Search results for: kinetic energy loss
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 11746

Search results for: kinetic energy loss

11566 Wind Energy Loss Phenomenon Over Volumized Building Envelope with Porous Air Portals

Authors: Ying-chang Yu, Yuan-lung Lo

Abstract:

More and more building envelopes consist of the construction of balconies, canopies, handrails, sun-shading, vertical planters or gardens, maintenance platforms, display devices, lightings, ornaments, and also the most commonly seen double skin system. These components form a uniform but three-dimensional disturbance structure and create a complex surface wind field in front of the actual watertight building interface. The distorted wind behavior would affect the façade performance and building ventilation. Comparing with sole windscreen walls, these three-dimensional structures perform like distributed air portal assembly, and each portal generates air turbulence and consume wind pressure and energy simultaneously. In this study, we attempted to compare the behavior of 2D porous windscreens without internal construction, porous tubular portal windscreens, porous tapered portal windscreens, and porous coned portal windscreens. The wind energy reduction phenomenon is then compared to the different distributed air portals. The experiments are conducted in a physical wind tunnel with 1:25 in scale to simulate the three-dimensional structure of a real building envelope. The experimental airflow was set up to smooth flow. The specimen is designed as a plane with a distributed tubular structure behind, and the control group uses different tubular shapes but the same fluid volume to observe the wind damping phenomenon of various geometries.

Keywords: volumized building envelope, porous air portal, wind damping, wind tunnel test, wind energy loss

Procedia PDF Downloads 132
11565 Assessment of Kinetic Trajectory of the Median Nerve from Wrist Ultrasound Images Using Two Dimensional Baysian Speckle Tracking Technique

Authors: Li-Kai Kuo, Shyh-Hau Wang

Abstract:

The kinetic trajectory of the median nerve (MN) in the wrist has shown to be capable of being applied to assess the carpal tunnel syndrome (CTS), and was found able to be detected by high-frequency ultrasound image via motion tracking technique. Yet, previous study may not quickly perform the measurement due to the use of a single element transducer for ultrasound image scanning. Therefore, previous system is not appropriate for being applied to clinical application. In the present study, B-mode ultrasound images of the wrist corresponding to movements of fingers from flexion to extension were acquired by clinical applicable real-time scanner. The kinetic trajectories of MN were off-line estimated utilizing two dimensional Baysian speckle tracking (TDBST) technique. The experiments were carried out from ten volunteers by ultrasound scanner at 12 MHz frequency. Results verified from phantom experiments have demonstrated that TDBST technique is able to detect the movement of MN based on signals of the past and present information and then to reduce the computational complications associated with the effect of such image quality as the resolution and contrast variations. Moreover, TDBST technique tended to be more accurate than that of the normalized cross correlation tracking (NCCT) technique used in previous study to detect movements of the MN in the wrist. In response to fingers’ flexion movement, the kinetic trajectory of the MN moved toward the ulnar-palmar direction, and then toward the radial-dorsal direction corresponding to the extensional movement. TDBST technique and the employed ultrasound image scanner have verified to be feasible to sensitively detect the kinetic trajectory and displacement of the MN. It thus could be further applied to diagnose CTS clinically and to improve the measurements to assess 3D trajectory of the MN.

Keywords: baysian speckle tracking, carpal tunnel syndrome, median nerve, motion tracking

Procedia PDF Downloads 494
11564 Comparative Study of Electronic and Optical Properties of Ammonium and Potassium Dinitramide Salts through Ab-Initio Calculations

Authors: J. Prathap Kumar, G. Vaitheeswaran

Abstract:

The present study investigates the role of ammonium and potassium ion in the electronic, bonding and optical properties of dinitramide salts due to their stability and non-toxic nature. A detailed analysis of bonding between NH₄ and K with dinitramide, optical transitions from the valence band to the conduction band, absorption spectra, refractive indices, reflectivity, loss function are reported. These materials are well known as oxidizers in solid rocket propellants. In the present work, we use full potential linear augmented plane wave (FP-LAPW) method which is implemented in the Wien2k package within the framework of density functional theory. The standard DFT functional local density approximation (LDA) and generalized gradient approximation (GGA) always underestimate the band gap by 30-40% due to the lack of derivative discontinuities of the exchange-correlation potential with respect to an occupation number. In order to get reliable results, one must use hybrid functional (HSE-PBE), GW calculations and Tran-Blaha modified Becke-Johnson (TB-mBJ) potential. It is very well known that hybrid functionals GW calculations are very expensive, the later methods are computationally cheap. The new developed TB-mBJ functionals use information kinetic energy density along with the charge density employed in DFT. The TB-mBJ functionals cannot be used for total energy calculations but instead yield very much improved band gap. The obtained electronic band gap at gamma point for both the ammonium dinitramide and potassium dinitramide are found to be 2.78 eV and 3.014 eV with GGA functional, respectively. After the inclusion of TB-mBJ, the band gap improved by 4.162 eV for potassium dinitramide and 4.378 eV for ammonium dinitramide. The nature of the band gap is direct in ADN and indirect in KDN. The optical constants such as dielectric constant, absorption, and refractive indices, birefringence values are presented. Overall as there are no experimental studies we present the improved band gap with TB-mBJ functional following with optical properties.

