Search results for: service lifetime
4027 Lifetime Improvement of IEEE.802.15.6 Sensors in Scheduled Access Mode
Authors: Latif Adnane, C. E. Ait Zaouiat, M. Eddabbah
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In Wireless Body Area Networks, the issue of systems lifetime is a big challenge to complete. In this paper, we have tackled this subject to suggest some solutions. For this aim, we have studied some batteries characteristics related to human body temperature. Moreover, we have analyzed a mathematical model which defines sensors lifetime (battery lifetime). Based on this model, we note that the random access increases the energy consumption, because nodes are waking up during the whole superframe period. Results show that using scheduled mode access of IEEE 802.15.6 maximizes the lifetime function, by setting nodes in the sleep mode in the inactive period of transmission.Keywords: battery, energy consumption, IEEE 802.15.6, lifetime, polling
Procedia PDF Downloads 3364026 Economical Transformer Selection Implementing Service Lifetime Cost
Authors: Bonginkosi A. Thango, Jacobus A. Jordaan, Agha F. Nnachi
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In this day and age, there is a proliferate concern from all governments across the globe to barricade the environment from greenhouse gases, which absorb infrared radiation. As a result, solar photovoltaic (PV) electricity has been an expeditiously growing renewable energy source and will eventually undertake a prominent role in the global energy generation. The selection and purchasing of energy-efficient transformers that meet the operational requirements of the solar photovoltaic energy generation plants then become a part of the Independent Power Producers (IPP’s) investment plan of action. Taking these into account, this paper proposes a procedure that put into effect the intricate financial analysis necessitated to precisely evaluate the transformer service lifetime no-load and load loss factors. This procedure correctly set forth the transformer service lifetime loss factors as a result of a solar PV plant’s sporadic generation profile and related levelized costs of electricity into the computation of the transformer’s total ownership cost. The results are then critically compared with the conventional transformer total ownership cost unaccompanied by the emission costs, and demonstrate the significance of the sporadic energy generation nature of the solar PV plant on the total ownership cost. The findings indicate that the latter play a crucial role for developers and Independent Power Producers (IPP’s) in making the purchase decision during a tender bid where competing offers from different transformer manufactures are evaluated. Additionally, the susceptibility analysis of different factors engrossed in the transformer service lifetime cost is carried out; factors including the levelized cost of electricity, solar PV plant’s generation modes, and the loading profile are examined.Keywords: solar photovoltaic plant, transformer, total ownership cost, loss factors
Procedia PDF Downloads 1204025 Useful Lifetime Prediction of Rail Pads for High Speed Trains
Authors: Chang Su Woo, Hyun Sung Park
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Useful lifetime evaluations of rail-pads were very important in design procedure to assure the safety and reliability. It is, therefore, necessary to establish a suitable criterion for the replacement period of rail pads. In this study, we performed properties and accelerated heat aging tests of rail pads considering degradation factors and all environmental conditions including operation, and then derived a lifetime prediction equation according to changes in hardness, thickness, and static spring constants in the Arrhenius plot to establish how to estimate the aging of rail pads. With the useful lifetime prediction equation, the lifetime of e-clip pads was 2.5 years when the change in hardness was 10% at 25°C; and that of f-clip pads was 1.7 years. When the change in thickness was 10%, the lifetime of e-clip pads and f-clip pads is 2.6 years respectively. The results obtained in this study to estimate the useful lifetime of rail pads for high speed trains can be used for determining the maintenance and replacement schedule for rail pads.Keywords: rail pads, accelerated test, Arrhenius plot, useful lifetime prediction, mechanical engineering design
Procedia PDF Downloads 3164024 Exploring Structure of Human Chromosomes Using Fluorescence Lifetime Imaging
Authors: A. Bhartiya, S. Botchway, M. Yusuf, I. Robinson
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Chromatin condensation is maintained by DNA-based proteins and some divalent cations (Mg²⁺, Ca²⁺, etc.). Condensation process during cell division maintains structural and functional organizations of chromosomes by transferring genetic information correctly to daughter cells. Fluorescence Lifetime Imaging (FLIM) technique measures the fluorescence decay of fixed human chromosomes by calculating the lifetime of fluorophores at a pixel x of the arrival of each photon as a function of time delay t, following excitation with a laser pulse. Fixed metaphase human chromosomes were labelled with DNA-binding dye, DAPI and later DAPI fluorescence lifetime measured using multiphoton microscopy. 5 out of 23 pairs of human chromosomes shown shorter lifetime at the centromere region, differentiating proportion of compaction along the length of chromosomes. Different lifetime was observed in a condensed and de-condensed chromosome. It clearly indicates the involvement of divalent cations in the process of condensation.Keywords: divalent cations, FLIM (Fluorescence Lifetime Imaging), human chromosomes, multiphoton microscopy
