Search results for: finite difference method (FDM)
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 23415

Search results for: finite difference method (FDM)

20895 The Use of Fractional Brownian Motion in the Generation of Bed Topography for Bodies of Water Coupled with the Lattice Boltzmann Method

Authors: Elysia Barker, Jian Guo Zhou, Ling Qian, Steve Decent

Abstract:

A method of modelling topography used in the simulation of riverbeds is proposed in this paper, which removes the need for datapoints and measurements of physical terrain. While complex scans of the contours of a surface can be achieved with other methods, this requires specialised tools, which the proposed method overcomes by using fractional Brownian motion (FBM) as a basis to estimate the real surface within a 15% margin of error while attempting to optimise algorithmic efficiency. This removes the need for complex, expensive equipment and reduces resources spent modelling bed topography. This method also accounts for the change in topography over time due to erosion, sediment transport, and other external factors which could affect the topography of the ground by updating its parameters and generating a new bed. The lattice Boltzmann method (LBM) is used to simulate both stationary and steady flow cases in a side-by-side comparison over the generated bed topography using the proposed method and a test case taken from an external source. The method, if successful, will be incorporated into the current LBM program used in the testing phase, which will allow an automatic generation of topography for the given situation in future research, removing the need for bed data to be specified.

Keywords: bed topography, FBM, LBM, shallow water, simulations

Procedia PDF Downloads 99
20894 Kernel Parallelization Equation for Identifying Structures under Unknown and Periodic Loads

Authors: Seyed Sadegh Naseralavi

Abstract:

This paper presents a Kernel parallelization equation for damage identification in structures under unknown periodic excitations. Herein, the dynamic differential equation of the motion of structure is viewed as a mapping from displacements to external forces. Utilizing this viewpoint, a new method for damage detection in structures under periodic loads is presented. The developed method requires only two periods of load. The method detects the damages without finding the input loads. The method is based on the fact that structural displacements under free and forced vibrations are associated with two parallel subspaces in the displacement space. Considering the concept, kernel parallelization equation (KPE) is derived for damage detection under unknown periodic loads. The method is verified for a case study under periodic loads.

Keywords: Kernel, unknown periodic load, damage detection, Kernel parallelization equation

Procedia PDF Downloads 288
20893 Determination of Iron, Zinc, Copper, Cadmium and Lead in Different Cigarette Brands in Yemen by Atomic Absorption Spectrometry

Authors: Ali A. Mutair

Abstract:

The concentration levels of iron (Fe), copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb) in different cigarette brands commonly produced and sold in Yemen were determined. Convenient sample treatment for cigarette tobacco of freshly opened packs was achieved by a sample preparation method based on dry digestion, and the concentrations of the analysed metals were measured by Flame Atomic Absorption Spectrometry (FAAS). The mean values obtained for Fe, Zn, Cu, Cd, and Pb in different Yemeni cigarette tobacco were 311, 52.2, 10.11, 1.71 and 4.06 µg/g dry weight, respectively. There is no more significant difference among cigarette brands tested. It was found that Fe was at the highest concentration, followed by Zn, Cu, Pb and Cd. The average relative standard deviation (RSD) ranged from 1.77% to 19.34%. The accuracy and precision of the results were checked by blank and recovery tests. The results show that Yemeni cigarettes contain heavy metal concentration levels that are similar to those in foreign cigarette brands reported by other studies in the worldwide.

Keywords: iron, zinc, copper, lead, cadmium, tobacco, Yemeni cigarette brands, atomic absorption spectrometry

Procedia PDF Downloads 360
20892 Effects of Bedside Rehabilitation of Stroke Patients in Activities and Daily Living Function

Authors: Chiung-Hua Chan, Fang-Yuan Chang, Li-Chi Huang

Abstract:

Stroke patients received regular rehabilitation therapy have measurable advancement in muscle strength, balance, control upper and lower physical activity, walking speed and endurance. This study aimed to investigate the relationship between increases in bedside rehabilitation time and the function of activities and daily living (ADL) in stroke patients. The study was quasi-experimental research design and randomized sampling. The researcher collected 12 stroke patients of stroke patients transferred to rehabilitation ward unit of a medical center during 1 January to 31 March 2017. All participants then were assigned to case group and control group. Data collection was through direct observation of assessment ADL of stroke patients by researchers on Day 1. Case group received regular rehabilitation, exercises in increase of bedside rehabilitation schedules exercise programs by ward nurses. Bedside rehabilitation exercise content with physical, functional and linguistic frequency and time, Control group only give routine rehabilitation schedule care. This was a randomized study performed in 12 patients who were stroke patients and transferred to rehabilitation ward unit of a medical center during 1 January to 31 March 2017. First, the researcher explained the purpose and method of the study to the patients or the family members. All participants completed a consent informed before participation. Patients were randomly assigned to a ‘bedside rehabilitation program’ (BRP) group and a control (C) group. The BRP group received bedside rehabilitation schedules exercise programs by ward nurses. while the C group did not. Both groups received routine rehabilitation schedule. The Functional Independence Measure was used to measure outcome at the first, 14th and the 28th day of rehabilitation ward admitted. Data were analyzed using SPSS 22.0. After implementation of standardized ‘‘bedside rehabilitation program’, the results were: (1) the increasing of bedside rehabilitation had significant difference (p<.05) in promotion ADL function of stroke patients (2) the extend time of the bedside rehabilitation has significant difference (p<.05) in promotion ADL function of stroke patients compared with the control group. This study demonstrated that the ‘bedside rehabilitation program’ enhanced the ADL function in stroke patients. The nurses and rehabilitation ward managers need to understand that the extend time and frequency of rehabilitation provide a chance to enhanced the ADL function of stroke patients.

