in the present study. The operating speed model with traffic parameters and curve geometry parameters were established. Two different operating speed models were proposed with variables 1/R and Ln(R) and were found to be realistic with a different range of curve radius. The models developed in the present study are simple and realistic and can be used for forecasting operating speed on four-lane highways.

Keywords: highway, mixed traffic flow, modeling, operating speed

Procedia PDF Downloads 459
11060 Comparison of Numerical and Laboratory Results of Pull-Out Test on Soil–Geogrid Interactions

Authors: Parisa Ahmadi Oliaei, Seyed Abolhassan Naeini

Abstract:

The knowledge of soil–reinforcement interaction parameters is particularly important in the design of reinforced soil structures. The pull-out test is one of the most widely used tests in this regard. The results of tensile tests may be very sensitive to boundary conditions, and more research is needed for a better understanding of the Pull-out response of reinforcement, so numerical analysis using the finite element method can be a useful tool for the understanding of the Pull-out response of soil-geogrid interaction. The main objective of the present study is to compare the numerical and experimental results of Pull- out a test on geogrid-reinforced sandy soils interactions. Plaxis 2D finite element software is used for simulation. In the present study, the pull-out test modeling has been done on sandy soil. The effect of geogrid hardness was also investigated by considering two different types of geogrids. The numerical results curve had a good agreement with the pull-out laboratory results.

Keywords: plaxis, pull-out test, sand, soil- geogrid interaction

Procedia PDF Downloads 162
11059 Development of Power System Stability by Reactive Power Planning in Wind Power Plant With Doubley Fed Induction Generators Generator

Authors: Mohammad Hossein Mohammadi Sanjani, Ashknaz Oraee, Oriol Gomis Bellmunt, Vinicius Albernaz Lacerda Freitas

Abstract:

The use of distributed and renewable sources in power systems has grown significantly, recently. One the most popular sources are wind farms which have grown massively. However, ¬wind farms are connected to the grid, this can cause problems such as reduced voltage stability, frequency fluctuations and reduced dynamic stability. Variable speed generators (asynchronous) are used due to the uncontrollability of wind speed specially Doubley Fed Induction Generators (DFIG). The most important disadvantage of DFIGs is its sensitivity to voltage drop. In the case of faults, a large volume of reactive power is induced therefore, use of FACTS devices such as SVC and STATCOM are suitable for improving system output performance. They increase the capacity of lines and also passes network fault conditions. In this paper, in addition to modeling the reactive power control system in a DFIG with converter, FACTS devices have been used in a DFIG wind turbine to improve the stability of the power system containing two synchronous sources. In the following paper, recent optimal control systems have been designed to minimize fluctuations caused by system disturbances, for FACTS devices employed. For this purpose, a suitable method for the selection of nine parameters for MPSH-phase-post-phase compensators of reactive power compensators is proposed. The design algorithm is formulated ¬¬as an optimization problem searching for optimal parameters in the controller. Simulation results show that the proposed controller Improves the stability of the network and the fluctuations are at desired speed.

Keywords: renewable energy sources, optimization wind power plant, stability, reactive power compensator, double-feed induction generator, optimal control, genetic algorithm

Procedia PDF Downloads 89
11058 Efficient Prediction of Surface Roughness Using Box Behnken Design

Authors: Ajay Kumar Sarathe, Abhinay Kumar

Abstract:

Production of quality products required for specific engineering applications is an important issue. The roughness of the surface plays an important role in the quality of the product by using appropriate machining parameters to eliminate wastage due to over machining. To increase the quality of the surface, the optimum machining parameter setting is crucial during the machining operation. The effect of key machining parameters- spindle speed, feed rate, and depth of cut on surface roughness has been evaluated. Experimental work was carried out using High Speed Steel tool and AlSI 1018 as workpiece material. In this study, the predictive model has been developed using Box-Behnken Design. An experimental investigation has been carried out for this work using BBD for three factors and observed that the predictive model of Ra value is closed to predictive value with a marginal error of 2.8648 %. Developed model establishes a correlation between selected key machining parameters that influence the surface roughness in a AISI 1018. F

Keywords: ANOVA, BBD, optimisation, response surface methodology

Procedia PDF Downloads 153
11057 Modeling and Calculation of Physical Parameters of the Pollution of Water by Oil and Materials in Suspensions

Authors: Ainas Belkacem, Fourar Ali

Abstract:

The present study focuses on the mathematical modeling and calculation of physical parameters of water pollution by oil and sand in regime fully dispersed in water. In this study, the sand particles and oil are suspended in the case of fully developed turbulence. The study consists to understand, model and predict the viscosity, the structure and dynamics of these types of mixtures. The work carried out is Numerical and validated by experience.