Keywords: ammonium dinitramide, potassium dinitramide, DFT, propellants

Procedia PDF Downloads 156
11563 Investigation on the Kinetic Mechanism of the Reduction of Fe₂O₃/CoO-Decorated Carbon Xerogel

Authors: Mohammad Reza Ghaani, Michele Catti

Abstract:

The reduction of CoO/Fe₂O₃ oxides supported on carbon xerogels was studied to elucidate the effect of nano-size distribution of the catalyst in carbon matrices. Resorcinol formaldehyde xerogels were synthesized, impregnated with iron and cobalt nitrates, and subsequently heated to obtain the oxides. The mechanism of oxide reduction to metal was investigated by in-situ synchrotron X-ray diffraction in dynamic, non-isothermal conditions. Kinetic profiles of the reactions were obtained by plotting the diffraction intensities of selected Bragg peaks vs. temperature. The extracted Temperature-Programmed-Reduction (TPR) diagrams were analyzed by appropriate kinetic models, leading to best results with the Avrami-Erofeev model for all reduction reactions considered. The activation energies for the two-step reduction of iron oxide were 65 and 37 kJmol⁻¹, respectively. The average value for the reduction of CoO to Co was found to be around 21 kJ mol⁻¹. Such results may contribute to develop efficient and inexpensive non-noble metal-based catalysts in element form, e.g., Fe, Co, via heterogenization of metal complexes on mesoporous supports.

Keywords: non-isothermal kinetics, carbon aerogel, in-situ synchrotron X-ray diffraction, reduction mechanisms

Procedia PDF Downloads 238
11562 Investigation on Unsteady Flow of a Turbine Stage with Negative Bowed Stator

Authors: Keke Gao, Tao Lin, Yonghui Xie, Di Zhang

Abstract:

Complicated unsteady flow in axial turbines produces high-frequency unsteady aerodynamic exciting force, which threatens the safe operation of turbines. This paper illustrates how negative-bowed stator reduces the rotor unsteady aerodynamic exciting force by unsteady flow field. With the support of three-dimensional viscous compressible Navier-Stokes equation, the single axial turbines with 0, -10 and -20 degree bowed stator are comparably investigated, aiming to identify the flow field structure difference caused by various negative-bowed degrees. The results show that negative-bowed stator strengthens the turbulence kinetic energy, which is further strengthened with the increase of negative-bowed degree. Meanwhile, the flow phenomenon including stator wakes and passage vortex is shown. In addition, the interaction of upstream negative-bowed wakes contributes to the reduction of unsteady blade load fluctuation. Furthermore, the aerodynamic exciting force decreases with the increasing negative bowed degree, while the efficiency is correspondingly reduced. This paper provides the reference for the alleviation of the harmful impact caused by unsteady interaction with the method of wake control.

Keywords: unsteady flow, axial turbine, wake, aerodynamic force, loss

Procedia PDF Downloads 294
11561 Influence of Cure Degree in GO and CNT-Epoxy Nanocomposites

Authors: Marina Borgert Moraes, Wesley Francisco, Filipe Vargas, Gilmar Patrocínio Thim

Abstract:

In recent years, carbon nanotubes (CNT) and graphene oxide (GO), especially the functionalized ones, have been added to epoxy resin in order to increase the mechanical, electrical and thermal properties of nanocomposites. However, it's still unknown how the presence of these nanoparticles influences the curing process and the final mechanical properties as well. In this work, kinetic and mechanical properties of the nanocomposites were analyzed, where the kinetic process was followed by DSC and the mechanical properties by DMA. Initially, CNT was annealed at high temperature (1800 °C) under vacuum atmosphere, followed by a chemical treatment using acids and ethylenediamine. GO was synthesized through chemical route, washed clean, dried and ground to #200. The presence of functional groups on CNT and GO surface was confirmed by XPS spectra and FT-IR. Then, epoxy resin, nanoparticles and acetone were mixed by sonication in order to obtain the composites. DSC analyses were performed on samples with different curing cycles (1h 80°C + 2h 120°C; 3h 80°C + 2h 120°C; 5h 80°C) and samples with different times at constant temperature (120°C). Results showed that the kinetic process and the mechanical strength are very dependent on the presence of graphene and functionalized-CNT in the nanocomposites.