Procedia PDF Downloads 2804023 Useful Lifetime Prediction of Chevron Rubber Spring for Railway Vehicle
Authors: Chang Su Woo, Hyun Sung Park
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Useful lifetime evaluation of chevron rubber spring was very important in design procedure to assure the safety and reliability. It is, therefore, necessary to establish a suitable criterion for the replacement period of chevron rubber spring. In this study, we performed characteristic analysis and useful lifetime prediction of chevron rubber spring. Rubber material coefficient was obtained by curve fittings of uni-axial tension, equi bi-axial tension and pure shear test. Computer simulation was executed to predict and evaluate the load capacity and stiffness for chevron rubber spring. In order to useful lifetime prediction of rubber material, we carried out the compression set with heat aging test in an oven at the temperature ranging from 50°C to 100°C during a period 180 days. By using the Arrhenius plot, several useful lifetime prediction equations for rubber material was proposed.Keywords: chevron rubber spring, material coefficient, finite element analysis, useful lifetime prediction
Procedia PDF Downloads 5624022 Lifetime Assessment of Highly Efficient Metal-Based Air-Diffuser through Accelerated Degradation Test
Authors: Jinyoung Choi, Tae-Ho Yoon, Sunmook Lee
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Degradation of standard oxygen transfer efficiency (SOTE) with time was observed for the assessment of lifetime of metal-based air-diffuser, which displaced a polymer composite-based air-diffuser in order to attain a longer lifetime in the actual field. The degradation of air-diffuser occurred due to the failure of the formation of small and uniform air bubbles since the patterns formed on the disc of air-diffuser deteriorated and/or changed from their initial shapes while they were continuously exposed to the air blowing condition during the operation in the field. Therefore, the lifetime assessment of metal-based air-diffuser was carried out through an accelerated degradation test by accelerating the air-blowing conditions in 200 L/min, 300 L/min, and 400 L/min and the lifetime of normal operating condition at 120 L/min was predicted. It was found that Weibull distribution was the most proper one for describing the lifetime distribution of metal-based air-diffuser in the present study. The shape and scale parameters indicated that the accelerated blowing conditions were all within the acceleration domain. The lifetime was predicted by adopting inverse power model for a stress-life relationship and estimated to be B10=94,004 hrs with CL=95%. Acknowledgement: This work was financially supported by the Ministry of Trade, Industry and Energy (Grant number: N0001475).Keywords: accelerated degradation test, air-diffuser, lifetime assessment, SOTE
Procedia PDF Downloads 5584021 Residual Lifetime Estimation for Weibull Distribution by Fusing Expert Judgements and Censored Data
Authors: Xiang Jia, Zhijun Cheng
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The residual lifetime of a product is the operation time between the current time and the time point when the failure happens. The residual lifetime estimation is rather important in reliability analysis. To predict the residual lifetime, it is necessary to assume or verify a particular distribution that the lifetime of the product follows. And the two-parameter Weibull distribution is frequently adopted to describe the lifetime in reliability engineering. Due to the time constraint and cost reduction, a life testing experiment is usually terminated before all the units have failed. Then the censored data is usually collected. In addition, other information could also be obtained for reliability analysis. The expert judgements are considered as it is common that the experts could present some useful information concerning the reliability. Therefore, the residual lifetime is estimated for Weibull distribution by fusing the censored data and expert judgements in this paper. First, the closed-forms concerning the point estimate and confidence interval for the residual lifetime under the Weibull distribution are both presented. Next, the expert judgements are regarded as the prior information and how to determine the prior distribution of Weibull parameters is developed. For completeness, the cases that there is only one, and there are more than two expert judgements are both focused on. Further, the posterior distribution of Weibull parameters is derived. Considering that it is difficult to derive the posterior distribution of residual lifetime, a sample-based method is proposed to generate the posterior samples of Weibull parameters based on the Monte Carlo Markov Chain (MCMC) method. And these samples are used to obtain the Bayes estimation and credible interval for the residual lifetime. Finally, an illustrative example is discussed to show the application. It demonstrates that the proposed method is rather simple, satisfactory, and robust.Keywords: expert judgements, information fusion, residual lifetime, Weibull distribution