Keywords: stroke, bedside rehabilitation, functional activity, ADL

Procedia PDF Downloads 137
20891 Forecasting Amman Stock Market Data Using a Hybrid Method

Authors: Ahmad Awajan, Sadam Al Wadi

Abstract:

In this study, a hybrid method based on Empirical Mode Decomposition and Holt-Winter (EMD-HW) is used to forecast Amman stock market data. First, the data are decomposed by EMD method into Intrinsic Mode Functions (IMFs) and residual components. Then, all components are forecasted by HW technique. Finally, forecasting values are aggregated together to get the forecasting value of stock market data. Empirical results showed that the EMD- HW outperform individual forecasting models. The strength of this EMD-HW lies in its ability to forecast non-stationary and non- linear time series without a need to use any transformation method. Moreover, EMD-HW has a relatively high accuracy comparing with eight existing forecasting methods based on the five forecast error measures.

Keywords: Holt-Winter method, empirical mode decomposition, forecasting, time series

Procedia PDF Downloads 133
20890 Assessment of ASEI-PDSI Method on Students’ Attitude and Achievement in Junior Secondary Schools Mathematics in FCT-Abuja

Authors: Amenaghawon Clement Osemwinyen

Abstract:

The Activity, Student-centred, Experiment, Improvisation - Plan, Do, See, Improve (ASEI-PDSI) method championed by the Strengthening Mathematics And Science Education (SMASE) - Nigeria Project is an attempt to improve the quality of mathematics, which has consistently declined over the years in both public primary and secondary schools across the country. The study thus assessed the ASEI-PDSI method on students’ attitudes and achievement in junior secondary schools (JSS) mathematics in FCT-Abuja. A survey research design was adopted, and 100 mathematics teachers using a stratified random sampling method were used for the study. The data were collected using structured questionnaires and analyzed using descriptive statistics. The findings showed that the ASEI-PDSI method had significantly improved the attitudes of students toward mathematics. The study also revealed that the ASEI-PDSI method significantly influenced junior secondary school (JSS) students’ mathematics achievement. Amongst the recommendations were that teachers should be encouraged to adopt the ASEI-PDSI method in teaching and learning mathematics in order to create a mathematically stimulating classroom environment which could advertently influence junior secondary school (JSS) students’ attitude and academic performance in mathematics. Also, regular in-service training programs should be organized by stakeholders (government and other interest groups) so as to improve the teaching strategies of teachers, mostly as they affect the ASEI-PDSI method.

Keywords: achievement, ASEI-PDSI method, attitude, mathematics, SMASE

Procedia PDF Downloads 120
20889 Additive Weibull Model Using Warranty Claim and Finite Element Analysis Fatigue Analysis

Authors: Kanchan Mondal, Dasharath Koulage, Dattatray Manerikar, Asmita Ghate

Abstract:

This paper presents an additive reliability model using warranty data and Finite Element Analysis (FEA) data. Warranty data for any product gives insight to its underlying issues. This is often used by Reliability Engineers to build prediction model to forecast failure rate of parts. But there is one major limitation in using warranty data for prediction. Warranty periods constitute only a small fraction of total lifetime of a product, most of the time it covers only the infant mortality and useful life zone of a bathtub curve. Predicting with warranty data alone in these cases is not generally provide results with desired accuracy. Failure rate of a mechanical part is driven by random issues initially and wear-out or usage related issues at later stages of the lifetime. For better predictability of failure rate, one need to explore the failure rate behavior at wear out zone of a bathtub curve. Due to cost and time constraints, it is not always possible to test samples till failure, but FEA-Fatigue analysis can provide the failure rate behavior of a part much beyond warranty period in a quicker time and at lesser cost. In this work, the authors proposed an Additive Weibull Model, which make use of both warranty and FEA fatigue analysis data for predicting failure rates. It involves modeling of two data sets of a part, one with existing warranty claims and other with fatigue life data. Hazard rate base Weibull estimation has been used for the modeling the warranty data whereas S-N curved based Weibull parameter estimation is used for FEA data. Two separate Weibull models’ parameters are estimated and combined to form the proposed Additive Weibull Model for prediction.