Keywords: carbon nanotube, epoxy resin, Graphene oxide, nanocomposite

Procedia PDF Downloads 317
11560 Ix Operation for the Concentration of Low-Grade Uranium Leach Solution

Authors: Heba Ahmed Nawafleh

Abstract:

In this study, two commercial resins were evaluated to concentrate uranium from real solutions that were produced from analkaline leaching process of carbonate deposits. The adsorption was examined using a batch process. Different parameters were evaluated, including initial pH, contact time, temperature, adsorbent dose, and finally, uranium initial concentration. Both resins were effective and selective for uranium ions from the tested leaching solution. The adsorption isotherms data were well fitted for both resins using the Langmuir model. Thermodynamic functions (Gibbs free energy change ΔG, enthalpy change ΔH, and entropy change ΔS) were calculated for the adsorption of uranium. The result shows that the adsorption process is endothermic, spontaneous, and chemisorption processes took place for both resins. The kinetic studies showed that the equilibrium time for uranium ions is about two hours, where the maximum uptake levels were achieved. The kinetics studies were carried out for the adsorption of U ions, and the data was found to follow pseudo-second-order kinetics, which indicates that the adsorption of U ions was chemically controlled. In addition, the reusability (adsorption/ desorption) process was tested for both resins for five cycles, these adsorbents maintained removal efficiency close to first cycle efficiency of about 91% and 80%.

Keywords: uranium, adsorption, ion exchange, thermodynamic and kinetic studies

Procedia PDF Downloads 91
11559 Seasonal and Species Variations in Incidence of Foetal Loss at the Maiduguri Abattoir in Northern Nigeria

Authors: Abdulrazaq O. Raji, Abba Mohammed, Ibrahim D. Mohammed

Abstract:

This study was conducted to investigate foetal loss among slaughtered livestock species at the Maiduguri abattoir from 2009 to 2013. Record of animals slaughtered monthly and fetuses recovered were collected from the management of the Maiduguri abattoir. Data was subjected to Analysis of Variance using the General Linear Model of SPSS 13.0 with Season, Species and their interaction as fixed factors. Average yearly slaughter at the Maiduguri abattoir was 63,225 animals with cattle, camel, goat and sheep accounting for 19737, 7374, 19281 and 17540 of the total. The corresponding number of those pregnant were 3117, 839, 2281 and 2432 out of a total of 8522 animals. Thus, cattle, camel, goat and sheep accounted for 30.87, 11.53, 30.16 and 27.44%, respectively of the animals slaughtered at the Abattoir and 35.96, 9.68, 26.31 and 28.05% of the foetal loss. The effect of season and species on foetal loss was significant (P < 0.05). The number of pregnant animals slaughtered and foetal loss were higher during wet than dry season. Similarly, foetal loss at the abattoir was higher in the month of May in respect of camel, goat and sheep, and August for cattle. Camel was the least slaughtered animal and had the least number of pregnant females. Foetal loss (%) was higher (P < 0.05) for cattle compared to other species. The interaction showed that camel was the least slaughtered species in both seasons and cattle in the wet season had the highest foetal loss.

Keywords: abattoir, foetal loss, season, species

Procedia PDF Downloads 533
11558 Damage of Laminated Corrugated Sandwich Panels under Inclined Impact Loading

Authors: Muhammad Kamran, Xue Pu, Naveed Ahmed

Abstract:

Sandwich foam structures are efficient in impact energy absorption and making components lightweight; however their efficient use require a detailed understanding of its mechanical response. In this study, the foam core, laminated facings’ sandwich panel with internal triangular rib configuration is impacted by a spherical steel projectile at different angles using ABAQUS finite element package and damage mechanics is studied. Laminated ribs’ structure is sub-divided into three formations; all zeros, all 45 and optimized combination of zeros and 45 degrees. Impact velocity is varied from 250 m/s to 500 m/s with an increment of 50 m/s. The impact damage can significantly demolish the structural integrity and energy absorption due to fiber breakage, matrix cracking, and de-bonding. Macroscopic fracture study of the panel and core along with load-displacement responses and failure modes are the key parameters in the design of smart ballistic resistant structures. Ballistic impact characteristics of panels are studied on different speed, different inclination angles and its dependency on the base, and core materials, ribs formation, and cross-sectional spaces among them are determined. Impact momentum, penetration and kinetic energy absorption data and curves are compiled to predict the first and proximity impact in an effort to enhance the dynamic energy absorption.

Keywords: dynamic energy absorption, proximity impact, sandwich panels, impact momentum

Procedia PDF Downloads 387
11557 Determination of Steel Cleanliness of Non-Grain Oriented Electrical Steels

Authors: Emre Alan, Zafer Cetin

Abstract:

Electrical steels are widely used as a magnetic core materials in many electrical applications such as transformers, electric motors, and generators. Core loss property of these magnetic materials refers to dissipation of electrical energy during magnetization in service conditions. Therefore, in order to minimize the magnetic core loss, certain precautions are taken from steel producers; “Steel Cleanliness” is one of the major points among them. For obtaining lower core loss values, increasing proper elements in chemical composition such as silicon is a must. Therefore, impurities of these alloys are a key value for producing a cleaner steel. In this study, effects of impurity levels of different FeSi alloying materials to the steel cleanliness will be investigated. One of the important element content in FeSi alloy materials is Calcium. A SEM investigation will be done in order to present if Ca content in FeSi alloy is enough for proper inclusion modification or an additional Ca-treatment is required.