Procedia PDF Downloads 1374020 Evaluation of E-Government Service Quality
Authors: Nguyen Manh Hien
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Service quality is the highest requirement from users, especially for the service in electronic government. During the past decades, it has become a major area of academic investigation. Considering this issue, there are many researches that evaluated the dimensions and e-service contexts. This study also identified the dimensions of service quality but focused on a new conceptual and provides a new methodological in developing measurement scales of e-service quality such as information quality, service quality and organization quality. Finally, the study will suggest a key factor to evaluate e-government service quality better.Keywords: dimensionality, e-government, e-service, e-service quality
Procedia PDF Downloads 5344019 Power Management in Wireless Combustible Gas Sensors
Authors: Denis Spirjakin, Alexander Baranov, Saba Akbari, Natalia Kalenova, Vladimir Sleptsov
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In this paper we propose the approach to power management in wireless combustible gas sensors. This approach makes possible drastically prolong sensor nodes autonomous lifetime. That is necessary to tie battery replacement to every year technical service procedures which are claimed by safety standards. Using this approach the current consumption of the wireless combustible gas sensor node was decreased from 80 mA to less than 2 mA and the power consumption from more than 220 mW to 4.6 mW. These values provide autonomous lifetime of the node more than one year.Keywords: Gas sensors, power management, wireless sensor network
Procedia PDF Downloads 7184018 The Effect of Chemical Degradation of a Nonwoven Filter Media Membrane in Polyester
Authors: Rachid El Aidani, Phuong Nguyen-Tri, Toan Vu-Khanh
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The filter media in synthetic fibre is the most geotextile materials used in aerosol and drainage filtration, particularly for buildings soil reinforcement in civil engineering due to its appropriated properties and its low cost. However, the current understanding of the durability and stability of this material in real service conditions, especially under severe long-term conditions are completely limited. This study has examined the effects of the chemical aging of a filter media in polyester non-woven under different temperatures (50, 70 and 80˚C) and pH (2. 7 and 12). The effect of aging conditions on mechanical properties, morphology, permeability, thermal stability and molar weigh changes is investigated. The results showed a significant reduction of mechanical properties in term of tensile strength, puncture force and tearing forces of the filter media after chemical aging due to the chemical degradation. The molar mass and mechanical properties changes in different temperature and pH showed a complex dependence of material properties on environmental conditions. The SEM and AFM characterizations showed a significant impact of the thermal aging on the morphological properties of the fibers. Based on the obtained results, the lifetime of the material in different temperatures was determined by the use of the Arrhenius model. These results provide useful information to better understand phenomena occurring during chemical aging of the filter media and may help to predict the service lifetime of this material in real used conditions.Keywords: nonwoven membrane, chemical aging, mechanical properties, lifetime, filter media
Procedia PDF Downloads 3124017 Chemical Degradation of a Polyester Nonwoven Membrane Used in Aerosol and Drainage Filter
Authors: Rachid El Aidani, Phuong Nguyen-Tri, Toan Vu-Khanh
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The filter media in synthetic fibre is the most geotextile materials used in aerosol and drainage filtration, particularly for buildings soil reinforcement in civil engineering due to its appropriated properties and its low cost. However, the current understanding of the durability and stability of this material in real service conditions, especially under severe long-term conditions are completely limited. This study has examined the effects of the chemical aging of a filter media in polyester nonwoven under different temperatures (50, 70 and 80˚C) and pH (2. 7 and 12). The effect of aging conditions on mechanical properties, morphology, permeability, thermal stability and molar weigh changes is investigated. The results showed a significant reduction of mechanical properties in term of tensile strength, puncture force and tearing forces of the filter media after chemical aging due to the chemical degradation. The molar mass and mechanical properties changes in different temperature and pH showed a complex dependence of material properties on environmental conditions. The SEM and AFM characterizations showed a significant impact of the thermal aging on the morphological properties of the fibres. Based on the obtained results, the lifetime of the material in different temperatures was determined by the use of the Arrhenius model. These results provide useful information to better understand phenomena occurring during chemical aging of the filter media and may help to predict the service lifetime of this material in real used conditions.Keywords: nonwoven membrane, chemical aging, mechanical properties, lifetime, filter media