Keywords: bathtub curve, fatigue, FEA, reliability, warranty, Weibull

Procedia PDF Downloads 74
20888 A Stable Method for Determination of the Number of Independent Components

Authors: Yuyan Yi, Jingyi Zheng, Nedret Billor

Abstract:

Independent component analysis (ICA) is one of the most commonly used blind source separation (BSS) techniques for signal pre-processing, such as noise reduction and feature extraction. The main parameter in the ICA method is the number of independent components (IC). Although there have been several methods for the determination of the number of ICs, it has not been given sufficient attentionto this important parameter. In this study, wereview the mostused methods fordetermining the number of ICs and providetheir advantages and disadvantages. Further, wepropose an improved version of column-wise ICAByBlock method for the determination of the number of ICs.To assess the performance of the proposed method, we compare the column-wise ICAbyBlock with several existing methods through different ICA methods by using simulated and real signal data. Results show that the proposed column-wise ICAbyBlock is an effective and stable method for determining the optimal number of components in ICA. This method is simple, and results can be demonstrated intuitively with good visualizations.

Keywords: independent component analysis, optimal number, column-wise, correlation coefficient, cross-validation, ICAByblock

Procedia PDF Downloads 100
20887 The Numerical and Experimental Analysis of Compressed Composite Plate in Asymmetrical Arrangement of Layers

Authors: Katarzyna Falkowicz

Abstract:

The work focused on the original concept of a thin-walled plate element with a cut-out, for use as a spring or load-bearing element. The subject of the study were rectangular plates with a cut-out with variable geometrical parameters and with a variable angle of fiber arrangement, made of a carbon-epoxy composite with high strength properties in an asymmetrical arrangement, subjected to uniform compression. The influence of geometrical parameters of the cut-out and the angle of fiber arrangement on the value of critical load of the structure and buckling form was investigated. Uniform thin plates are relatively cheap to manufacture, however due to their low bending stiffness; they can carry relatively small loads. The lowest form of loss of plate stability, which is the bending form, leads to its rapid destruction due to high deflection increases, with a slight increase in compressive load - low rigidity of the structure. However, the stiffness characteristics of the structure change significantly when the work of plate is forcing according to the higher flexural-torsional form of buckling. The plate is able to carry a much higher compressive load while maintaining much stiffer work characteristics in the post-critical range. The calculations carried out earlier show that plates with forced higher form of buckling are characterized by stable, progressive paths of post-critical equilibrium, enabling their use as elastic elements. The characteristics of such elements can be designed in a wide range by changing the geometrical parameters of the cut-out, i.e. height and width as well as by changing the angle of fiber arrangement The commercial ABAQUS program using the finite element method was used to develop the discrete model and perform numerical calculations. The obtained results are of significant practical importance in the design of structures with elastic elements, allowing to achieve the required maintenance characteristics of the device.

Keywords: buckling mode, numerical method, unsymmetrical laminates, thin-walled elastic elements

Procedia PDF Downloads 107
20886 Effectiveness of an Attachment-Based Intervention on Child Cognitive Development: Preliminary Analyses of a 12-Month Follow-Up

Authors: Claire Baudry, Jessica Pearson, Laura-Emilie Savage, George Tarbulsy

Abstract:

Introduction: Over the last decade, researchers have implemented attachment-based interventions to promote parental interactive sensitivity and child development among vulnerable families. In the context of the present study, these interventions have been shown to be effective to enhance cognitive development when child outcome was measured shortly after the intervention. Objectives: The goal of the study was to investigate the effects of an attachment-based intervention on child cognitive development one year post-intervention. Methods: Thirty-five mother-child dyads referred by Child Protective Services in the province of Québec, Canada, were included in this study: 21 dyads who received 6 to 8 intervention sessions and 14 dyads not exposed to the intervention and matched for the following variables: duration of child protective services, reason for involvement with child protection, age, sex and family status. Child cognitive development was measured using the WPPSI-IV, 12 months after the end of the intervention when the average age of children was 54 months old. Findings: An independent-samples t-test was conducted to compare the scores obtained on the WPPSI-IV for the two groups. In general, no differences were observed between the two groups. There was a significant difference on the fluid reasoning scale between children exposed to the intervention (M = 95,13, SD = 16,67) and children not exposed (M = 81, SD = 9,90). T (23) = -2,657; p= .014 (IC :-25.13;3.12). This difference was found only for children aged between 48 and 92 months old. Other results did not show any significant difference between the two groups (Global IQ or subscales). Conclusions: This first set of analyses suggest that relatively little effects of attachment-based intervention remain on the level of cognitive functioning 12-months post-intervention. It is possible that the significant findings concerning fluid reasoning may be pertinent in that fluid reasoning is linked to the capacity to analyse, to solve problems, and remember information, which may be important for promoting school readiness. As the study is completed and as more information is gained from other assessments of cognitive and socioemotional outcome, a clearer picture of the potential moderate-term impact of attachment-based intervention will emerge.