Keywords: electrical steels, FeSi alloy, impurities, steel cleanliness

Procedia PDF Downloads 333
11556 Soil Loss Assessment at Steep Slope: A Case Study at the Guthrie Corridor Expressway, Selangor, Malaysia

Authors: Rabiul Islam

Abstract:

The study was in order to assess soil erosion at plot scale Universal Soil Loss Equation (USLE) erosion model and Geographic Information System (GIS) technique have been used for the study 8 plots in Guthrie Corridor Expressway, Selangor, Malaysia. The USLE model estimates an average soil loss soil integrating several factors such as rainfall erosivity factor(R ), Soil erodibility factor (K), slope length and steepness factor (LS), vegetation cover factor as well as conservation practice factor (C &P) and Results shows that the four plots have very low rates of soil loss, i.e. NLDNM, NDNM, PLDM, and NDM having an average soil loss of 0.059, 0.106, 0.386 and 0.372 ton/ha/ year, respectively. The NBNM, PLDNM and NLDM plots had a relatively higher rate of soil loss, with an average of 0.678, 0.757 and 0.493ton/ha/year. Whereas, the NBM is one of the highest rate of soil loss from 0.842 ton/ha/year to maximum 16.466 ton/ha/year. The NBM plot was located at bare the land; hence the magnitude of C factor(C=0.15) was the highest one.

Keywords: USLE model, GIS, Guthrie Corridor Expressway (GCE), Malaysia

Procedia PDF Downloads 529
11555 Influence of an External Magnetic Field on the Acoustomagnetoelectric Field in a Rectangular Quantum Wire with an Infinite Potential by Using a Quantum Kinetic Equation

Authors: N. Q. Bau, N. V. Nghia

Abstract:

The acoustomagnetoelectric (AME) field in a rectangular quantum wire with an infinite potential (RQWIP) is calculated in the presence of an external magnetic field (EMF) by using the quantum kinetic equation for the distribution function of electrons system interacting with external phonons and electrons scattering with internal acoustic phonon in a RQWIP. We obtained ananalytic expression for the AME field in the RQWIP in the presence of the EMF. The dependence of AME field on the frequency of external acoustic wave, the temperature T of system, the cyclotron frequency of the EMF and the intensity of the EMF is obtained. Theoretical results for the AME field are numerically evaluated, plotted and discussed for a specific RQWIP GaAs/GaAsAl. This result has shown that the dependence of the AME field on intensity of the EMF is nonlinearly and it is many distinct maxima in the quantized magnetic region. We also compared received fields with those for normal bulk semiconductors, quantum well and quantum wire to show the difference. The influence of an EMF on AME field in a RQWIP is newly developed.

Keywords: rectangular quantum wire, acoustomagnetoelectric field, electron-phonon interaction, kinetic equation method

Procedia PDF Downloads 335
11554 Resilience among Children with and without Hearing Loss: A Comparative Study in Pakistan

Authors: Bushra Akram, Amina Tariq

Abstract:

Objective: This cross-sectional descriptive study aimed to compare the level of resilience among children with and without hearing loss. Methodology: In this descriptive cross sectional study total 500 children (with hearing loss = 250 and without hearing loss = 250) were recruited conveniently. Children with hearing loss were recruited from the special schools whereas children without hearing loss were selected from regular schools located in cities of Gujrat and Jhelum of Pakistan. Respondents’ age ranged from 9-14 years. Resiliency scale named RSCA (Resiliency Scales for children and adolescents) developed by Sandra Prince Embury (2006) was used. RSCA consist of three core theoretical areas: MAS (Sense of Mastery Scale), REL (Sense of Relatedness Scale) and REA (Emotional Reactivity Scale). Results: Findings indicated that there was a significant difference in the resilience level of participants with and without hearing loss. The mean comparison showed that the children with hearing loss showed lower scores on MAS (X̅ = 43.32, SD = 7.55) as well as on REL (X̅ = 49.96, SD = 7.65) as compared to their counterparts on MAS (X̅ = 53.96, SD = 9.90, t= -7.31***) and on REL (X̅ = 68.43, SD = 14.57,t= -10.18***). However children with hearing loss showed higher scores on REA (X̅ = 42.12, SD = 5.84) as compared to hearing participants (X̅ = 28.84, SD = 13.97, t = -8.20***). The findings revealed no significance difference in the resilience level of hearing and deaf children on the basis of their gender and age. Research Outcomes and Future Scope: Children with hearing loss showed a lower level of resilience, therefore, needs a program to develop resilience for better social-emotional adjustment and enhancement of their psychological well-being. In the end, the researcher gave recommendations for future research.