Procedia PDF Downloads 3434016 X-Ray Diffraction Technique as a Means for Degradation Assessment of Welded Joints
Authors: Jaroslav Fiala, Jaroslav Kaiser, Pavel Zlabek, Vaclav Mentl
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The X-ray diffraction technique was recognized as a useful tool for the assessment of material degradation degree after a long-time service. In many industrial applications materials are subjected to degradation of mechanical properties as a result of real service conditions. The assessment of the remnant lifetime of components and structures is commonly based on correlated procedures including numerous destructive, non-destructive and mathematical techniques that should guarantee reasonable precise assessment of the current damage extent of materials in question and the remnant lifetime assessment. This paper summarizes results of an experimental programme concentrated on mechanical properties degradation of welded components. Steel an Al-alloy test specimens of base metal, containing welds and simple weldments were fatigue loaded at room temperature to obtain Woehler S-N curve. X-ray diffraction technique was applied to assess the degradation degree of material as a result of cyclic loading.Keywords: fatigue loading, material degradation, steels, AL-alloys, X-ray diffraction
Procedia PDF Downloads 4334015 Computing Customer Lifetime Value in E-Commerce Websites with Regard to Returned Orders and Payment Method
Authors: Morteza Giti
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As online shopping is becoming increasingly popular, computing customer lifetime value for better knowing the customers is also gaining more importance. Two distinct factors that can affect the value of a customer in the context of online shopping is the number of returned orders and payment method. Returned orders are those which have been shipped but not collected by the customer and are returned to the store. Payment method refers to the way that customers choose to pay for the price of the order which are usually two: Pre-pay and Cash-on-delivery. In this paper, a novel model called RFMSP is presented to calculated the customer lifetime value, taking these two parameters into account. The RFMSP model is based on the common RFM model while adding two extra parameter. The S represents the order status and the P indicates the payment method. As a case study for this model, the purchase history of customers in an online shop is used to compute the customer lifetime value over a period of twenty months.Keywords: RFMSP model, AHP, customer lifetime value, k-means clustering, e-commerce
Procedia PDF Downloads 3114014 Testing of Small Local Zones by Means of Small Punch Test at Room and Creep Temperatures
Authors: Vaclav Mentl, Josef Volak
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In many industrial applications, materials are subjected to degradation of mechanical properties as a result of real service conditions, temperature, cyclic loading, humidity or other corrosive media, irradiation, their combination etc. The assessment of the remaining lifetime of components and structures is commonly based on correlated procedures including numerous destructive, non-destructive and mathematical techniques that should guarantee reasonably precise assessment of the current damage extent of materials in question and the remaining lifetime evaluation of the component under consideration. The answers to demands of customers to extend the lifetime of existing components beyond their original design life must be based on detailed assessment of the current degradation extent, what can be rarely realised by means of traditional mechanical (standardised) tests that need relatively large volumes of representative material for the test specimen manufacturing. This fact accelerated the research of miniaturised test specimen that can be sampled non-invasively from the component.Keywords: small punch test, correlation, creep, mechanical properties
Procedia PDF Downloads 2724013 Adoption of Lean Thinking and Service Improvement for Care Home Service
Authors: Chuang-Chun Chiou