Keywords: attachment-based intervention, child development, child protective services, cognitive development

Procedia PDF Downloads 175
20885 Numerical Study of Natural Convection in a Nanofluid-Filled Vertical Cylinder under an External Magnetic Field

Authors: M. Maache, R. Bessaih

Abstract:

In this study, the effect of the magnetic field direction on the free convection heat transfer in a vertical cylinder filled with an Al₂O₃ nanofluid is investigated numerically. The external magnetic field is applied in either direction axial and radial on a cylinder having an aspect ratio H/R0=5, bounded by the top and the bottom disks at temperatures Tc and Th and by an adiabatic side wall. The equations of continuity, Navier Stocks and energy are non-dimensionalized and then discretized by the finite volume method. A computer program based on the SIMPLER algorithm is developed and compared with the numerical results found in the literature. The numerical investigation is carried out for different governing parameters namely: The Hartmann number (Ha=0, 5, 10, …, 40), nanoparticles volume fraction (ϕ=0, 0.025, …,0.1) and Rayleigh number (Ra=103, Ra=104 and Ra=105). The behavior of average Nusselt number, streamlines and temperature contours are illustrated. The results revel that the average Nusselt number increases with an increase of the Rayleigh number but it decreases with an increase in the Hartmann number. Depending on the magnetic field direction and on the values of Hartmann and Rayleigh numbers, an increase of the solid volume fraction may result enhancement or deterioration of the heat transfer performance in the nanofluid.

Keywords: natural convection, nanofluid, magnetic field, vertical cylinder

Procedia PDF Downloads 315
20884 Temporal Variation of Shorebirds Population in Two Different Mudflats Areas

Authors: N. Norazlimi, R. Ramli

Abstract:

A study was conducted to determine the diversity and abundance of shorebird species habituating the mudflat area of Jeram Beach and Remis Beach, Selangor, Peninsular Malaysia. Direct observation technique (using binoculars and video camera) was applied to record the presence of bird species in the sampling sites from August 2013 until July 2014. A total of 32 species of shorebird were recorded during both migratory and non-migratory seasons. Of these, eleven species (47.8%) are migrants, six species (26.1%) have both migrant and resident populations, four species (17.4%) are vagrants and two species (8.7%) are residents. The compositions of the birds differed significantly in all months (χ2=84.35, p<0.001). There is a significant difference in avian abundance between migratory and non-migratory seasons (Mann-Whitney, t=2.39, p=0.036). The avian abundance were differed significantly in Jeram and Remis Beaches during migratory periods (t=4.39, p=0.001) but not during non-migratory periods (t=0.78, p=0.456). Shorebird diversity was also affected by tidal cycle. There is a significance difference between high tide and low tide (Mann-Whitney, t=78.0, p<0.005). Frequency of disturbance also affected the shorebird distribution (Mann-Whitney, t=57.0, p= 0.0134). Therefore, this study concluded that tides and disturbances are two factors that affecting temporal distribution of shorebird in mudflats area.

Keywords: biodiversity, distribution, migratory birds, direct observation

Procedia PDF Downloads 393
20883 The Use of Stochastic Gradient Boosting Method for Multi-Model Combination of Rainfall-Runoff Models

Authors: Phanida Phukoetphim, Asaad Y. Shamseldin

Abstract:

In this study, the novel Stochastic Gradient Boosting (SGB) combination method is addressed for producing daily river flows from four different rain-runoff models of Ohinemuri catchment, New Zealand. The selected rainfall-runoff models are two empirical black-box models: linear perturbation model and linear varying gain factor model, two conceptual models: soil moisture accounting and routing model and Nedbør-Afrstrømnings model. In this study, the simple average combination method and the weighted average combination method were used as a benchmark for comparing the results of the novel SGB combination method. The models and combination results are evaluated using statistical and graphical criteria. Overall results of this study show that the use of combination technique can certainly improve the simulated river flows of four selected models for Ohinemuri catchment, New Zealand. The results also indicate that the novel SGB combination method is capable of accurate prediction when used in a combination method of the simulated river flows in New Zealand.

Keywords: multi-model combination, rainfall-runoff modeling, stochastic gradient boosting, bioinformatics

Procedia PDF Downloads 340
20882 Concept of a Pseudo-Lower Bound Solution for Reinforced Concrete Slabs

Authors: M. De Filippo, J. S. Kuang

Abstract:

In construction industry, reinforced concrete (RC) slabs represent fundamental elements of buildings and bridges. Different methods are available for analysing the structural behaviour of slabs. In the early ages of last century, the yield-line method has been proposed to attempt to solve such problem. Simple geometry problems could easily be solved by using traditional hand analyses which include plasticity theories. Nowadays, advanced finite element (FE) analyses have mainly found their way into applications of many engineering fields due to the wide range of geometries to which they can be applied. In such cases, the application of an elastic or a plastic constitutive model would completely change the approach of the analysis itself. Elastic methods are popular due to their easy applicability to automated computations. However, elastic analyses are limited since they do not consider any aspect of the material behaviour beyond its yield limit, which turns to be an essential aspect of RC structural performance. Furthermore, their applicability to non-linear analysis for modeling plastic behaviour gives very reliable results. Per contra, this type of analysis is computationally quite expensive, i.e. not well suited for solving daily engineering problems. In the past years, many researchers have worked on filling this gap between easy-to-implement elastic methods and computationally complex plastic analyses. This paper aims at proposing a numerical procedure, through which a pseudo-lower bound solution, not violating the yield criterion, is achieved. The advantages of moment distribution are taken into account, hence the increase in strength provided by plastic behaviour is considered. The lower bound solution is improved by detecting over-yielded moments, which are used to artificially rule the moment distribution among the rest of the non-yielded elements. The proposed technique obeys Nielsen’s yield criterion. The outcome of this analysis provides a simple, yet accurate, and non-time-consuming tool of predicting the lower-bound solution of the collapse load of RC slabs. By using this method, structural engineers can find the fracture patterns and ultimate load bearing capacity. The collapse triggering mechanism is found by detecting yield-lines. An application to the simple case of a square clamped slab is shown, and a good match was found with the exact values of collapse load.

Keywords: computational mechanics, lower bound method, reinforced concrete slabs, yield-line

Procedia PDF Downloads 180
20881 Numerical Analysis of Prefabricated Horizontal Drain Induced Consolidation Using ABAQUS

Authors: Anjana R. Menon, Anjana Bhasi

Abstract:

This paper deals with the numerical analysis of Prefabricated Horizontal Drain (PHD) induced consolidation of clayey deposits, using ABAQUS. PHDs are much like Prefabricated Vertical Drains (PVDs) installed in horizontal layers, used mainly for enhancing the consolidation of clayey fill embankments, and dredged mud deposits. The efficiency of the system depends mainly on the spacing and layout of the drain. Hence, two spacing related parameters are defined, namely WH (width to horizontal spacing ratio) and VH (vertical to horizontal spacing ratio), and the finite element models are developed based on plane strain unit cell conditions under various combinations of these parameters. The analysis results, in terms of degree of consolidation (U), are compared with the established theories. Based on the analysis, a set of equations are proposed to analyse the PHD induced consolidation. The proposed method is found to be reasonably accurate. Further, the effect of PHDs at different spacing ratios, in accelerating consolidation of a clayey embankment fill is analysed in terms of pore pressure dissipation rate, and settlement. The PHD is found to accelerate the rate of pore pressure dissipation by more than 50%, thus reducing the time for final settlement significantly.

Keywords: ABAQUS, consolidation, plane strain, prefabricated horizontal drain

Procedia PDF Downloads 363
20880 Stable Tending Control of Complex Power Systems: An Example of Localized Design of Power System Stabilizers

Authors: Wenjuan Du

Abstract:

The phase compensation method was proposed based on the concept of the damping torque analysis (DTA). It is a method for the design of a PSS (power system stabilizer) to suppress local-mode power oscillations in a single-machine infinite-bus power system. This paper presents the application of the phase compensation method for the design of a PSS in a multi-machine power system. The application is achieved by examining the direct damping contribution of the stabilizer to the power oscillations. By using linearized equal area criterion, a theoretical proof to the application for the PSS design is presented. Hence PSS design in the paper is an example of stable tending control by localized method.

Keywords: phase compensation method, power system small-signal stability, power system stabilizer

Procedia PDF Downloads 642
20879 Analysis of Natural Convection within a Hexagonal Enclosure Full with Nanofluid (Water-Cu) Under Effect of the Position of the Inner Obstacle

Authors: Lakhdar Rahmani, Benhanifia Kada, Brahim Mebarki

Abstract:

The present paper aims to investigate the natural convection of nanofluid (water-cu) inside a hexagonal enclosure shape embedded with a square obstacle in the presence of hot and cold side walls. The governing equations were solved in a non-uniform unstructured grid by employing the Galerkin finite element method using the software COMSOL Multiphysics. The objective of this study is to analyze the influence of Rayleigh number (103 < Ra < 105), the position of the obstacle, which is located in three different positions (center, bottom, and top side ), and the effect of Nanoparticles volume concentration (0 < Ø < 0.2) on the thermal behavior inside the enclosure, The results are reported as contours of isotherms, streamlines, and average Nusselt numbers. The obtained results illustrate that the increase in the Rayleigh number (Ra) and the Nanoparticles concentration ( Ø ) leads to an increase in the Nusselt number (Nu average ) that signifies the rate of heat transfer in the studied enclosure, in addition to the best performance observed with the position of obstacle that is located at the middle of the enclosure, where has a high effect in improving the heat transfer along the enclosure comparatively with the rest different positions.