Keywords: multi phase flow, pollution, suspensions, turbulence

Procedia PDF Downloads 232
11056 Study on Discontinuity Properties of Phased-Array Ultrasound Transducer Affecting to Sound Pressure Fields Pattern

Authors: Tran Trong Thang, Nguyen Phan Kien, Trinh Quang Duc

Abstract:

The phased-array ultrasound transducer types are utilities for medical ultrasonography as well as optical imaging. However, their discontinuity characteristic limits the applications due to the artifacts contaminated into the reconstructed images. Because of the effects of the ultrasound pressure field pattern to the echo ultrasonic waves as well as the optical modulated signal, the side lobes of the focused ultrasound beam induced by discontinuity of the phased-array ultrasound transducer might the reason of the artifacts. In this paper, a simple method in approach of numerical simulation was used to investigate the limitation of discontinuity of the elements in phased-array ultrasound transducer and their effects to the ultrasound pressure field. Take into account the change of ultrasound pressure field patterns in the conditions of variation of the pitches between elements of the phased-array ultrasound transducer, the appropriated parameters for phased-array ultrasound transducer design were asserted quantitatively.

Keywords: phased-array ultrasound transducer, sound pressure pattern, discontinuous sound field, numerical visualization

Procedia PDF Downloads 500
11055 Effect of Incremental Forming Parameters on Titanium Alloys Properties

Authors: P. Homola, L. Novakova, V. Kafka, M. P. Oscoz

Abstract:

Shear spinning is closely related to the asymmetric incremental sheet forming (AISF) that could significantly reduce costs incurred by the fabrication of complex aeronautical components with a minimal environmental impact. The spinning experiments were carried out on commercially pure titanium (Ti-Gr2) and Ti-6Al-4V (Ti-Gr5) alloy. Three forming modes were used to characterize the titanium alloys properties from the point of view of different spinning parameters. The structure and properties of the materials were assessed by means of metallographic analyses and micro-hardness measurements. The highest value wall angle failure limit was achieved using spinning parameters mode for both materials. The feed rate effect was observed only in the samples from the Ti-Gr2 material, when a refinement of the grain microstructure with lower feed rate and higher tangential speed occurred. Ti-Gr5 alloy exhibited a decrease of the micro-hardness at higher straining due to recovery processes.

Keywords: incremental forming, metallography, shear spinning, titanium alloys

Procedia PDF Downloads 233
11054 A General Form of Characteristics Method Applied on Minimum Length Nozzles Design

Authors: Merouane Salhi, Mohamed Roudane, Abdelkader Kirad

Abstract:

In this work, we present a new form of characteristics method, which is a technique for solving partial differential equations. Typically, it applies to first-order equations; the aim of this method is to reduce a partial differential equation to a family of ordinary differential equations along which the solution can be integrated from some initial data. This latter developed under the real gas theory, because when the thermal and the caloric imperfections of a gas increases, the specific heat and their ratio do not remain constant anymore and start to vary with the gas parameters. The gas doesn’t stay perfect. Its state equation change and it becomes for a real gas. The presented equations of the characteristics remain valid whatever area or field of study. Here we need have inserted the developed Prandtl Meyer function in the mathematical system to find a new model when the effect of stagnation pressure is taken into account. In this case, the effects of molecular size and intermolecular attraction forces intervene to correct the state equation, the thermodynamic parameters and the value of Prandtl Meyer function. However, with the assumptions that Berthelot’s state equation accounts for molecular size and intermolecular force effects, expressions are developed for analyzing the supersonic flow for thermally and calorically imperfect gas. The supersonic parameters depend directly on the stagnation parameters of the combustion chamber. The resolution has been made by the finite differences method using the corrector predictor algorithm. As results, the developed mathematical model used to design 2D minimum length nozzles under effect of the stagnation parameters of fluid flow. A comparison for air with the perfect gas PG and high temperature models on the one hand and our results by the real gas theory on the other of nozzles shapes and characteristics are made.

Keywords: numerical methods, nozzles design, real gas, stagnation parameters, supersonic expansion, the characteristics method

Procedia PDF Downloads 239
11053 Investigation of Slope Stability in Gravel Soils in Unsaturated State

Authors: Seyyed Abolhasan Naeini, Ehsan Azini

Abstract:

In this paper, we consider the stability of a slope of 10 meters in silty gravel soils with modeling in the Geostudio Software.  we intend to use the parameters of the volumetric water content and suction dependent permeability and provides relationships and graphs using the parameters obtained from gradation tests and Atterberg’s limits. Also, different conditions of the soil will be investigated, including: checking the factor of safety and deformation rates and pore water pressure in drained, non-drained and unsaturated conditions, as well as the effect of reducing the water level on other parameters. For this purpose, it is assumed that the groundwater level is at a depth of 2 meters from the ground.  Then, with decreasing water level, the safety factor of slope stability was investigated and it was observed that with decreasing water level, the safety factor increased.

Keywords: slope stability analysis, factor of safety, matric suction, unsaturated silty gravel soil

Procedia PDF Downloads 172