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Ageing population is a global trend; therefore the need of care service has been increasing dramatically. There are three basic forms of service delivered to the elderly: institution, community, and home. Particularly, the institutional service can be seen as an extension of medical service. The nursing home or so-called care home which is equipped with professional staff and facilities can provide a variety of service including rehabilitation service, short-term care, and long term care. Similar to hospital and other health care service, care home service do need to provide quality and cost-effective service to satisfy the dwellers. The main purpose of this paper is to show how lean thinking and service innovation can be applied to care home operation. The issues and key factors of implementing lean practice are discussed.Keywords: lean, service improvement, SERVQUAL, care home service
Procedia PDF Downloads 6024012 Analyzing the Shearing-Layer Concept Applied to Urban Green System
Authors: S. Pushkar, O. Verbitsky
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Currently, green rating systems are mainly utilized for correctly sizing mechanical and electrical systems, which have short lifetime expectancies. In these systems, passive solar and bio-climatic architecture, which have long lifetime expectancies, are neglected. Urban rating systems consider buildings and services in addition to neighborhoods and public transportation as integral parts of the built environment. The main goal of this study was to develop a more consistent point allocation system for urban building standards by using six different lifetime shearing layers: Site, Structure, Skin, Services, Space, and Stuff, each reflecting distinct environmental damages. This shearing-layer concept was applied to internationally well-known rating systems: Leadership in Energy and Environmental Design (LEED) for Neighborhood Development, BRE Environmental Assessment Method (BREEAM) for Communities, and Comprehensive Assessment System for Building Environmental Efficiency (CASBEE) for Urban Development. The results showed that LEED for Neighborhood Development and BREEAM for Communities focused on long-lifetime-expectancy building designs, whereas CASBEE for Urban Development gave equal importance to the Building and Service Layers. Moreover, although this rating system was applied using a building-scale assessment, “Urban Area + Buildings” focuses on a short-lifetime-expectancy system design, neglecting to improve the architectural design by considering bio-climatic and passive solar aspects.Keywords: green rating system, urban community, sustainable design, standardization, shearing-layer concept, passive solar architecture
Procedia PDF Downloads 5734011 The Effect of Proper Drainage on the Cost of Building and Repairing Roads
Authors: Seyed Abbas Tabatabaei, Saeid Amini, Hamid Reza Ghafouri
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One of the most important factors in flexible pavement failure is the lack of proper drainage along the roads. Water on the Paving Systems is one of the main parameters of pavement failure. Though, if water is discharged without delay and prior to discharge in order to prevent damaging the pavement the lifetime of the pavement will be considerably increased. In this study, duration of water stay and materials properties in pavement systems and the effects of aggregate gradation, and hydraulic conductivity of the drainage rate and Effects of subsurface drainage systems, drainage and reduction in the lifetime of the pavement have been studied. The study conducted in accordance with the terms offered can be concluded as under. The more hydraulic conductivity the less drainage time and the use of sub-surface drainage system causes two to three times of the pavement lifetime. In this research it has been tried by study and calculate the drained and undrained pavements lifetime by considering the effectiveness of water and drainage coefficient on flexible materials modulus and by using KENLAYER software to compare the present value cost of these pavements has been paid for a 20 year lifetime design. In this study, 14 pavement sections have been considered, of which 7 sections have been drained and 7 other not. Results show that drained pavements have more initial costs but the failure severity is so little in them and have longer lifetime for a 20 year lifetime design, the drained pavements seem so economic.Keywords: drainage, base and sub-base, elasticity modulus, aggregation
Procedia PDF Downloads 3624010 Design of Cloud Service Brokerage System Intermediating Integrated Services in Multiple Cloud Environment
Authors: Dongjae Kang, Sokho Son, Jinmee Kim
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Cloud service brokering is a new service paradigm that provides interoperability and portability of application across multiple Cloud providers. In this paper, we designed cloud service brokerage system, any broker, supporting integrated service provisioning and SLA based service life cycle management. For the system design, we introduce the system concept and whole architecture, details of main components and use cases of primary operations in the system. These features ease the Cloud service provider and customer’s concern and support new Cloud service open market to increase cloud service profit and prompt Cloud service echo system in cloud computing related area.Keywords: cloud service brokerage, multiple Clouds, Integrated service provisioning, SLA, network service