Keywords: natural convection, nanofluid (water-Cu), hexagonal enclosure, Nusselt numbers, Rayleigh number

Procedia PDF Downloads 92
20878 Analysis of Compressive and Tensile Response of Pumpkin Flesh, Peel and Unpeeled Tissues Using Experimental and FEA

Authors: Maryam Shirmohammadi, Prasad K. D. V. Yarlagadda, YuanTong Gu

Abstract:

The mechanical damage on the agricultural crop during and after harvesting can create high volume of damage on tissue. Uniaxial compression and tensile loading were performed on flesh and peel samples of pumpkin. To investigate the structural changes on the tissue, Scanning Electron Microscopy (SEM) was used to capture the cellular structure change before and after loading on tissue for tensile, compression and indentation tests. To obtain required mechanical properties of tissue for the finite element analysis (FEA) model, laser measurement sensors were used to record the lateral displacement of tissue under the compression loading. Uniaxial force versus deformation data were recorded using Universal Testing Machine for both tensile and compression tests. The experimental Results were employed to develop a material model with failure criteria. The results obtained by the simulation were compared with those obtained by experiments. Note that although modelling food materials’ behaviour is not a new concept however, majority of previous studies focused on elastic behaviour and damages under linear limit, this study, however, has developed FEA models for tensile and compressive loading of pumpkin flesh and peel samples using, as the first study, both elastic and elasto-plastic material types. In addition, pumpkin peel and flesh tissues were considered as two different materials with different properties under mechanical loadings. The tensile and compression loadings were used to develop the material model for a composite structure for FEA model of mechanical peeling of pumpkin as a tough skinned vegetable.

Keywords: compressive and tensile response, finite element analysis, poisson’s ratio, elastic modulus, elastic and plastic response, rupture and bio-yielding

Procedia PDF Downloads 331
20877 Design and Construction of a Solar Mobile Anaerobic Digestor for Rural Communities

Authors: César M. Moreira, Marco A. Pazmiño-Hernández, Marco A. Pazmiño-Barreno, Kyle Griffin, Pratap Pullammanappallil

Abstract:

An anaerobic digestion system that was completely operated on solar power (both photovoltaic and solar thermal energy), and mounted on a trailer to make it mobile, was designed and constructed. A 55-gallon batch digester was placed within a chamber that was heated by hot water pumped through a radiator. Hot water was produced by a solar thermal collector and photovoltaic panels charged a battery which operated pumps for recirculating water. It was found that the temperature in the heating chamber was maintained above ambient temperature but it follows the same trend as ambient temperature. The temperature difference between the chamber and ambient values was not constant but varied with time of day. Advantageously, the temperature difference was highest during night and early morning and lowest near noon. In winter, when ambient temperature dipped to 2 °C during early morning hours, the chamber temperature did not drop below 10 °C. Model simulations showed that even if the digester is subjected to diurnal variations of temperature (as observed in winter of a subtropical region), about 63 % of the waste that would have been processed under constant digester temperature of 38 °C, can still be processed. The cost of the digester system without the trailer was $1,800.

Keywords: anaerobic digestion, solar-mobile, rural communities, solar, hybrid

Procedia PDF Downloads 278
20876 Drying Effect on the Proximate Composition and Functional Properties of Cocoyam Flour

Authors: K. Maliki, A. Ajayi, O. M. Makanjuola, O. J. Adebowale

Abstract:

Cocoyam is herbaceous perennial plant which belongs to the family Araceae and genus xanthosoma or cococasia is mostly cultivated as food crop. It is very rich in Vitamin B6, Magnesium and also in dietary fiber. Matured cocoyam is eaten boiled, Fried or roasted in Nigeria. It can also be dried and used to make flour. Food drying is a method of food preservation in which food is dried, thus inhibit the growth of bacteria yeast and mold through the removal of water. Drying effect on the proximate composition and functional properties of cocoyam flour were investigated. Freshly harvested cocoyam cultivars at matured level were washed with portable water, peeled, sliced into 0.3mm thickness blanch in boiling water at 100°C for 15 minutes and dried using sun drying oven and cabinet dryers. The blanched slices were divided into three lots and were subjected to different drying methods. The dried cocoyam slices were milled into flour using Apex mill and packed into Low Density Polyethylene Film (LDPE) 75 Micron 4 thickness and kept for four months under ambient temperature before analysis. The results showed that the moisture content, ash, crude fiber, fat, protein and carbohydrate ranged from 7.35% to 13.89%, 1.45% to 3.3%, 1.2% to 3.41%, 2.1% to 3.1%, 6.30% to 9.1% and 66% to 82% respectively. The functional properties of the cocoyam flour ranged from 1. 65ml/g to 4.24ml/g water absorption capacity, 0.85ml/g to 2.11ml/g oil absorption capacity 0.56ml/g and 0.78ml/g bulk density and 4.91% to 6.80% swelling capacity. The result showed that there was not significant difference (P ≥ 0.5) across the various drying methods used. Cabinet drying method was found to have the best quality characteristic values than the other drying methods. In conclusion, drying of cocoyam could be used for value addition and provide extension to shelf-life.