Keywords: children with hearing loss, psychological Wellbeing, resiliency scales for children and adolescents, resilience

Procedia PDF Downloads 182
11553 In-Situ Studies of Cyclohexane Oxidation Using Laser Raman Spectroscopy for the Refinement of Mechanism Based Kinetic Models

Authors: Christine Fräulin, Daniela Schurr, Hamed Shahidi Rad, Gerrit Waters, Günter Rinke, Roland Dittmeyer, Michael Nilles

Abstract:

The reaction mechanisms of many liquid-phase reactions in organic chemistry have not yet been sufficiently clarified. Process conditions of several hundred degrees celsius and pressures to ten megapascals complicate the sampling and the determination of kinetic data. Space resolved in-situ measurements promises new insights. A non-invasive in-situ measurement technique has the advantages that no sample preparation is necessary, there is no change in sample mixture before analysis and the sampling do no lead to interventions in the flow. Thus, the goal of our research was the development of a contact-free spatially resolved measurement technique for kinetic studies of liquid phase reaction under process conditions. Therefore we used laser Raman spectroscopy combined with an optical transparent microchannel reactor. To show the performance of the system we choose the oxidation of cyclohexane as sample reaction. Cyclohexane oxidation is an economically important process. The products are intermediates for caprolactam and adipic acid, which are starting materials for polyamide 6 and 6.6 production. To maintain high selectivities of 70 to 90 %, the reaction is performed in industry at a low conversion of about six percent. As Raman spectroscopy is usually very selective but not very sensitive the detection of the small product concentration in cyclohexane oxidation is quite challenging. To meet these requirements, an optical experimental setup was optimized to determine the concentrations by laser Raman spectroscopy with respect to good detection sensitivity. With this measurement technique space resolved kinetic studies of uncatalysed and homogeneous catalyzed cyclohexane oxidation were carried out to obtain details about the reaction mechanism.

Keywords: in-situ laser raman spectroscopy, space resolved kinetic measurements, homogeneous catalysis, chemistry

Procedia PDF Downloads 332
11552 Impact of Design Choices on the Life Cycle Energy of Modern Buildings

Authors: Mahsa Karimpour, Martin Belusko, Ke Xing, Frank Bruno

Abstract:

Traditionally the embodied energy of design choices which reduce operational energy were assumed to have a negligible impact on the life cycle energy of buildings. However with new buildings having considerably lower operational energy, the significance of embodied energy increases. A life cycle assessment of a population of house designs was conducted in a mild and mixed climate zone. It was determined not only that embodied energy dominates life cycle energy, but that the impact on embodied of design choices was of equal significance to the impact on operational energy.

Keywords: building life cycle energy, embodied energy, energy design measures, low energy buildings

Procedia PDF Downloads 770
11551 The Analysis of the Challenge China’s Energy Transition Faces and Proposed Solutions

Authors: Yuhang Wang

Abstract:

As energy is vital to industrial productivity and human existence, ensuring energy security becomes a critical government responsibility. The Chinese government has implemented the energy transition to safeguard China’s energy security. Throughout this progression, the Chinese government has faced numerous obstacles. This article seeks to describe the causes of China’s energy transition barriers and the steps taken by the Chinese government to overcome them.

Keywords: energy transition, energy market, fragmentation, path dependency

Procedia PDF Downloads 100
11550 Comprehensive Study of Renewable Energy Resources and Present Scenario in India

Authors: Aparna Bhat, Rajeshwari Hegde

Abstract:

Renewable energy sources also called non-conventional energy sources that are continuously replenished by natural processes. For example, solar energy, wind energy, bio-energy- bio-fuels grown sustain ably), hydropower etc., are some of the examples of renewable energy sources. A renewable energy system converts the energy found in sunlight, wind, falling-water, sea-waves, geothermal heat, or biomass into a form, we can use such as heat or electricity. Most of the renewable energy comes either directly or indirectly from sun and wind and can never be exhausted, and therefore they are called renewable. This paper presents a review about conventional and renewable energy scenario of India. The paper also presents current status, major achievements and future aspects of renewable energy in India and implementing renewable for the future is also been presented.

Keywords: solar energy, renewabe energy, wind energy, bio-diesel, biomass, feedin

Procedia PDF Downloads 610
11549 House Price Index Predicts a Larger Impact of Habitat Loss than Primary Productivity on the Biodiversity of North American Avian Communities

Authors: Marlen Acosta Alamo, Lisa Manne, Richard Veit

Abstract:

Habitat loss due to land use change is one of the leading causes of biodiversity loss worldwide. This form of habitat loss is a non-random phenomenon since the same environmental factors that make an area suitable for supporting high local biodiversity overlap with those that make it attractive for urban development. We aimed to compare the effect of two non-random habitat loss predictors on the richness, abundance, and rarity of nature-affiliated and human-affiliated North American breeding birds. For each group of birds, we simulated the non-random habitat loss using two predictors: the House Price Index as a measure of the attractiveness of an area for humans and the Normalized Difference Vegetation Index as a proxy for primary productivity. We compared the results of the two non-random simulation sets and one set of random habitat loss simulations using an analysis of variance and followed up with a Tukey-Kramer test when appropriate. The attractiveness of an area for humans predicted estimates of richness loss and increase of rarity higher than primary productivity and random habitat loss for nature-affiliated and human-affiliated birds. For example, at 50% of habitat loss, the attractiveness of an area for humans produced estimates of richness at least 5% lower and of a rarity at least 40% higher than primary productivity and random habitat loss for both groups of birds. Only for the species abundance of nature-affiliated birds, the attractiveness of an area for humans did not outperform primary productivity as a predictor of biodiversity following habitat loss. We demonstrated the value of the House Price Index, which can be used in conservation assessments as an index of the risks of habitat loss for natural communities. Thus, our results have relevant implications for sustainable urban land-use planning practices and can guide stakeholders and developers in their efforts to conserve local biodiversity.