Procedia PDF Downloads 4794009 A Lifetime-Enhancing Monitoring Node Distribution Using Minimum Spanning Tree in Mobile Ad Hoc Networks
Authors: Sungchul Ha, Hyunwoo Kim
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In mobile ad hoc networks, all nodes in a network only have limited resources and calculation ability. Therefore communication topology which have long lifetime is good for all nodes in mobile ad hoc networks. There are a variety of researches on security problems in wireless ad hoc networks. The existing many researches try to make efficient security schemes to reduce network power consumption and enhance network lifetime. Because a new node can join the network at any time, the wireless ad hoc networks are exposed to various threats and can be destroyed by attacks. Resource consumption is absolutely necessary to secure networks, but more resource consumption can be a critical problem to network lifetime. This paper focuses on efficient monitoring node distribution to enhance network lifetime in wireless ad hoc networks. Since the wireless ad hoc networks cannot use centralized infrastructure and security systems of wired networks, a new special IDS scheme is necessary. The scheme should not only cover all nodes in a network but also enhance the network lifetime. In this paper, we propose an efficient IDS node distribution scheme using minimum spanning tree (MST) method. The simulation results show that the proposed algorithm has superior performance in comparison with existing algorithms.Keywords: MANETs, IDS, power control, minimum spanning tree
Procedia PDF Downloads 3634008 A Bathtub Curve from Nonparametric Model
Authors: Eduardo C. Guardia, Jose W. M. Lima, Afonso H. M. Santos
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This paper presents a nonparametric method to obtain the hazard rate “Bathtub curve” for power system components. The model is a mixture of the three known phases of a component life, the decreasing failure rate (DFR), the constant failure rate (CFR) and the increasing failure rate (IFR) represented by three parametric Weibull models. The parameters are obtained from a simultaneous fitting process of the model to the Kernel nonparametric hazard rate curve. From the Weibull parameters and failure rate curves the useful lifetime and the characteristic lifetime were defined. To demonstrate the model the historic time-to-failure of distribution transformers were used as an example. The resulted “Bathtub curve” shows the failure rate for the equipment lifetime which can be applied in economic and replacement decision models.Keywords: bathtub curve, failure analysis, lifetime estimation, parameter estimation, Weibull distribution
Procedia PDF Downloads 4374007 Lifetime Assessment for Test Strips of POCT Device through Accelerated Degradation Test
Authors: Jinyoung Choi, Sunmook Lee
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In general, single parameter, i.e. temperature, as an accelerating parameter is used to assess the accelerated stability of Point-of-Care Testing (POCT) diagnostic devices. However, humidity also plays an important role in deteriorating the strip performance since major components of test strips are proteins such as enzymes. 4 different Temp./Humi. Conditions were used to assess the lifetime of strips. Degradation of test strips were studied through the accelerated stability test and the lifetime was assessed using commercial POCT products. The life distribution of strips, which were obtained by monitoring the failure time of test strip under each stress condition, revealed that the weibull distribution was the most proper distribution describing the life distribution of strips used in the present study. Equal shape parameters were calculated to be 0.9395 and 0.9132 for low and high concentrations, respectively. The lifetime prediction was made by adopting Peck Eq. Model for Stress-Life relationship, and the B10 life was calculated to be 70.09 and 46.65 hrs for low and high concentrations, respectively.Keywords: accelerated degradation, diagnostic device, lifetime assessment, POCT
Procedia PDF Downloads 4094006 Recombination Center Levels in Gold and Platinum Doped N-Type Silicon
Authors: Nam Chol Yu, Kyong Il Chu
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Using DLTS measurement techniques, we determined the dominant recombination center levels (defects of both A and B) in gold and platinum doped n-type silicon. Also, the injection and temperature dependence of the Shockley-Read-Hall (SRH) carrier lifetime was studied under low-level injection and high-level injection. Here measurements show that the dominant level under low-level injection located at EC-0.25eV(A) correlated to the Pt+G1 and the dominant level under high-level injection located at EC-0.54eV(B) correlated to the Au+G4. Finally, A and B are the same dominant levels for controlling the lifetime in gold-platinum doped n-silicon.Keywords: recombination center level, lifetime, carrier lifetime control, gold, platinum, silicon
Procedia PDF Downloads 1484005 Recombination Center Levels in Gold and Platinum Doped N-type Silicon for High-Speed Thyristor
Authors: Nam Chol Yu, GyongIl Chu, HoJong Ri