Keywords: cocoyam flour, drying, cabinet dryer, oven dryer

Procedia PDF Downloads 249
20875 The Influence of Steel Connection on Fire Resistance of Composite Steel-Framed Buildings

Authors: Mohammed Kadhim, Zhaohui Huang

Abstract:

Steel connections can play an important role in enhancing the robustness of structures under fire conditions. Therefore, it is significant to examine the influence of steel connections on the fire resistance of composite steel-framed buildings. In this paper, both the behavior of steel connections and their influence on composite steel frame are analyzed using the non-linear finite element computer software VULCAN at ambient and elevated temperatures. The chosen frame is subjected to ISO834 fire. The comparison between end plate connections, pinned connection, and rigid connection has been carried out. By applying different compartment fires, some cases are studied to show the behavior of steel connection when the fire is applied at certain beams. In addition, different plate thickness and deferent applied loads have been analyzed to examine the behavior of chosen steel connection under ISO834 fire. It was found from the analytical results that the beam with extended end plate is stronger and has better performance in terms of axial forces than those beams with flush end plate connection. It was also found that extended end plate connection has highest limiting temperatures compared to the flush end plate connection. In addition, it was found that the performance of end-plate connections is very close to rigid connection and very far from pinned connections. Furthermore, plate thickness has less effect on the influence of steel connection on fire resistance. In conclusion, the behavior of composite steel framed buildings is largely dependent on the steel connection due to their high impact under fire condition. It is recommended to consider the extended end-plate in the design proposes because of its higher properties compared to the flush end plate connection. Finally, this paper shows a steel connection has an important effect on the fire resistance of composite steel framed buildings.

Keywords: composite steel-framed buildings, connection behavior, end-plate connections, finite element modeling, fire resistance

Procedia PDF Downloads 161
20874 Assessment of Aminopolyether on 18F-FDG Samples

Authors: Renata L. C. Leão, João E. Nascimento, Natalia C. E. S. Nascimento, Elaine S. Vasconcelos, Mércia L. Oliveira

Abstract:

The quality control procedures of a radiopharmaceutical include the assessment of its chemical purity. The method suggested by international pharmacopeias consists of a thin layer chromatographic run. In this paper, the method proposed by the United States Pharmacopeia (USP) is compared to a direct method to determine the final concentration of aminopolyether in Fludeoxyglucose (18F-FDG) preparations. The approach (no chromatographic run) was achieved by placing the thin-layer chromatography (TLC) plate directly on an iodine vapor chamber. Both methods were validated and they showed adequate results to determine the concentration of aminopolyether in 18F-FDG preparations. However, the direct method is more sensitive, faster and simpler when compared to the reference method (with chromatographic run), and it may be chosen for use in routine quality control of 18F-FDG.

Keywords: chemical purity, Kryptofix 222, thin layer chromatography, validation

Procedia PDF Downloads 203
20873 An Efficient Collocation Method for Solving the Variable-Order Time-Fractional Partial Differential Equations Arising from the Physical Phenomenon

Authors: Haniye Dehestani, Yadollah Ordokhani

Abstract:

In this work, we present an efficient approach for solving variable-order time-fractional partial differential equations, which are based on Legendre and Laguerre polynomials. First, we introduced the pseudo-operational matrices of integer and variable fractional order of integration by use of some properties of Riemann-Liouville fractional integral. Then, applied together with collocation method and Legendre-Laguerre functions for solving variable-order time-fractional partial differential equations. Also, an estimation of the error is presented. At last, we investigate numerical examples which arise in physics to demonstrate the accuracy of the present method. In comparison results obtained by the present method with the exact solution and the other methods reveals that the method is very effective.

Keywords: collocation method, fractional partial differential equations, legendre-laguerre functions, pseudo-operational matrix of integration

Procedia PDF Downloads 168
20872 Adaptive Nonparametric Approach for Guaranteed Real-Time Detection of Targeted Signals in Multichannel Monitoring Systems

Authors: Andrey V. Timofeev

Abstract:

An adaptive nonparametric method is proposed for stable real-time detection of seismoacoustic sources in multichannel C-OTDR systems with a significant number of channels. This method guarantees given upper boundaries for probabilities of Type I and Type II errors. Properties of the proposed method are rigorously proved. The results of practical applications of the proposed method in a real C-OTDR-system are presented in this report.

Keywords: guaranteed detection, multichannel monitoring systems, change point, interval estimation, adaptive detection

Procedia PDF Downloads 450
20871 2D Numerical Modeling for Induced Current Distribution in Soil under Lightning Impulse Discharge

Authors: Fawwaz Eniola Fajingbesi, Nur Shahida Midia, Elsheikh M. A. Elsheikh, Siti Hajar Yusoff

Abstract:

Empirical analysis of lightning related phenomena in real time is extremely dangerous due to the relatively high electric discharge involved. Hence, design and optimization of efficient grounding systems depending on real time empirical methods are impeded. Using numerical methods, the dynamics of complex systems could be modeled hence solved as sets of linear and non-linear systems . In this work, the induced current distribution as lightning strike traverses the soil have been numerically modeled in a 2D axial-symmetry and solved using finite element method (FEM) in COMSOL Multiphysics 5.2 AC/DC module. Stratified and non- stratified electrode system were considered in the solved model and soil conductivity (σ) varied between 10 – 58 mS/m. The result discussed therein were the electric field distribution, current distribution and soil ionization phenomena. It can be concluded that the electric field and current distribution is influenced by the injected electric potential and the non-linearity in soil conductivity. The result from numerical calculation also agrees with previously laboratory scale empirical results.