Keywords: biodiversity loss, bird biodiversity, house price index, non-random habitat loss

Procedia PDF Downloads 86
11548 Numerical Investigation of the Bio-fouling Roughness Effect on Tidal Turbine

Authors: O. Afshar

Abstract:

Unlike other renewable energy sources, tidal current energy is an extremely reliable, predictable and continuous energy source as the current pattern and speed can be predicted throughout the year. A key concern associated with tidal turbines is their long-term reliability when operating in the hostile marine environment. Bio-fouling changes the physical shape and roughness of turbine components, hence altering the overall turbine performance. This paper seeks to employ Computational Fluid Dynamics (CFD) method to quantify the effects of this problem based on the obtained flow field information. The simulation is carried out on a NACA 63-618 aerofoil. The Reynolds Averaged Navier-Stokes (RANS) equations with Shear Stress Transport (SST) turbulent model are used to simulate the flow around the model. Different levels of fouling are studied on 2D aerofoil surface with quantified fouling height and density. In terms of lift and drag coefficient results, numerical results show good agreement with the experiment which was carried out in wind tunnel. Numerical results of research indicate that an increase in fouling thickness causes an increase in drag coefficient and a reduction in lift coefficient. Moreover, pressure gradient gradually becomes adverse as height of fouling increases. In addition, result by turbulent kinetic energy contour reveals it increases with fouling height and it extends into wake due to flow separation.

Keywords: tidal energy, lift coefficient, drag coefficient, roughness

Procedia PDF Downloads 382
11547 Effect of Non-Invasive Electrical Stimulation on Partial Hearing Loss: Pilot Study

Authors: Geetanjali Saggar

Abstract:

Background: Partial hearing loss is the inability to hear effectively as a normal hearing individual whose hearing threshold is 20 dB or better in both ears. Individuals with partial hearing loss may benefit from non-invasive electrical stimulation as a method of therapy and possible intervention. Objective: The project aims to assess and relate the efficacy of electrical stimulation on individuals with partial hearing loss. The study's goal was to evaluate the different sorts of non-invasive electrical stimulation in tinnitus and hearing loss in order to build the framework for future research. Method: In this pilot study, a total of five patients of age group above 50 years were selected with partial hearing loss. The electrical modality of Repetitive Transcranial Magnetic Stimulation (RTMS) was used among the patients and was evaluated using gold questionnaires- HHIA and APHAB for hearing at intervals of 0-7-14 days. The statistical data was analyzed by SPSS software-16. Results: There were not much significant changes in the hearing of the patients when non-invasive electrical modality was applied as an intervention in the partial hearing loss condition. However, there was minimal change in the daily functioning of the patient with the application of intervention. Conclusion: This study concluded that non-invasive electrical stimulation had minimal to no effect on the partial hearing of the patients.

Keywords: non-invasive, hearing loss, transcranial magnetic stimulation, partial deafness, transcranial direct current stimulation, tinnitus

Procedia PDF Downloads 11
11546 Major Gullies Erosion Sites and Volume of Soil Loss in Edo State, Nigeria

Authors: Augustine Osayande

Abstract:

This research is on Major Gullies Erosion Sites and Volume of Soil Loss in Edo State, Nigeria. The primary objective was to identify notable gullies sites and quantify the volume of soil loss in the study area. Direct field observation and measurement of gullies dimensions was done with the help of research assistants using a measuring tape, Camera and 3percent accuracy Global Positioning System (GPS). The result revealed that notable gullies in the area have resulted in the loss of lives and properties, destruction of arable lands and wastage of large areas of usable lands. Gullies in Edo North have Mean Volume of Soil Loss of 614, 763.33 m³, followed by Edo South with 79,604.76 m³ and Edo Central is 46,242.98 m³ and as such an average of 1,772, 888.7m3 of soil is lost annually in the study area due to gully erosion problem. The danger of gully erosion in helpless regions like Edo State called for urgent remedies in order to arrest the further loss of soil, buildings and other properties.

Keywords: Edo, magnitude, gully, volume, soil, sloss

Procedia PDF Downloads 141
11545 Dynamic Modeling of Advanced Wastewater Treatment Plants Using BioWin

Authors: Komal Rathore, Aydin Sunol, Gita Iranipour, Luke Mulford

Abstract:

Advanced wastewater treatment plants have complex biological kinetics, time variant influent flow rates and long processing times. Due to these factors, the modeling and operational control of advanced wastewater treatment plants become complicated. However, development of a robust model for advanced wastewater treatment plants has become necessary in order to increase the efficiency of the plants, reduce energy costs and meet the discharge limits set by the government. A dynamic model was designed using the Envirosim (Canada) platform software called BioWin for several wastewater treatment plants in Hillsborough County, Florida. Proper control strategies for various parameters such as mixed liquor suspended solids, recycle activated sludge and waste activated sludge were developed for models to match the plant performance. The models were tuned using both the influent and effluent data from the plant and their laboratories. The plant SCADA was used to predict the influent wastewater rates and concentration profiles as a function of time. The kinetic parameters were tuned based on sensitivity analysis and trial and error methods. The dynamic models were validated by using experimental data for influent and effluent parameters. The dissolved oxygen measurements were taken to validate the model by coupling them with Computational Fluid Dynamics (CFD) models. The Biowin models were able to exactly mimic the plant performance and predict effluent behavior for extended periods. The models are useful for plant engineers and operators as they can take decisions beforehand by predicting the plant performance with the use of BioWin models. One of the important findings from the model was the effects of recycle and wastage ratios on the mixed liquor suspended solids. The model was also useful in determining the significant kinetic parameters for biological wastewater treatment systems.

Keywords: BioWin, kinetic modeling, flowsheet simulation, dynamic modeling

Procedia PDF Downloads 153
11544 A Low Insertion Loss Variation 10-35 GHz Phase Shifter

Authors: Soroush Rasti Boroujeni, S. Hassan Mousavi, Javad Ebrahimizadeh, Ardeshir Palizban, Mohammad-Reza Nezhad-Ahmadi, Safieddin Safavi-Naeini

Abstract:

This paper presents a wideband True Time Delay (TTD) phase shifter with low insertion loss variation. The circuit benefits from a controllable resistive load shunt with transmission line segments to optimize return loss variations, addressing the unbalanced capacitive nature of the varactor. The phase shifter reduces the complexity of the calibration process because the dependency of insertion loss on voltage controls is improved up to 3 dB. The TTD phase shifter provides a continuous changing delay time of 6.4 ps with low insertion loss (IL) in the 10-35 GHz frequency range. The proposed circuit benefits from lowloss phase shifters with a small footprint. Fabricated using a 65 nm CMOC process, the TTD phase shifter occupies only 388 × 615 µm 2 of chip area, achieving a 20% improvements compared to conventional TTD phase shifters.

Keywords: millimeter-wave phased-array, true time delay phase shifter, insertion loss variation, compact size

Procedia PDF Downloads 7
11543 Innovative Pump Design Using the Concept of Viscous Fluid Sinusoidal Excitation

Authors: Ahmed H. Elkholy

Abstract:

The concept of applying a prescribed oscillation to viscous fluids to aid or increase flow is used to produce a maintenance free pump. Application of this technique to fluids presents unique problems such as physical separation; control of heat and mass transfer in certain industrial applications; and improvement of some fluid process methods. The problem as stated is to obtain the velocity distribution, wall shear stress and energy expended when a pipe containing a stagnant viscous fluid is externally excited by a sinusoidal pulse, one end of the pipe being pinned. On the other hand, the effect of different parameters on the results are presented. Such parameters include fluid viscosity, frequency of oscillations and pipe geometry. It was found that the flow velocity through the pump is maximum at the pipe wall, and it decreases rapidly towards the pipe centerline. The frequency of oscillation should be above a certain value in order to obtain meaningful flow velocity. The amount of energy absorbed in the system is mainly due to pipe wall strain energy, while the fluid pressure and kinetic energies are comparatively small.

Keywords: sinusoidal excitation, pump, shear stress, flow

Procedia PDF Downloads 314
11542 Using Nonhomogeneous Poisson Process with Compound Distribution to Price Catastrophe Options

Authors: Rong-Tsorng Wang

Abstract:

In this paper, we derive a pricing formula for catastrophe equity put options (or CatEPut) with non-homogeneous loss and approximated compound distributions. We assume that the loss claims arrival process is a nonhomogeneous Poisson process (NHPP) representing the clustering occurrences of loss claims, the size of loss claims is a sequence of independent and identically distributed random variables, and the accumulated loss distribution forms a compound distribution and is approximated by a heavy-tailed distribution. A numerical example is given to calibrate parameters, and we discuss how the value of CatEPut is affected by the changes of parameters in the pricing model we provided.

Keywords: catastrophe equity put options, compound distributions, nonhomogeneous Poisson process, pricing model

Procedia PDF Downloads 167
11541 Economic Analysis of Policy Instruments for Energy Efficiency

Authors: Etidel Labidi

Abstract:

Energy efficiency improvement is one of the means to reduce energy consumption and carbon emissions. Recently, some developed countries have implemented the tradable white certificate scheme (TWC) as a new policy instrument based on market approach to support energy efficiency improvements. The major focus of this paper is to compare the White Certificates (TWC) scheme as an innovative policy instrument for energy efficiency improvement to other policy instruments: energy taxes and regulations setting a minimum level of energy efficiency. On the basis of our theoretical discussion and numerical simulation, we show that the white certificates system is the most interesting policy instrument for saving energy because it generates the most important level of energy savings and the least increase in energy service price.