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Using DLTS (Deep-level transient spectroscopy) measurement techniques, we determined the dominant recombination center levels (defects of both A and B) in gold and platinum doped n-type silicon. Also, the injection and temperature dependence of the Shockley-Read-Hall (SRH) carrier lifetime was studied under low-level injection and high-level injection. Here measurements show that the dominant level under low-level injection located at EC-0.25 eV (A) correlated to the Pt+G1 and the dominant level under high-level injection located at EC-0.54 eV (B) correlated to the Au+G4. Finally, A and B are the same dominant levels for controlling the lifetime in gold-platinum doped n-silicon.Keywords: recombination center level, lifetime, carrier lifetime control, Gold, Platinum, Silicon
Procedia PDF Downloads 594004 Ion Thruster Grid Lifetime Assessment Based on Its Structural Failure
Authors: Juan Li, Jiawen Qiu, Yuchuan Chu, Tianping Zhang, Wei Meng, Yanhui Jia, Xiaohui Liu
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This article developed an ion thruster optic system sputter erosion depth numerical 3D model by IFE-PIC (Immersed Finite Element-Particle-in-Cell) and Mont Carlo method, and calculated the downstream surface sputter erosion rate of accelerator grid; Compared with LIPS-200 life test data, the results of the numerical model are in reasonable agreement with the measured data. Finally, we predict the lifetime of the 20cm diameter ion thruster via the erosion data obtained with the model. The ultimate result demonstrates that under normal operating condition, the erosion rate of the grooves wears on the downstream surface of the accelerator grid is 34.6μm⁄1000h, which means the conservative lifetime until structural failure occurring on the accelerator grid is 11500 hours.Keywords: ion thruster, accelerator gird, sputter erosion, lifetime assessment
Procedia PDF Downloads 5544003 Benchmarking Service Quality among Quick-Service Restaurants towards Service Innovations
Authors: Scott Earthy Baldo, Anna Cred Patricia Barroma, Miguel Angelo Eñano, John Ares Hipolito, Orange Sundra Sison, Rixielle Gwendale Tumambing
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Service Innovation is the introduction of several new-fangled ways on how to deliver service to customers with the intention to improve one’s existing service quality and to attract more customers. This research paper aims to identify the various service practices being implemented on the different quick-service restaurants within Morayta Street, Manila, Philippines and compare each establishment to the best within the industry through the process of benchmarking towards service innovations. In order for the gathering of valuable data to be possible, a mixed-method approach was used, wherein qualitative data were taken from the managers of each establishment, indicating the service practices being used, and quantitative data were collected from the customers and employees regarding their perception towards the present service quality of each selected quick-service restaurants, in line with the current service innovations being implemented. This research was conducted in order to discern which service practices are effective in attracting customers and boosting their satisfaction for future references of practitioners who are planning to manage a quick-service restaurant and for students studying in the field of hospitality, specifically on service.Keywords: benchmarking, quick-service restaurants, service innovations, service quality
Procedia PDF Downloads 3644002 Applying Transformative Service Design to Develop Brand Community Service in Women, Children and Infants Retailing
Authors: Shian Wan, Yi-Chang Wang, Yu-Chien Lin
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This research discussed the various theories of service design, the importance of service design methodology, and the development of transformative service design framework. In this study, transformative service design is applied while building a new brand community service for women, children and infants retailing business. The goal is to enhance the brand recognition and customer loyalty, effectively increase the brand community engagement by embedding the brand community in social network and ultimately, strengthen the impact and the value of the company brand.Keywords: service design, transformative service design, brand community, innovation
Procedia PDF Downloads 4914001 CERD: Cost Effective Route Discovery in Mobile Ad Hoc Networks
Authors: Anuradha Banerjee
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A mobile ad hoc network is an infrastructure less network, where nodes are free to move independently in any direction. The nodes have limited battery power; hence, we require energy efficient route discovery technique to enhance their lifetime and network performance. In this paper, we propose an energy-efficient route discovery technique CERD that greatly reduces the number of route requests flooded into the network and also gives priority to the route request packets sent from the routers that has communicated with the destination very recently, in single or multi-hop paths. This does not only enhance the lifetime of nodes but also decreases the delay in tracking the destination.Keywords: ad hoc network, energy efficiency, flooding, node lifetime, route discovery