Keywords: current distribution, grounding systems, lightning discharge, numerical model, soil conductivity, soil ionization

Procedia PDF Downloads 313
20870 A Comparative Study of Wellness Among Sportsmen and Non Sportsmen

Authors: Jaskaran Singh Sidhu

Abstract:

Aim: The purpose of this study is to find the relationship between wellness among sportsmen and non sportsmen. Methodology: The present study is an experimental study for 80 senior secondary volleyball players of 16-19 years of age from Ludhiana District of Punjab (India), and 80 non-sportsperson were taken from senior secondary school of Ludhiana district. The sample for this study was taken through a random sampling technique. Tools: A five point scale havinf 50 items was used to acess the wellness Statistical Analysis: To find out the relationship among the variables exists or not, a t-test was used to test the significance of the difference between the means. Statistics for each characteristic were calculated; Mean, Standard deviation, Standard error of Mean. Data were analyzed using SPSS (statistical package for the social sciences). Statistical significance was set at p < 0.05. Results: Substantial deviations were noted at p<0.5 in the totality of wellness. Sportsmen show significant differences exist at p<0.5 in three parameters of wellness i.e., physical wellness, mental wellness, and social wellness. In spiritual and emotional wellness attributes, non-sportsmen shows significant difference at p<0.5. Conclusion: From the data interpretation it reflects that overall wellness can be improved by participation in sports. It further noted in study that participation in sports promote the attributes of wellness i.e., physical wellness, mental wellness, emotional wellness and social wellness.

Keywords: physical, mental, social, emotional, wellness, spiritual

Procedia PDF Downloads 91
20869 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 81
20868 State Estimation Method Based on Unscented Kalman Filter for Vehicle Nonlinear Dynamics

Authors: Wataru Nakamura, Tomoaki Hashimoto, Liang-Kuang Chen

Abstract:

This paper provides a state estimation method for automatic control systems of nonlinear vehicle dynamics. A nonlinear tire model is employed to represent the realistic behavior of a vehicle. In general, all the state variables of control systems are not precisedly known, because those variables are observed through output sensors and limited parts of them might be only measurable. Hence, automatic control systems must incorporate some type of state estimation. It is needed to establish a state estimation method for nonlinear vehicle dynamics with restricted measurable state variables. For this purpose, unscented Kalman filter method is applied in this study for estimating the state variables of nonlinear vehicle dynamics. The objective of this paper is to propose a state estimation method using unscented Kalman filter for nonlinear vehicle dynamics. The effectiveness of the proposed method is verified by numerical simulations.

Keywords: state estimation, control systems, observer systems, nonlinear systems

Procedia PDF Downloads 139
20867 Model of Cosserat Continuum Dispersion in a Half-Space with a Scatterer

Authors: Francisco Velez, Juan David Gomez

Abstract:

Dispersion effects on the Scattering for a semicircular canyon in a micropolar continuum are analyzed, by using a computational finite element scheme. The presence of microrotational waves and the dispersive SV waves affects the propagation of elastic waves. Here, a contrast with the classic model is presented, and the dependence with the micropolar parameters is studied.

Keywords: scattering, semicircular canyon, wave dispersion, micropolar medium, FEM modeling

Procedia PDF Downloads 547
20866 Design and Fabrication of Stiffness Reduced Metallic Locking Compression Plates through Topology Optimization and Additive Manufacturing

Authors: Abdulsalam A. Al-Tamimi, Chris Peach, Paulo Rui Fernandes, Paulo J. Bartolo

Abstract:

Bone fixation implants currently used to treat traumatic fractured bones and to promote fracture healing are built with biocompatible metallic materials such as stainless steel, cobalt chromium and titanium and its alloys (e.g., CoCrMo and Ti6Al4V). The noticeable stiffness mismatch between current metallic implants and host bone associates with negative outcomes such as stress shielding which causes bone loss and implant loosening leading to deficient fracture treatment. This paper, part of a major research program to design the next generation of bone fixation implants, describes the combined use of three-dimensional (3D) topology optimization (TO) and additive manufacturing powder bed technology (Electron Beam Melting) to redesign and fabricate the plates based on the current standard one (i.e., locking compression plate). Topology optimization is applied with an objective function to maximize the stiffness and constraint by volume reductions (i.e., 25-75%) in order to obtain optimized implant designs with reduced stress shielding phenomenon, under different boundary conditions (i.e., tension, bending, torsion and combined loads). The stiffness of the original and optimised plates are assessed through a finite-element study. The TO results showed actual reduction in the stiffness for most of the plates due to the critical values of volume reduction. Additionally, the optimized plates fabricated using powder bed techniques proved that the integration between the TO and additive manufacturing presents the capability of producing stiff reduced plates with acceptable tolerances.

Keywords: additive manufacturing, locking compression plate, finite element, topology optimization

Procedia PDF Downloads 202