Keywords: energy savings, energy efficiency, energy policy, white certificates

Procedia PDF Downloads 334
11540 Application of PV/Wind-Based Green Energy to Power Cellular Base Station

Authors: Francis Okodede, Edafe Lucky Okotie

Abstract:

Conventional energy sources based on oil, coal, and natural gas has posed a trait to environment and to human health. Green energy stands as an alternative because it has proved to be eco-friendly. The prospective of renewable energy sources are quite vast as they can, in principle, meet many times the world’s energy demand. Renewable energy sources, such as wind and solar, can provide sustainable energy services based on the use of routinely available indigenous resources. New renewable energy sources (solar energy, wind energy, and modern bio-energy) are currently contributing immensely to global energy demand. A number of studies have shown the potential and contribution of renewable energy to global energy supplies, indicating that in the second half of the 21st century, it is going to be a major source and driver in the telecommunication sector. Green energy contribution might reach as much as 50 percent of global energy demands if the right policies are in place. This work suggests viable non-conventional means of energy supply to power a cellular base station.

Keywords: base station, energy storage, green energy, rotor efficiency, solar energy, wind energy

Procedia PDF Downloads 96
11539 The Classification of Parkinson Tremor and Essential Tremor Based on Frequency Alteration of Different Activities

Authors: Chusak Thanawattano, Roongroj Bhidayasiri

Abstract:

This paper proposes a novel feature set utilized for classifying the Parkinson tremor and essential tremor. Ten ET and ten PD subjects are asked to perform kinetic, postural and resting tests. The empirical mode decomposition (EMD) is used to decompose collected tremor signal to a set of intrinsic mode functions (IMF). The IMFs are used for reconstructing representative signals. The feature set is composed of peak frequencies of IMFs and reconstructed signals. Hypothesize that the dominant frequency components of subjects with PD and ET change in different directions for different tests, difference of peak frequencies of IMFs and reconstructed signals of pairwise based tests (kinetic-resting, kinetic-postural and postural-resting) are considered as potential features. Sets of features are used to train and test by classifier including the quadratic discriminant classifier (QLC) and the support vector machine (SVM). The best accuracy, the best sensitivity and the best specificity are 90%, 87.5%, and 92.86%, respectively.

Keywords: tremor, Parkinson, essential tremor, empirical mode decomposition, quadratic discriminant, support vector machine, peak frequency, auto-regressive, spectrum estimation

Procedia PDF Downloads 442
11538 Raising Awareness to Health Professionals about Emotional Needs of Families Suffering Perinatal Loss through a Short Documentary

Authors: Elisenda Camprecios, Alicia Macarrila, Montse Albiol, Neus Garriga Garriga

Abstract:

The loss of a child during pregnancy, or shortly after birth, is not a common occurrence, but it is a prevalent fact in our society. When this loss happens, life and death walk together. The grief that parents experience following a perinatal loss is a devastating experience. Professionals are aware that the quality of care offered during this first period is crucial to support the families experiencing a perinatal loss and meet their needs. However, it is not always easy for the health care professionals to know what to say and what to do in these difficult circumstances. Given the complexity of the Health, painful process that a family must face when is affected by such loss, we believe that the creation of a protocol that pays special attention to the emotional needs of those couples can be a very valuable tool for the professionals. The short documentary named ‘When the illusion vanished’ was created as part of the material of this protocol, which focuses on the emotional needs of the families who have suffered a perinatal loss. This video is designed to see what impact has a perinatal death and to raise awareness among professionals working in this field. The methodology is based on interviews with couples who have experienced perinatal death and to professionals who accompany families suffering from perinatal loss. The use of sensitive and empathized words, being encouraged to express feelings, respect the time, appropriate training for the professionals are some of the issues reflected in this documentary. We believe that this video has contributed to help health care professionals to empathize and understand the need to be able to accompany these families with the appropriate care, respectful, empathetic attitude and professionalism so that they can start the path to a ‘healthy’ mourning.

Keywords: neonatal loss, midwifery, perinatal bereavement, perinatal loss

Procedia PDF Downloads 150
11537 The Act of Care: Reimagined Rituals towards Unattachment

Authors: Ioana G. Turcan

Abstract:

reimagined rituals towards unattachment wants to look at an ambiguous loss through the perspective of caregivers, those that accompany us at the beginning and possibly the end of life, those that observe, accumulate, and are impacted by our behavior and needs, but also those that are the witnesses of the human vulnerability. Someone taking care of a patient with dementia experiences ambiguous loss, being in a present of a person partially present, partially absent. The one offering care needs care, not isolation and the aim of the project is to consolidate existing communities or engage other possible ones using performance, storytelling, and other artistic methods. The long-term aim is that with community work, we will manage to co-create rituals in order to help us live with this kind of loss. Looking at them through the lens of different cultures and individuals exercises both the ability to extract the universal essence of a ritual, but also the need and freedom to express the specificity of each situation. To be seen and acknowledged by others, but more importantly, to see oneself from outside with dignity, is very powerful. Oftentimes we forget to express, look and appreciate our own stories, and instead, we choose to outcast them.

Keywords: grief, socio-politics of loss, ambiguous loss, rituals

Procedia PDF Downloads 177