Procedia PDF Downloads 3374000 Service Delivery Process in the Luxury Hotel Industry in Dubai: A Hoteliers’ Perspective
Authors: Veronique Gregorec, Prakash Vel, Collins A. Brobbey
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Service delivery process in the face of ever changing customer expectations could not have been more important in glamorous Dubai luxury hotel service sector. Based on in-depth discussions with Dubai luxury hotel service pioneers, customer expectations, service processes, customer complaining behavior, and service recovery strategies in the luxury hotel industry are evaluated from the perspectives of service providers. Findings are in agreement with the statement that in the service industry the customer is not always right, and that hotel service providers have acknowledged the need to take extra measures towards individualized and personal service experience delivery. Ultimately, hoteliers set highest standards at all stages of the service delivery process in order to achieve positive and high customer ratings in all customer evaluation areas.Keywords: luxury hotels, Dubai hotels, Dubai hospitality industry, guest service process
Procedia PDF Downloads 4893999 Theoretical Prediction on the Lifetime of Sessile Evaporating Droplet in Blade Cooling
Authors: Yang Shen, Yongpan Cheng, Jinliang Xu
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The effective blade cooling is of great significance for improving the performance of turbine. The mist cooling emerges as the promising way compared with the transitional single-phase cooling. In the mist cooling, the injected droplet will evaporate rapidly, and cool down the blade surface due to the absorbed latent heat, hence the lifetime for evaporating droplet becomes critical for design of cooling passages for the blade. So far there have been extensive studies on the droplet evaporation, but usually the isothermal model is applied for most of the studies. Actually the surface cooling effect can affect the droplet evaporation greatly, it can prolong the droplet evaporation lifetime significantly. In our study, a new theoretical model for sessile droplet evaporation with surface cooling effect is built up in toroidal coordinate. Three evaporation modes are analyzed during the evaporation lifetime, include “Constant Contact Radius”(CCR) mode、“Constant Contact Angle”(CCA) mode and “stick-slip”(SS) mode. The dimensionless number E0 is introduced to indicate the strength of the evaporative cooling, it is defined based on the thermal properties of the liquid and the atmosphere. Our model can predict accurately the lifetime of evaporation by validating with available experimental data. Then the temporal variation of droplet volume, contact angle and contact radius are presented under CCR, CCA and SS mode, the following conclusions are obtained. 1) The larger the dimensionless number E0, the longer the lifetime of three evaporation cases is; 2) The droplet volume over time still follows “2/3 power law” in the CCA mode, as in the isothermal model without the cooling effect; 3) In the “SS” mode, the large transition contact angle can reduce the evaporation time in CCR mode, and increase the time in CCA mode, the overall lifetime will be increased; 4) The correction factor for predicting instantaneous volume of the droplet is derived to predict the droplet life time accurately. These findings may be of great significance to explore the dynamics and heat transfer of sessile droplet evaporation.Keywords: blade cooling, droplet evaporation, lifetime, theoretical analysis
Procedia PDF Downloads 1373998 Consolidating Service Engineering Ontologies Building Service Ontology from SOA Modeling Language (SoaML)
Authors: Purnomo Yustianto, Robin Doss, Suhardi, Novianto Budi Kurniawan
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As a term for characterizing a process of devising a service system, the term ‘service engineering’ is still regarded as an ‘open’ research challenge due to unspecified details and conflicting perspectives. This paper presents consolidated service engineering ontologies in collecting, specifying and defining relationship between components pertinent within the context of service engineering. The ontologies are built by way of literature surveys from the collected conceptual works by collating various concepts into an integrated ontology. Two ontologies are produced: general service ontology and software service ontology. The software-service ontology is drawn from the informatics domain, while the generalized ontology of a service system is built from both a business management and the information system perspective. The produced ontologies are verified by exercising conceptual operationalizations of the ontologies in adopting several service orientation features and service system patterns. The proposed ontologies are demonstrated to be sufficient to serve as a basis for a service engineering framework.Keywords: engineering, ontology, service, SoaML
Procedia PDF Downloads 179